Treatment of Complex Cyanide Compounds for Reuse or …infohouse.p2ric.org/ref/15/14195.pdf · Ferrocyanide can be oxidized to ferricyanide in overflow photo- ... ilembrane Electrolysis

E P A - R 2 - 7 3 - 2 6 9 Juri? 1 9 7 3

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O F F I C E OF RESEARCH AND MONITORING U. S. ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D . C . 20460

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TREATMENT OF COMPLEX CYANIDE

COMPOUNDS FOR R E U S E OR D I S P O S A L

T h o m a s N . H e n d r i c k s o n D r . L o u i s G . D a i g n a u l t

P r o j e c t #12120 ERF

P r o j e c t O f f i c e r

T h o m a s D e v i n e N e w E n g l a n d B a s i n s O f f i c e , E P A

240 H i g h l a n d A v e n u e N e e d h a m H e i g h t s , M a s s a c h u s e t t s 02194

EPA Review Notice

This r e p o r t has been roviowed b y the U.S. Environmcntal Protection Agency, and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the Environmental Protection Agency, nor does mention of trade names or commercial products con- stitute endorsement or recommendation for use.

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Numerous a n a l y t i c a l p r o c e d u r e s . w e r e d e v e l o p e d t o enhance t h e a c c u r a c y o f sample a n a l y s i s o v e r t h e c o n c e n t r a t i o n r a n g e s t u d i e d .

F e r r o c y a n i d e can b e o x i d i z e d t o f e r r i c y a n i d e i n o v e r f l o w pho to - g r a p h i c c o l o r p r o c e s s b l e a c h e s u s i n g e i t h e r e l e c t r o l y s i s o r ozone and t h e w a s t e b l e a c h r e c i r c u l a t e d f o r r e u s e i n t h e p r o c e s s . D i l u t e c o n c e n t r a t i o n s o f f e r r i c y a n i d e c a n b e d e s t r o y e d u s i n g ozone o r c h l o r i n e u n d e r p r o p e r c o n d i t i o n s o f t e m p e r a t u r e , pH,

r I and c a t a l y s t a d d i t i o n .

A c o s t a n a l y s i s i s i n c l u d e d f o r a l l methods t h a t were judged a c c e p t a b l e f o r commercial d e m o n s t r a t i o n . C o s t d a t a f o r .each p r o c e d u r e i s b a s e d upon an " a v e r a g e combined" p h o t o g r a p h i c p r o c e s s o r as d e f i n e d i n t h e r e p o r t .

T h i s r e p o r t was s u b m i t t e d i n f u l f i l l m e n t o f P r o j e c t 12120 E 2 F , unde r t h e p a r t i a l s p o n s o r s h i p o f t h e U . S . Envi ronmen ta l P r o t e c t i o n Agency.

Key Words:

Ozone F e r r i c y a n i d e Complex Cyanides P h o t o f i n i s h i n g Wastes Chemical Recovery Waste R e c y c l e P r e c i p i t a t i o n C h l o r i n a t i o n

iii

Section

I.

11.

111.

I V .

V.

VI.

VII.

VIII.

IX.

X.

XI.

t d I

TABLE OF CONTENTS

Dcs c r i p t ion

C o n c l u s i o n s

Recommendations

Introduction

Materials fr Apparatus

Procedures

Discussion of Results

Full Scale Ozone Bleach Regeneration and Waste Destruction Installation-- Berkey Photo

Acknowledgments

References

Glossary

Appendices

Page

1

3

5

1 7

21

39

101

107

109

115

119

V

FIGURES

Numb e 1’ Description Page 15.

1.

2 .

3 .

4 .

5.

6.

7 .

8.

9 .

10.

11.

12.

13.

14.

Bench Top Non-Membrane Electrolysis Cell

ilembrane Electrolysis Cell

Pilot Plant Non-Membrane Electrolysis Cell

23

25 16.

26 17. 27

29

Pilot Plant Electrolytic Cell

Pilot Plant Ozone Regeneration Cell 15.

Laboratory Ozone Generator and Air Preparation System

Pilot Plant Ozonation or Chlorination Cell

30 19.

20.

3 1 21.

33 Precipitation Studies Stirring System

Continuous Flow Centrifugation System 35

4 3 Absorbance Curve for Prussian Blue

Absorbance--Total Fe(CN)6 Concentration from 0.0 t o 1.0 mg/litar at 700 mp

Absorbance-:Total Fe (CN) Concentration from 0.0 to 25 mg/liter at 700 mp

4 4

4 5

Percent Unconverted Ferrocyanide--Percent The0 r e t i ca 1 C onv e r s i on Non- bleno r ane E 1 ec t r o 1 y s is at Various Current Density Ratios 50

Sffect of Current Density Ratio on Conversion of Ferrocyanide to Ferricyanide in an Electro- lytic Cell 5 1

2 2 .

2 3 .

.24.

25

26

vi

Page

23

25

26

27

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3 0

31

33

3 5

43

4 4

45

50

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x u1:\b c '1'

15. -

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17.

18.

19.

20.

21.

22.

23.

.24.

25

26

Dcscription

E f f c c t of Currcnt Dciisity Ratio on Ferrocyanide Oxidation Rate for Non- Ncmbrane Electrolytic Cell

Comparison of the Actual and Theoretical Conversions of Ferrocyanide t o Ferricyanide in a Membrane Type Electrolytic Cell

Current-Temperature Relationship for a Mem- brane Type Electrolytic Cell

Schematic of an Electrolytic Bleach Regener- ation System

Conversion--Time Curve for Ozone Regeneration

Effect of Solution Flow Rate on Ferrocyanide During Pilot Plant Ozonation Studies

Flow Schematic of A Photographic Bleach Re- generation System Using Ozone

Rate of Degradation of Total Fe(CN)6 During Ozone Oxidation Between 70"-90°C

Effect of Temperature on Fe(CN)6 During Acid Ozone Oxidation

Ozone Destruction of Ferrocyanide: A Flow Schematic

Effect of Rotor Speed on Solution Clarizy for Iron Precipitation of Complex Cyanide Using Various Flocculants

Effect o f Rotor Speed on Solution Clarity for Manganese Precipitation of Complex Cyanide Using Various Flocculants

vii

Page

53

5 4

55

5 9

61

6 7

58

72

7 3

7.;

8 4

Numb e r

27.

-

28.

29.

3 0 .

.a

3 1

32

33

34

35

36

37

3 7A

Description Page. Numb - 5

Effect of Rotor Speed on Solution Clarity for Cadmium Precipitation of Complex Cyanide U s i n g Various Flocculants

-

85

Effect of Rotor Speed on Solution Clarity for Copper Precipitation of Complex Cyanide Using Various Flocculants 86

Lficct 0; Aotor Speed on Solution Clarity for zinc precipitation of Complex Cyanide Using Various Flocculants

Effect of Flow Rate on Solution Clarity for Iron Precipitation of Complex Cyanide Using Various Flocculants

Effect of Flow Rate On Solution Clarity for Manganese Precipitation of Complex Cyanides Using Various Flocculants 89 Effect of Flow Rate on Solution Clarity for Cadmium Precipitation Using Various Flocculants. 90 Effect of Flow Rate on Solution Clarity for Copper Precipitation of Complex Cyanides Using Various F1 occul an ts

Effect of Flow Rate on Solution Clarity for Zinc Precipitation of Complex Cyanides Using Various Flocculants 92

Rate of Loss of Ferricyanide During Ambient

Rate of Loss of Ferricyanide During Elevated

Chlorination System: Flow Schematics

Flow Diagram of Bleach Regeneration System

91

Temperature Chlorine Oxidation 94

Temperature Chlorine Oxidation 35

99

100 and Concentrated Waste Oxidation System

3

4

4

viii

e

r z

or

i n t s .

.ns

Zinc . ous

Numb c 1' D e s c r i p t i o n Page4

5s Ozone G e n e r a t i o n and D i s t r i b u t i o n i Systems I n s t a l l e d a t Berkey F i lm

8s'i P r o c e s s i n g P l a n t , F i t c h b u r g , Mass- t e c h u s e t t s fi

Page

102

39 F e r r i c y a n i d e B leach R e g e n e r a t i o n Tanks I 861

u a t Berkey F i lm P r o c e s s i n g P l a n t F i t c h b u r g , f hias s ac hus e t t s 103

1 40 Waste T r e a t m e n t Tanks a t Berkey F i lm P r o - 8 c e s s i n g , F i t c h b u r g , M a s s a c h u s e t t s 105

4 1 P h o t o g r a p h i c S o l u t i o n T e s t i n g S t a t i o n a t Berkey F i l m P r o c e s s i n g P l a n t F i t c h b u r g ,

8 M a s s a c h u s e t t s 1 0 6

F 8 9;

90

j I

I , ix

TABLES

XI I Numb e r

I

11

Analysis of Ferro-and Ferricyanide With Nitro Prusside as an Interfering Ion

IV

V

VI

VI I

VIIi

IX

X

XI

XI IA

XI IB

Page

XI I

Dcscription

Sodium Ferricyanide [Na3Fe (CN) 61 Concentration as Determlned by Iodometric Titration Methods

Sodium Ferrocyanide [NadFe(CN)6* 10 HzO] Concentration as Determined by Cerimetrlc Titration Method

40

41

4 8

Conversion Efficiency of Pilot Plant Non-Membrane Electrolytic Cell

Comparison of Experimental Results , to Stoichiometric Calculations

Results of Bench Top Ozonation of Used Photographic Bleach

Results of Ozone Destruction of Ferro- cyanide at Ambient Temperature

Effect of Initial pH on Ferrocyanide [Fe (CN)6-4] Concentration

Effect of Initial pH on Heavy Metal Ferrocyanide Precipitation Rate

57

63

6 4

77

77

Effect of Excess Heavy Metal on Ferro- cyanide [Fe (CN) 6-41 Solution Concentration 78

Effect of Temperature zn Heavy Sletal Ferrocyanide [Fe(CN)6- ] Concentration 78

Heavy Metal Precipitation of Complex Cyanides f r m Solutions Containing Both Ferro-and Ferricyanide Salts (mg/l ferrocyanide) 79

Heavy Metal Precipitation of Complex Cyan- ides from Solutions Containing Both Ferro- and Ferricyanide Salts (mg/l ferricyanide) 79

X

XXIXA Page i

i XIIIB

40 t

41

48

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63

6 4

70 j I

Effect of Settling Time 0 0 Fcrrocyanidc Concentration

Effec t o f S e t t l i n g T i m e on Ferricyanide Concontration

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SNOISfl73N03

I N O I . I . 3 ~ 1 S

SECTION I 1

RECOMMENDATIONS

The r e s u l t s o f t h i s p r o j e c t d e m o n s t r a t e s u c c e s s f u l methods f o r e l i m i n a t i n g t o x i c complex c y a n i d e s from p h o t o g r a p h i c w a s t e waters. S i n c e t h i s compound r e p r e s e n t s a h a z a r d i n t h e f o r m o f t o x i c c y a n i d e i o n , and s i n c e i t i s n o t b i o d e g r a d e d i n munic- i p a l s e c o n d a r y t r e a t m e n t p l a n t s , i t must be t r e a t e d a t i t s sou rce .

The r e s u l t s o f t h i s r e p o r t s h o u l d b e made a v a i l a b l e t o :

- r e g u l a t o r y commit tees e s t a b l i s h i n g chemica l l imits f o r s t r e a m s and s e w e r s ,

- m u n i c i p a l r e g u l a t o r y a g e n c i e s t h a t must b e conce rned w i t h t h e d e p o s i t i o n o f t h e compounds i n m u n i c i p a l s e w e r s ,

- m u n i c i p a l t r e a t m e n t p l a n t o p e r a t o r s , and

- p h o t o g r a p h i c p r o c e s s i n g p l a n t s d i s c h a r g i n g t o x i c complex c y a n i d e s .

S i n c e t h e r e a r e obv ious economic a d v a n t a g e s f o r r e d u c i n g t h e d i s c h a r g e of f e r r o c y a n i d e s , no p l a n t s h o u l d b e a l l o w e d t o con- t i n u e t o dump waste w a t e r s c o n t a i n i n g ha rmfu l c o n c e n t r a t i o n s of t h i s compound.

3

I N T R O D U C T I O N

Thc p u r p o s e o f t h i s i n v e s t i g a t i o n was t o e v a l u a t e e l e c t r o l y t i c and ozone o s i d a t i o n t e c h n i q u e s f o r t h e r e g e n e r a t i o n of f e r r o - c y a n i d e i o n f o r reuse and t o e v a l u a t e o z o n a t i o n , p r e c i p i t a t i o n and c h l o r i n a t i o n f o r t h e t r e a t m e n t o f w a s t e s o l u t i o n s c o n t a i n - i n g complex c y a n i d e s from f i l m p r o c e s s i n g w a s t e d i s c h a r g e s . A maximum r e s i d u a l f e r r o c y a n i d e concen t r a t ion of 0 . 4 mg/l was t h e g o a l e s t a b l i s h e d f o r t r e a t e d w a s t e .

5

TOXICITY O F F E R R O - A N D FERRICYANIDE

F e r r o - a n d f c r r i c y a n i d e compounds c a u s e o n l y s l i g h t s k i n i r r i t a - t i o n on d i r e c t c o n t a c t . t o x i c t o humans. o n l y s l i g h t a c u t e o r c h r o n i c s y s t e m i c t o x i c i t y upon i n g e s t i o n . ( l )

Burd ick and L i p s c h u e t z r e p o r t t h a t , " P o t a s s i u m f e r r o c y a n i d e and f e r r i c y a n i d e have n o t b e e n c o n s i d e r e d a s p a r t i c u l a r l y t o x i c ( t o f i s h ) . " ( 2 ) The t o x i c i t y t o f i s h and o t h e r acquatic l i f e i s r e - p o r t e d t o be d i r e c t l y a s s o c i a t e d w i t h s t r o n g u l t r a v i o l e t i r r a - d i a t i o n , a s f rom s u n l i g h t . ( 3 ) (4) (5) ( 6 )

L u r ' e and Panova ( 7 ) h a v e shown t h a t f e r r o c y a n i d e f i r s t o x i d i z e s t o f e r r i c y a n i d e w i t h a i r i n w a t e r and t h e n p h o t o c h e m i c a l l y oxi- d i z e s t o i r o n h y d r o x i d e , h y d r o c y a n i c a c i d and s i m p l e s o l u b l e c y a n i d e s . The p r o p o s e d mechanism i s :

N e i t h c r compound i s Cons ide red t o b e Both compounds have b e e n r e p o r t e d a s c a u s i n g

O v e r a l l R e a c t i o n :

4 Fe(CN)6-4 + O 2 + 1 4 H 2 0 lp 4 Fe(OH)3 + 1 2 HCN + 4 OH' + 1 2 CN-

They r e p o r t t h a t t h e r a t e o f o x i d a t i o n o f f e r r o c y a n i d e i n t h e p r e s e n c e of s u n l i g h t l e a v e s a b o u t 2 5 % o f t h e o r i g i n a l c r n c e n - t r a t i o n i n f i v e days . . . . . t h e f e r r o c y a n i d e d i s a p p e a r i n g c o m p l e t e l y i n 1 0 - 1 2 d a y s .

A r e c e n t government r e p o r t h a s c o n f i r m e d t h e i n c r e a s e d t o x i c i t y o f complex c y a n i d e s f rom p h o t o g r a p h i c w a s t e s i n t h e p r e s e n c e o f s u n l i g h t . v e r s i o n o f complex c y a n i d e t o v o l a t i l e c y a n i d e ( H C X ) i s p r o b a b l y r e v e r s i b l e and p r o d u c t l i m i t e d . The t e s t i n g was c a r r i e d o u t u s i n g an Ektachrome p h o t o g r a p h i c w a s t e s i m i l a r t o a l l commercial f i l m p r o c e s s i n g f e r r i c y a n i d e b l e a c h e s .

The r e s u l t s o f v a r i o u s t e s t s show t h a t t h e C O A -

The r e p o r t s t a t e s :

"The r e s u l t s of t h i s p r e l i m i n a r y e x p e r i - ment i n d i c a t e t h e c o n v e r s i o n of complex c y a n i d e s t o h i g h l y t o x i c H C N o c c u r s r a p - i d l y and i s o f g r e a t t o x i c o l o g i c a l s i g n i - f i g a n c e when d i s p o s i n g of u n t r e a t e d pho to - g r a p h i c w a s t e . An E A - 4 (Ektachrome pho to - g r a p h i c ) s o l u t i o n of 4 m l / l ( a c o n c e n t r a - t i o n which k i l l e d no f i s h i n 9 6 h o u r s w i t h - o u t s u n l i g h t p r e s e n t ) g e n e r a t e d o v e r 2 2 0

6

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tiiiics tlic LC ( 5 0 ) o f frcc c y n n i t l c ( t a k e n €rolii i Jntcr Q u a l i t y C r i t e r i a , blcKcc a n d IL'olf, 1903; C n l i f o r n i a S t a t c N a t c r Q u n l - i t y C o n t r o l E o n r d a s 0 . 0 5 i n g / l ) i n s i x h o u r s ~ I i c n exposed t o s u n l i g h t . l y , t h e c y a n i d e b l e a c h c a n n o t b e d i s c h a r g e d u n t r e a t e d w i t h o u t t h e r i s k of a ma jo r f i s h k i l l . any c i r c u m s t a n c e s i s n o t recommended." ( 8 )

Obvious-

D i s p o s a l o f u n t r e a t e d b l e a c h u n d c r

Eastman Kodak has " V e r i f i e d t h e conversion t o c y a n i d e i n o u r r a t h e r e x t r e m e e x p e r i - ments w i t h f i s h . A 6 , 0 0 0 - W xenon lamp ws used t o s i m u l a t e s u n l i g h t . The i n t e n s i t y a t t h e s u r f a c e o f t h e a q u a r i a was a b o u t 6 , 0 0 0 f o o t c a n d l e s . p r e p a r e d s o t h a t t h e f e r r i G y a n i d e and f e r r o c y a n i d e were o f t h e o r d e r o f a few hundred m i l l i g r a m s p e r l i t e r . F i s h were p l a c e d i n t h e a q u a r i a w i t h t h e f e r r o c y a n i d e and f e r r i c y a n i d e c o n t e n t a t t h a t r e l a t i v e l y h i g h c o n c e n t r a t i o n . I n e x p e r i m e n t s w i t h - o u t t h e xenon lamp, t h e f i s h l i v e d d u r i n g t h e t e s t p e r i o d j u s t a s d i d t h e f i s h i n t h e s t a n d a r d t a p w a t e r . t h e same 9 6 hour t e s t was r e p e a t e d w i t h t h e xenon lamp i l l u m i n a t i n g t h e a q u a r i a con- t i n u o u s l y , t h e f i s h d i e d . " ( 9 )

B leach b a t h s were

However, when

Xew York i s t h e o n l y s t a t e s p e c i f i c a l l y l i m i t i n g t h e d i s c h a r g e o f complex c y a n i d e s i n t o r e c e i v i n g waters . mg/ l Fe (CN)6.

The l i m i t i s 0 . 4

Due t o t h e c o n v e r s i o n o f complex c y a n i d e s i d e s , t h e complex s h o u l d b e c o n v e r t e d t o t h e e q u i v a l e n t amount o f c y a n i d e ( C N ) and compared t o sewer and s t r e a m l i m i t s f o r t h a t l a t t e r compound. The r a n g e o f s ewer c o d e s f o r c y a n i d e i s 0 . 0 t o 1 0 . 0 mg/l ( 1 0 ) w h i l e t h e r a n g e i n s t r e a m s t a n d a r d s i s 0 . 0 t o 1 . 0 mg / l . These v a l u e s depend upon t h e s p e c i f i c c i t y , s t r e a m , p o i n t o f e n t r y , e t c . b u t r e p r e s e n t a r e a s o n a b l e r a n g e o f c o n c e n t r a t i o n s t h a t c y a n i d e t r e a t m e n t equipment s h o u l d be c a p a b l e o f m e e t i n g F e r r o c y a n i d e (Fe ( C N ) - 4 ) i o n c o n c e n t r a t i o n c a n be c o n v e r t e d t o c y a n i d e (CN') by mu t i p l y i n g t h e f e r r o c y a n - i d e c o n c e n t r a t i o n by 0 . 7 .

t o t o x i c s i m p l e cyan-

P S o u r c e s o f F e r r o c y a n i d e and F e r r i c y a n i d e

The f o l l o w i n g i n d u s t r i e s have b e e n l i s t e d i n t h e Condensed C h e n i c a l D i c t i o n a r y , 5 t h E d i t i o n , 1956 a s users of f e r r o c y a n i d e and f e r r i c y a n i d e . (11)

9

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3 . 4. 5 . 6 . 7 . 8 . 9.

1 0 .

1 1 , 12, 13.

7 I .

P h 0 t 0 6 1- 3phy C a l i c o P r i n t i n g Kood Dyeing Tempering S t e e l E t c h i n g L iqu id P r o d u c t i o n o f P igments E 1 e c t r op 1 a t i ng L e a t h e r b l anufac tu r ing Paper blanufac t u r i n g S e n s i t i v e C o a t i n g I n g r e - d i e n t on Blue P r i n t Pape r 1'i ;!lll"llts J J Y C i I I ~ 1'r i l i t i ng

1 ~ I ~ I ~ I ~ O ~ ~ ' ~ A N T 1111

1. Pho tography 2 . B luc Pigments 3 . B l u e p r i n t Paper 4. M c t a l l u r g y 5 . Tanning 6 . Dycs 7 . h led ic ine 8 . R e a g e n t s 9 . Dry C o l o r s

1 0 . Tempering S t e e l 11. E x p l o s i v e s 1 2 , J)roc(::.;s 1 ;3~~ ; rav j ng 13, L i t h o g r a p h y

Iiowcver, s i n c e t h e p r i m e c o n t r a c t o r f o r P r o j e c t 1 2 1 2 0 ERF i s 3 p h o t o g r a p h i c p r o c e s s o r , t h e p r i m a r y o b j e c t i v e was t h e r e d u c - t i o n of complex c y a n i d e s from t h i s s o u r c e o f w a s t e e f f l u e n t . The, r e u s e o f any w a s t e depends upon a number o f p a r a m e t e r s , i n c lu3 i 112 s 3 111 t i 011 p u r i t)', chein i c a l , conc en t r a t i o n , t emper a t u r e , eti. S i n c e t h e i r a r i a b l e s i n t h e methods o f complex c y a n i d e r e u s e s t u d i e d were r e l a t e d s p e c i f i c a l l y t o p h o t o g r a p h i c p r o - c e s s i n g a p p l i c a t i o n s , i t i s n o t a n t i c i p a t e d t h a t t h e s y s t e m s recommended f o r t h i s a p p l i c a t i o n w i l l h a v e d i r e c t a p p l f c a t i o n i n o t h e r i n d u s t r i e s .

The s t u d y o f complex c y a n i d e s f o r t o t a l d e s t r u c t i o n i s more i n d e p e n d e n t o f s p e c i f i c i n d u s t r y a p p l i c a t i o n , s i n c e o n l y t h e c o n c e n t r a t i o n and volume o f s o l u t i o n need b e known t o d e s i g n a p r e l i m i n a r y sys t em u s i n g d a t a i n c l u d e d i n t h i s r e p o r t .

The y e a r l y d i s c h a r g e o f f e r r i c y a n i d e s a l t s f rom p h o t o g r a p h i c s o u r c e s h a s been e s t i m a t e d a t 5 , 0 0 0 , 0 0 0 pounds . (12)

F e r r i c y a n i d e i n P h o t o g r a p h i c P r o c e s s i n g h 'as tes

F e r r i c y a n i d e b l e a c h e s a r e found i n c o l o r p h o t o g r a p h i c p r o c e s s i n g a p p l i c a t i o n s ( s e e Appendix F ) , where i t h a s been u s e d a s a s t a n - d a r d b l e a c h i n g a g e n t f o r y e a r s . The f u n c t i o n o f t h e b l e a c h i n t h e p h o t o g r a p h i c p r o c e s s i s t o o x i d i z e t h e m e t a l l i c s i l v e r i n t h e p h o t o g r a p h i c e m u l s i o n t o a s i l v e r h a l i d e . Dur ing t h a t o s i d a - t i o n , t h e f e r r i c y a n i d e and h a l i d e i o n c o n c e n t r a t i o n s o f t h e b a t h d e c r e a s e , w h i l e t h e f e r r o c y a n i d e c o n c e n t r a t i o n i n c r e a s e s . Bromide i o n i s t h e most common h a l i d e i o n . The r e a c t i o n for p h o t o g r a p h i c b l e a c h i n g i s :

- 4 I

Ago + Fe(CN)6-3 + B r ' + AgBr+ + Fe(CN)6

T O t h e TI. 3 f c 1 f o l for. Ph'

SOC (X2

SOC (Ne

SOC (N2

S O (

soc

SOC

1

LC -

, r e ,

n

i n g an - n

i d a - a t h Dmide 3 h i c

TO a i c ~ i n t a i n t h c prope1- c o n c c n t r a t i o n OF' s o l u t i o n c o n s t i t u e n t s , t h e s o l u t i o 1 1 i s c o n s t a n t l y r c p l c n i s l i c d w i t h f r c s h m a t e r i a l . T h a t d i s t i n g u i s l l c s t h c two pr i inary s o l u t i o n s f o r a l l p r o c e s s ins f o r m u l a t i o n s , t h e r c p l e n i s h c r and working t a n k s o l u t i o n s . Thc f o l l o w i n g i l l u s t r a t i o n shows some t y p i c a l c h e m i c a l concentrations f o r a work ing t a n k and a r e p l e n i s h e r t a n k from t h r e e d i f f e r e n t p h o t o g r a p h i c p r o c e s s e s .

EXAMPLE A

BLEACH BATH COMPOSITION

FROM A TYPICAL COLOR REVERSAL PROCE

Sodium F e r r o c y a n i d e (I\ia4Fe (CN) 6' 1 0 H2O)

Sodium F e r r i c y a n i d e - (Na3Fe (CN) 6 )

Sodium Bromide (NaBr)

s4

W O R K I N G TANK ( g / U

4 5 . 0

1 2 0 . 0

25.0

EXANPLE B

BLEACH BATH COMPOSITION

FROM A TYPICAL COLOR NEGATIVE FILM PROCESSOR

WORKING TANK Cg/U

Sodium F e r r o c y a n i d e D e c a h y d r a t e 6 . 0

Sodium F e r r i c y a n i d e 2 3 . 0

Sodium 3 r o n i d e 1 5 . 0

9

REPLENISHER ( g / U

5 . 0

140.0

r s . 0

2.0

26.0

17.0

EXAMPLE c BLEACH BATH COMPOSITION

FROM A T Y P I C A L COLOR POSITIVE PAPER PROCESSOR

WORKING TANK KEPLENI SHER (s/1) ( E / 1)

Sodium F e r r o c y a n i d e D e c a h y d r a t e 1 3 . 0 4 2 . 0

Sodium F e r r i c y a n i d e 1 7 . 0 2 5 . 0

Sodium Bromide 7 .0 8 . 0

The o v e r f l o w b l e a c h f rom t h e work ing t ank i s one s o u r c e o f f e r r o - c y a n i d e w a s t a g e from t h e p h o t o g r a p h i c p r o c e s s . I n a d d i t i o n , as f i l m p a s s e s t h r o u g h t h e p r o c e s s i n g s o l u t i o n s , i t c a r r i e s a ce r - t a i n volume o f t a n k s o l u t i o n t o t h e n e x t t a n k , T h a t c a r r y o v e r i s t h e t o t a l o f t h e s u r f a c e l i q u i d and t h e s o l u t i o n a b s o r b e d i n t o .the f i l m e m u l s i o n . The c a r r y o v e r r a t e depends upon many f a c t o r s , i n c l u d i n g t h e s p e e d of t h e p r o c e s s and t h e p h o t o p r o - d u c t s b e i n g p r o c e s s e d . The c a r r y o v e r l o s s o f s o l u t i o n b l e a c h i n t o t h e n e x t b a t h i n t h e p r o c e s s i s a s e c o n d s o u r c e o f b l e a c h l o s s . The b a t h f o l l o w i n g t h e b l e a c h i s e i t h e r a p h o t o g r a p h i c f i x i n g b a t h o r a wash wa te r .

X l i p r o c e s s i n g l a b o r a t o r i e s a r e i n a p o s i t i o n t o e s t i m a t e t h e ave rage c o n c e n t r a t i o n o f f e r r i c y a n i d e d i s c h a r g e d f rom t h e p h o t o - g r a p h i c l a b o r a t o r y o v e r a s p e c i f i e d p e r i o d o f t ime. T h a t c a n be done by c a l c u l a t i n g t h e pounds o f f e r r o - o r f e r r i c y a n i d e pu rchased and d i v i d i n g by t h e t o t a l volume o f w a t e r u s e d by t h e l a b o r a t o r y d u r i n g t h e same p e r i o d . e v e r y pound o f f e r r i c y a n i d e p u r c h a s e d i.s a t some t i m e l o s t t o t h e sewer. . I f t h e a v e r a g e c o n c e n t r a t i o n i s above s t r e a m o r m u n i c i p a l s ewer r e g u l a t i o n s ( f o r e i t h e r complex o r s i m p l e cyan- i d e s ) , methods o u t l i n e d i n t h i s r e p o r t c a n b e u s e d t o r e d u c e t h e c o n c e n t r a t i o n t o a c c e p t a b l e l e v e l s .

I n t h e p h o t o g r a p h i c l a b ,

S i n c e a l l c o l o r p h o t o g r a p h i c b l e a c h e s c o n t a i n i n g c y a n i d e a r e d i f f e r e n t o n l y i n c o n c e n t r a t i o n by f a c t o r s o f 3 - 5 , t h e s t a t e - ment t h a t Ektachrome b l e a c h e s , " canno t be d i s p o s e d o f w i t h o u t d e g r a d a t i v e t r e a t m e n t . . . . . . . " ( 8 ) would a p p l y t o a l l b l e a c h e s A f u r t h e r s t a t e m e n t f rom t h e same r e p o r t t h a t , "Under no c i r - cumstances may u n t r e a t e d E A - 4 (Ektachrome) b l e a c h b e s a f e l y r e l e a s e d i n t o any s t ream." ( 8 ) would Thus b e a p p l i c a b l e t o t h e f u l l r a n g e o f p h o t o g r a p h i c b l e a c h e s c o n t a i n i n g complex c y a n i d e s .

A d d i x i o n a l i n f o r m a t i o n on t h e p o l l u t i o n p rob lems i n t h e p h o t o - g r a p h i c i n d u s t r y c a n b e found i n t h e Appendices o f t h i s r e p o r t .

The E f e r r : y s i s

Elec' - In t l t h e 1

Anodl

Fe (C;

Cath,

*ZO Fe (C

The t o f t i o n s t u d t h e by a

I n c r c u r r l a t i (C. 0

w =

An i r e a c r e a c a t e pos s w e I t o f o f s t h i s

Wher cyar W i t i c a n

10

R -

I r r o - as r- r

h

t o -

ie

A-

i

THEORETICAL APPROACH

Tlie me thoJs used i n this s t u d y f o r t h e c o n v c r s i o n o f f e r r o t o f e r r i c y a n i d e , o r t l ie d e s t r u c t i o n o f f e r r o c y a n i d e were : e l e c t r o l - y s i s , o z o n a t i o n , c h l o r i n a t i o n , and c h e m i c a l p r e c i p i t a t i o n .

E l e c t r o l y s i s o f F e r r o c y a n i d e

I n t h e e l e c t r o l y t i c o x i d a t i o n o f f e r r o c y a n i d e t o f e r r i c y a n i d e , t h e most p r o b a b l e anode and c a t h o d e r e a c t i o n s a r e as follows:

Anode R e a c t i o n s :

F ~ ( c N ) ~ - ~ -+ Fe(CN)6

&,OH' -+ 1 / 2 02 + H20 + e' ( s e c o n d a r y r e a c t i o n ) E O = - 0 . 4 0 V o l t s (3)

Cathode R e a c t i o n s :

- 3 + e- ( p r i m a r y r e a c t i o n ) E O = - 0 . 4 9 V o l t s ( 2 )

H20 + e- + 1 / 2 H 2 + OH-

Fe(CN)6-3 + e' + Fe(CN)6'4 ( s e c o n d a r y r e a c t i o n ) &' = 0 . 4 9 V o l t s ( 5 )

The o b j e c t i v e of t h i s s t u d y was t h e c o n v e r s i o n of f e r r o c y a n i d e t o f e r r i c y a n i d e . Thus , m i n i m i z i n g t h e s e c o n d a r y c a t h o d e r e a c - t i o n i s mandatory . Two methods o f o b t a i n i n g t h i s r e s u l t were s t u d i e d : i n c r e a s i n g t h e c a t h o d e c u r r e n t d e n s i t y r e l a t i v e t o t h e anode c u r r e n t d e n s i t y , and s e p a r a t i n g t h e e l e c t r o d e s o l u t i o n by a n i o n pe rmeab le membrane.

I n c r e a s i n g t h e c a t h o d e c u r r e n t d e n s i t y ( r e l a t i v e t o t h e anode c u r r e n t d e n s i t y ) i n c r e a s e s t h e hydrogen o v e r v o l t a g e . The re- l a t i o n s h i p f o r i n c r e a s e d o v e r v o l t a g e (w) w i t h c u r r e n t d e n s i t y (C.D.) i s as f o l l o w s :

(p r imary r e a c t i o n ) € 0 = - 0 . 8 2 8 V o l t s ( 4 )

w = a + B l o g (C.D.)

An i n c r e a s e i n hydrogen o v e r v o l t a g e a t t h e c a t h o d e f o r t h i s r e a c t i o n r e s u l t s i n a b u i l d u p o f hydrogen g a s b u b b l e s (p r imary r e a c t i o n ) a t t h e c a t h o d e s u r f a c e , (13) The gas b u b b l e s i n s u i - a t e t l ie c a t h o d e from t h e f e r r i c y a n i d e s o l u t i o n , r e d u c i n g t h e p o s s i b i l i t y o f t h e s e c o n d a r y c a t h o d e r e a c t i o n . Thus , hydrogen O v e r v o l t a g e would r e s u l t i n a n i n c r e a s e i n t h e o v e r a l l f e r r o - t o f e r r i c y a n i d e c o n v e r s i o n . E x p e r i m e n t a l l y , v a r y i n g t h e r a t i o of anode c u r r e n t d e n s i t y t o c a t h o d e c u r r e n t d e n s i t y would show t h i s e f f e c t .

When a c a t i o n permeable membrane i s u s e d t o s e p a r a t e t h e ferro- c y a n i d e from t h e c a t h o d e , t h e c o n v e r s i o n c a n b e i n c r e a s e d . With membranes o f t h i s t y p e , o n l y t h e p o s i t i v e l y c h a r g e d c a t i o n s c a n p r o d u c e a c u r r e n t t h r o u g h t h e membrane. The sodium o r

11

p o t n s ~ i u i i i i o n s i n t h e anoclc chamber p a s s t h r o u g h t h e mcmbranc a n d arc rccluccd a t t h e cathoclc . Uuc t o i t s n c g a t i v e c h a r g e I c r r i i > * n n i d c c a n n o t p a s s t h r o u g h t h e mcmbrane and b e rcduccd t o ferrocyanide. The c l i n i i n a t i o n 01 t h i s r e d u c t i o n p r o c c s s r e s u l t s i n a h i g h e r o v e r a l l c o n v e r s i o n o f f e r r o - t o f e r r i c y a n i d e ,

T h e o n l y r e q u i r e m e n t s of t h e c a t h o d e s o l u t i o n a r e : t h a t i t b e c o n d u c t i v e , and t h a t i t n o t c o n t r i b u t e o t h e r r e a c t i o n s a t t h e c a t h o d e t h a t would d e c r e a s e t h e c e l l e f f i c i e n c y .

Ozone Conver s ion o f F e r r o - t o F e r r i c y a n i d e

The s t o i c h i o m e t r i c r e l a t i o n s h i p f o r t h e o x i d a t i o n o f f e r r o - c y a n i d e t o f e r r i c y a n i d e w i t h ozone i s a s f o l l o w s :

2 Na4 Fe(CN)6 1 0 H 2 0 + 0 3 + H 2 0 -+ 2 Nag Fe(CN)6 + 02 + 2 NaOH +

20 H 2 0 (7 )

T h i s r e a c t i o n shows t h a t 2 0 . 2 gm o f sodium f e r r o c y a n i d e c a n b e c o n v e r t e d t o 1 1 . 7 gm of sodium f e r r i c y a n i d e by one gram o f ozone . ('14)

With an o x i d a n t a s r e a c t i v e as ozone , t h e r a t e d e t e r m i n i n g s t e p i n t h e above r e a c t i o n s h o u l d b e t h e mass t r a n s f e r o f ozone from t h e gaseous t o t h e s o l u t i o n p h a s e .

I f t h e r a t e o f r e a c t i o n be tween ozone and f e r r o c y a n i d e i s v e r y r a p i d , t h e s o l u t i o n c o n c e n t r a t i o n o f ozone w i l l be n e a r z e r o . Thus , :ne r a t e of a b s o r p t i o n i s p r o p o r t i o n a l t o t h e p a r t i a l p r e s s u r e o f ozone . ( 1 5 )

Ozone Decomposi t ion o f F e r r o c y a n i d e

The d e c o m p o s i t i o n o f t h e f e r r o c y a n i d e i o n h a s b e e n found t o b e a v e r y complex mechanism, i n v o l v i n g a number of compet ing r e a c t i o n s . j l 6 )

(1 p w

- 3 + 2 OH- + 0 2 (8) 2 Fe(CN)6 - 4 + O 3 + H 2 0 + 2 Fe(CNj6

Fe(C,U)be3 Z Fe+3 + 6 CN-

D e s t r u c t i o n o f f r e e c y a n i d e i o n

( 9 )

C N - + O j + OCN- + 02 ( 1 0 )

D e s t r u c t i o n o f c y a n a t e i o n

OCN- + 2H+ + H 2 0 + C02 + NHq'

O C N - + NH4+ + * NH2 CONH2

2 OCN- + H 2 0 + 303 -+ 2 H C O - 3 + N 2 + 3 02

(11)

( 1 2 )

( 1 3 )

12

Fe 1

Fe I

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C O I

0x8

R e i - H e s o me

MX

M+-"

In

S t d i t i

F e r r o c y a n i d e h y d r o l y s i s

Free c y a n i d e b r e a k s down r e a d i l y i n t h e p r e s e n s e o f ozone t o t h e c y a n a t e i o n , which i s g e n e r a l l y c o n s i d e r e d t o be o n l y one o n e - t h o u s a n d t h ( 1 / 1 , 0 0 0 ) a s t o x i c a s c y a n i d e . The c y a n a t e i o n is n o t s t a b l e unde r o x i d a t i o n c o n d i t i o n s , b u t i t s o x i d a t i o n r e a c t i o n i s n o t w e l l u n d e r s t o o d . A p p a r e n t l y , t h e breakdown con- s i s t s o f a combina t ion of r e a c t i o n s , i n c l u d i n g b o t h h y d r o l y s i s and o x i d a t i o n .

The r e a c t i o n o f f e r r i c y a n i d e and ozone a p p a r e n t l y i n v o l v e s t h e removal o f a cyano g roup from t h e f e r r i c y a n i d e complex. Th i s complex t h e n f u r t h e r decomposes t o c y a n a t e and f e r r i c i o n s .

I n t h e p r e s e n c e o f m i n e r a l a c i d s , i r o n c y a n i d e complex i o n s de - compose v i a t h e f o l l o w i n g r e a c t i o n :

3 Hq Fe(CN)6 * 1 2 H C N + F e 2 Fe(CN)6 (1 5)

The f e r r o u s f e r r o c y a n i d e c a n , i n t u r n , be o x i d i z e d t o P r u s s i a n Blue F e 4 [Fe(CN)6] . The e x t e n t o f t h i s d e c o m p o s i t i o n depends upon t h e a c i d i t y 02 t h e s o l u t i o n ; i n c r e a s i n g as t h e pH d e c r e a s e s .

F e r r o c y a n i d e r e a c t s d i f f e r e n t l y i n t h e p r e s e n c e o f o x i d i z i n g a g d s . A t t e m p e r a t u r e s be tween 7 0 " and 80°C, h y p o c h l o r o u s a c i d c o n v e r t s f e r r o c y a n i d e t o f e r r i c y a n i d e , n i t r o p r u s s i d e and f r e e f e r r i c i o n s . When n i t r i c a c i d i s added t o an aqueous f e r r o - c y a n i d e , t h e r e a c t i o n p r o d u c t s a r e r e p o r t e d as f e r r i c y a n i d e , n i t r o p r u s s i d e , hydrogen c y a n i d e , cyanogen , c a r b o n d i o x i d e , oxamide and n i t r o u s a c i d . (16)

Removal o f Heavy Meta l Complex Cyan ides

Heavy m e t a l f e r r o c y a n i d e s a r e o n l y s l i g h t l y s o l u b l e i n water . S o l u b l e s a l t s of t h e heavy m e t a l i o n s a r e u s e d t o form heavy metal f e r r o c y a n i d e s i n t h e f o l l o w i n g manner:

MX + H 2 0 + M -

(16) ++ + X- + H20 (Meta l I o n i z a t i o n )

-+ M2 Fe(CN)6+ (Heavy Metal P r e c i p i t a t i o n ) ( 1 7 ) M++ + Fe(CN)6 -4

I n t h e p r e s e n c e o f an e x t e r n a l f i e l d , t h r e e f o r c e s a c t on a p a r t i c l e which i s moving th rough a l i q u i d . These f o r c e s a r e : . (1) t h e e x t e r n a l f o r c e ( g r a v i t a t i o n a l o r c e n t r i f u g a l ) ; ( 2 ) t h e bouyan t f o r c e ; and (3) t h e d r a g f o r c e . By t h e a p p l i c a t i o n o f S t o k e s law f o r s p h e r i c a l p a r t i c l e s , t.he r a t e o f s e t t l i n g i s d i r e c t l y p r o p o r t i o n a l t o t h e s q u a r e o f t h e r a d i u s o f t h e p a r - t i c l e and t h e d e n s i t y o f t h e p a r t i c l e , and i n v e r s e l y p r o p o r -

t i o i i n l t o t h e v i s c o s i t y of t h c f l u i d . T h e r c f o r e , t h e a d d i t i o n o f a c o a g u l a t i o n a g e n t w i l l i n c r e a s e t h e r a t e of s c t t l i n g o f - t h e p r e c i p i t a t e s due . t o an i n c r e a s e i n p a r t i c l e s i z e ,

C h l o r i n e D e s t r u c t i o n o f Complcx Cyan ides - Var ious r e a c t i o n s have b e e n s u g g e s t e d o r obse rved f o r c h l o r i n e o x i d a t i o n of complex c y a n i d e s . p u r e g a s , a s a s o l u t i o n , o r i n s o l i d form.

h y p d c h l o r i t e i o n as f o l l o w s : ( i 8 j

C h l o r i n e may be added a s a

Gaseous c h ~ o r h n o reacts in &A alkaline solut ion t o form the

C12 + OH- + OC1- + C1- + H+

Fe(CN)6-4 Fe++ + 6 CN- (19)

( 1 8 )

S e v e r a l p o s s i b l e compet ing r e a c t i o n s f o r t h e d e s t r u c t i o n o f f e r r o c y a n i d e by c h l o r i n e a r e c i t e d i n t h e l i t e r a t u r e ; t h e y a r e a s f o l l o w s :

CN-' + OC1- * OCN- + C1- (20) - 2 OCN + 3 OC1- + H20 -+ 2 C02 + N 2 + 2 C1- + OH- (21).

OCN- + 2H+ + H20 + C 0 2 + NH4 +

OCN- + NH4 + N H ? I CONH, .d (23)

OCN- + OH- + 11-9 .- -+ c3- s + NH3 (24)

(22) +

- -

As i n a ~ o i ; ~ : ~ a i i , :.'.c ~ : s t r a c t i o n o f t h e f r c e c y a n i d e i o n i s a r a p i d and w e i l known 2 r o c e s s , w h i l e t h e d e s t r u c t i o n o f t h e cyan- a t e i s s l o w e r and more complex.

The p redominan t s p e c i e s i n s o l u t i o n , w h e n c h l o r i n e i s b u b b l e d i n t o w a t e r o v e r t h e pH r a n g e o f 2 - 6 , i s hypoch lo rous a c i d (HOC1). As ment ioned p r e v i o u s l y , h y p a c h l o r o u s a c i d c o n v e r t s f e r r o c y a n i d e t o f e r r i c y a n i d e , n i t r o p r u s s i d e and f r e e f e r r i c i o n s .

Rate dependence on c a t a l y s t c o n c e n t r a t i o n i s c h a r a c t e r i s t i c o f homogeneous c a t a l y s i s . The c a t a l y s t u s u a l l y a c t s by p r o v i d i n g a mechanism f o r t h e d e c o m p o s i t i o n t h a t h a s c o n s i d e r a b l y ' l o w e r a c t i v a t i o n e n e r g y t h a n t h e u n c a t a l y z e d r e a c t i o n .

Lancy r e p o r t e d t h a t m e r c u r i c s a l t s s p l i t t h e i r o n c y a n i d e s i n a c a t a l y t i c p r o c e s s a l k a l i n e c h l o r i n a t i o n , The p r o p o s e d d e c o m p o s i t i o n i s as f o l l o w s :

(19)

i f t h e d e c o m p o s i t i o n i s coup led w i t h a n

.

14

Hg

2 N

In f c 1' t h e cy a cl; 1 f e r hy:. on 2 o r

DUE s t L P =c

i t i o n o f

I r i n e 1

f

:d

inide roc1)-.

: o f l i ng f e r '

i n .n

1x1 t h i s w o r k , oll ly one mole o f c y a n i d e i s c h l o r i n a t e d f r o m t h e f e r r i c y a n i d e coniples. t h e s e c o n d a r y breakdown o f t h e c y a n i d e compounds w i l l b e t o c y a n a t e s a l t s . The p r o c e d u r e u s e d by Lancy was t o f i r s t hypo- c h l o r i n a t e t h e w a s t e t o c o n v e r t t h e simple c y a n i d e s and o x i d i z e f e r r o - t o f e r r i c y a n i d e . h y p o c h l o r i n a t i o n c o n t i n u e d . one gram p e r l i t e r o f f e r r i c y a n i d e i n t w e n t y - f o u r h o u r s a t 70°F o r i n two h o u r s a t 1 8 0 ' F . ( 2 0 ) ( 2 1 )

The pII must b e a l k a l i n e t o i n s u r e t h a t

The HgC12 c a t a l y s t i s t h e n added and T h i s method was found t o d e s t r o y

Due t o t h e p o l l u t i o n h a z a r d s i n t h e u s e o f m e r c u r y , i t was n o t s t u d i e d i n t h i s r e p o r t . R a t h e r , o t h e r c a t a l y s t s t h a t migh t produce a s imi la r o x i d a t i o n were i n v e s t i g a t e d .

MATE 1: I A L S

NATE li I A L S

Chemical

P o t a s s i u m F e r r o c y a n i d e

P o t a s s i u m F e r r i c y a n i d e

H y d r o c h l o r i c Acid

Sodium Hydroxide

F e r r o u s S u l f a t e

lcanganous S u l f a t e

C u p r i c S u l f a t e

Cadmium S u l f a t e

Z inc C h l o r i d e

N a l c o l y t e , 6 7 0

P u r i f l o c A - 2 3

S t e e l Wool

AND APPAIUTUS

Grade

c r y s t a l

c r y s t a l

3 7 . 8 %

p e l l e t s

g r a n u l a r

p u r i f i e d

t e c h n i c a l

c r y s t a l

t e c h n i c a l

n o n i o n i c f l o c c u l a n t

a n i o n i c f l o c c u l a n t

Grade 3

3ource

J . T . Baker

J . T . Baker

J. T. Baker

J . T . Baker

J . T . Baker

J . T . Baker

W i l l S c i e n t i f i c

J . T . Baker

J . T . Baker

Nalco Chemical Co.

Alken Murray Corp.

Unknown

1 7

. . . . . . . . . , . . . . . . . . . . . . . . . . . .

S p e c t r o p h o t o m e t e r : P e r k i n - E l m e r . Model 139

pH N e t e r : C o r n i n g Model 1 2 R e s e a r c h

B a l a n c e : N e t t l e r H - 1 0 M a c r o a n a l y t i c a l Balance ; c a p a c i t y : 1 6 0 ~ 0 . 0 0 0 0 5 gms

B u r e t t e s : 5 0 . 0 ml

P i p e t s : 1 m l , 5 m l , 1 0 m l , 2 0 ml.

E l e c t r o lys i s o f F e r r o c y a n i d e s

V a r i a c : P o w e r s t a t V a r i a b l e A u t o t r a n s f o r m e r t y p e 1 1 6 B , t h e S u p e r i o r E l e c t r i c Co. , 0 - 1 4 0 VAC

R e c e i f i e r : Varo , t y p e 1 N 4437

Ammeter: Wes te rn Model 8 0 A n a l y z e r , 0.100 amperes

V o l t m e t e r : T r i p l e t t , Model 310 M i n i a t u r e VOM

S t i r r e r : L a b - S t i r , h o l l o w s p i n d l e , Ebe rbach Corp .

Non -Nemb r a n e C e l l

Anodes: S t a i n l e s s S t e e l S c r e e n C y l i n d e r s , Anrod S c r e e n C y l i n d e r C o . , Cass C i t y , M i c h i g a n ; l", 1 . 5 " , 2 . 2 5 " , 3,.25" d i a m e t e r

Ca thodes : S t a i n l e s s S t e e l Rods, U.S.S., 1 / 8 , 1 / 4 , 1 / 2 i n c h d i a m e t e r

Membrane C e l l

R e a c t o r : (See F i g u r e 1, Page 2 2 ) c o n s i s t s o f two p l e x i g l a s s compar tmen t s e a c h 2"W x 3 1 / 2 "L x 4 1 / 2 " H

E l e c t r o d e s : Carbon p l a t e s 3" H x 3" L x 1/4"W ( E l e c t r o Carb EC-4)

S e a l a n t : Dow C o r n i n g , RTV Cement

Membranes: I o n i c s I n c . , C a t i o n No. G1-AZL-066, Watertown M a s s a c h u s e t t s

P i l o t P 1 a n t C e l l

R e a c t o r : (See F i g u r e 3 page 2 6 ) C o n s i s t s o f t h r e e c y l i n d r i c a l p l e x i g l a s s columns w i t h anodes on i n s i d e w a l l s and c a t h - o d e s on c e n t r a l a x e s 36"H x 3"I .D. x 1/ .4"Wall T h i c k n e s s

18

AnoJie

catho

Power

Pump :

F 1 OW

Ozone

A l l S

A i r P

-

Ozone

Bench

React

-

P i l o t

React

Pump :

F l o w

- Bend

Hot I:

Reacl

Spar$

I

AnoJes : Stainless S t c c l P c r i ' o r a t c d C y l i n d c r s , 36" x 3 " O . D.

Cathodes: S t a i n l e s s S t c c l R o d l / S l ' d i a m e t c r , U . S . S .

power S u p p l y : iiollaJ:d Rcctificr, J . H o l l a n d and S o n s , 0-iOV U . C . , 2 5 amperes .

pump:

Flow F ie t e r : F . i d . Dwyer M f g . Co. t y p e VFA-34-BV r a n g e ; 2 0 - 2 0 0

Narch b l a n u f a c t u r i n g C o . , Model L C - 2 A , 115V A . C . , 6 0 c y c l e . Glenview, I l l i n o i s .

ml/min, Michigan C i t y , I n d i a n a ,

Ozone R e g e n e r a t i o n and D e s t r u c t i o n of Complex Cyan ides

. A l l s t u d i e s u s e d t h e f o l l o w i n g equ ipmen t :

A i r P r e p a r a t i o n Sys tem: P u r i f i c a t i o n S c i e n c e s I n c o r p o r a t e d , Geneva, New York, Model AP-1; De\ ipoin t : -40°C; C a p a c i t y : 1 . 8 SCFM a t 8 0 ?SIG.

Ozone G e n e r a t o r : P u r i f i c a t i o n S c i e n c e s I n c o r p o r a t e d , Geneva, New York, Model LOA-2; Flow: 0 - 2 0 SCFH; O u t p u t : 0 - 3 grams p e r hour w i t h p u r e oxygen f e e d .

Bench Top R e g e n e r a t i o n

R e a c t o r : Hydrometer Column; 1 8 1/.2"H x 2 1 / 2 " O . D . x 1 / 8 " i i a l l T h i c k n e s s .

Labpor Gas D i s p e r s i o n Tubes ; B e l - A r t P r o d u c t s , P e q u a n n o c k , N e w J e r s e y ; p o l y e t h y l e n e c a n d l e s , medium p o r o s i t y .

S p a r g e r :

P i l o t P l a n t R e g e n e r a t i o n - (See F i g u r e 4, p a g e 2 7 )

R e a c t o r : C l e a r P l e x i g l a s s Column; 52"H x 3 1 / 2 " I , D . x 1/4" Wall T h i c k n e s s

Pump: March M a n u f a c t u r i n g Co. ; Model L C - 2 A , 1 1 5 v o l t s , 60 c y c l e .

Flow Meter: F.W. Dwyer M a n u f a c t u r i n g Co. ; t y p e VFA-34-BV, r a n g e 20-200 ml/min.

Bench Top D e s t r u c t i o n

Hot P l a t e : Dy la the rm, Model 25202, 5 0 0 w a t t s

R e a c t o r : Kimax B e a k e r , 1 0 0 0 m l .

S p a r g e r : Labpor Gas D i s p e r s i o n Tube; B e l - A r t P r o d u c t s , Pequannock, New J e r s e y ; P o l y e t h y l e n e c a n d l e s , medium p o r o s i t y .

19

Prccipitation

Agitator: Phipps and Bird Six Bladc Multiple Stirrer, O - t l O O rpiii, 1 1 5 v , GO cycle, with florescent 1 amp base i 1 1 uin i n a t o r

Puiiip:

Heater: Sethco Immersion Heater

Eberbach Circulating Pump, Model AA2G108

Centrifugation (See Figure 9, page 3 5 )

Flowmeter: F. W. Dwyer Mfg. Co., Model VFA-34-bv, range 20-200 ml/min

Centrifuge: Sorvall Superspeed Centrifuge with Szent-Gyorgi Blum Continuous Flow Apparatus; Model SS-1, Ivan Sorva\ll Corp., Norwalk, Conn.

. Chlorine Destruction of Complex Cyanides

Chlorine: Bottled, Jones Chemical Co., Caledonia, New York

A s e i me as t The r titri

The 2

were

In ac of SI ultrz test detez

Hypochlorite Solution: Clorox Bleach, Std. 5% hypochlorite The s concentration Apper

Gas Dispersion Tubes: Labpor Polyethylene Candles, Bel-Art Products, Pequannock, New Jersey, medil porosity

Will Gyrathern Stirrer-Hot Plate, Magnetic 60-80 rpm, 0-700°F, Model IIa

Heater:

2 0

~p base

ange

t -Gyorg i S - 1 , Ivan

ew York

h l o r i t e

P R O C E D U R E S

A n a l y t i c a l (Subprogram A)

A sca rc1~ o f the literature yiolded a numbcr o f methods f o r n ~ e a s u ~ i n g t h e c o n c e n t r a t i o n s o f f e r r o c y a n i d e and f e r r i c y a n i d e , The methods i n c l u d e d : c e r i m e t r i c , i o d o m e t r i c and p o t e n t i o m e t r i c t i t r a t i o n s and one c o l o r m e t r i c measurement ,

The above methods were t e s t e d i n t h e l a b and v a r i o u s m o d i f i c a t i were made t o improve t h e a c c u r a c y o f t h e measu remen t s .

I n a d d i t i o n t o t h e methods found i n t h e l i t e r a t u r e , a number of s p e c t r o p h o t o m e t r i c p r o c e d u r e s were d e v e l o p e d u s i n g b o r h t h e u l t r a - v i o l e t and v i s i b l e l i g h t r e g i o n s . The s p e c t r o p h o t o m e t r i c t e s t p r o c e d u r e s were compared w i t h t h e t i t r a t i o n p r o c e d u r e s t o d e t e r m i n e which gave t h e b e s t a c c u r a c y i n t h e s h o r t e s t t i m e ,

The s e l e c t e d p r o c e d u r e s u s e d i n t h i s p r o j e c t c a n b e found i n Appendix D n Page 123,

21

O A S

f

i

I i

E l c c t r o l y s i s o f F c r r o c y a n i d c s (Subprogram U)

sa11 - ;\lCllIb r n l l c c c 11

Thc p o t a s s i u m f e r r o c y a n i d e , IidFe(CN) 6 . 3H20 s o l u t i o n s wcrc p r c - pa red by f i r s t d i s s o l v i n g 10.00+.01 grams o f t h c c r y s t a l i n d i s t i l l e d w a t e r and t l i cn b r i n g i n g t h e t o t a l volume t o one l i t e r , T h i s p roduced a 5 . 0 3 g r a m / l i t e r s o l u t i o n o f i r o n complex c y a n i d e a s Fe(CN)6. F i v e hundred m i l l i l i t e r s o f t h i s s o l u t i o n were added t o a one l i t e r b e a k e r i n which t h e e l e c t r o d e s were immerse( t h u s fo rming t h e c e l l . The power s u p p l y was c o n n e c t e d and t h e v o l t a g e a d j u s t e d t o 3 .5 v o l t s D . C . The r a t i o of c u r r e n k d e n s i t y on t h e c a t h o d e t o c u r r e n t d e n s i t y on t h e anode v a r i e d be tween 0 . 1 and 2 0 . 3 by u s i n g d i f f e r e n t s i z e anodes and c a t h o d e s . Sam- p l e s were c o l l e c t e d v i a a p i p e t f o r a n a l y s i s a t v a r i o u s t i n e s f o r e a c h c u r r e n t d e n s i t y r a t i o .

Tempera tu re s t u d i e s were conduc ted m e a s u r i n g t h e i n c r e a s e i n c u r r e n t ove r a s p e c i f i c t e m p e r a t u r e r a n g e on a number o f c e l l s w i t h c u r r e n t d e n s i t y r a t i o s between 1 and 1 6 . The c e l l s were p l a c e d on a h o t p l a t e and a l l o w e d t o come t o e q u i l b r i u m a t t h e t e m p e r a t u r e u n d e r c o n s i d e r a t i o n and t h e c u r r e n t was t h e n measur - e d . E l e c t r o d e d e p t h , a p p l i e d v o l t a g e , and c o n c e n t r a t i o n were h e l d c o n s t a n t f o r e a c h c e l l . Tempera tu res were v a r i e d f rom 25OC t o 6OoC i n f i v e d e g r e e i n t e r v a l s .

Rec t Bri

Jlembrane Cell

A c a t i o n i c membrane s e p a r a t e s two i n d i v i d u a l c e l l compar tments i n t h e membrane e l e c t r o l y s i s c e l l : t h e anode (+) and t h e c a t h - ode ( - ) . O x i d a t i o n r e a c t i o n s o c c u r a t t h e anode , t h e s o l u t i o n b e i n g r e f e r r e d t o as t h e a n o l y t e . The c a t h o l y t e s o l u t i o n con- t a c t s t h e c a t h o d e .

For t e s t s a t ambien t t e m p e r a t u r e , t h e a n o l y t e compartment was f i l l e d w i r h 350 m l o f 0 . 0 1 M p o t a s s i u m f e r r o c y a n i d e , K4Fe(CN)6-3H20. The c a t h o d e compartment was f i l l e d w i t h d i s - t i l l e d w a t e r , t o which a c i d (HC1) was added t o i n c r e a s e conduc- t i v i t y . The v o l t a g e was s e t a t 3 . 5 v o l t s D . C . and t h e c u r r e n t c o n t i n o u s l y m o n i t o r e d .

F u r t h e r s t u d i e s were made a t v a r y i n g t e m p e r a t u r e s by immers ing t h e c e l l i n a c o n s t a n t t e m p e r a t u r e w a t e r b a t h . T e m p e r a t u r e s '

r a n g e d from 25OC t o 50°C i n f i v e d e g r e e i n t e r v a l s . Amperage measurements were made a t v a r i o u s t e m p e r a t u r e l e v e l s .

Figu

22

!re prc- .1 in !ne liter x cyanid were e immersl and the densit;

etween s. Sam- times

se in f cells

at the I measur- 1 were :rom

j Were

'tments .e cath- Nlution n con-

t was

dis- onduc- urrent

ersing Jres rage

Recti Brid

Stirrer

Voltmeter

fier ge P, I Ammeter

Screen Anode

Variac

Figure 1 Bench Top Non-Membrane Electrolysis Cell

P i ! c 7 i I ’ l n i i t I ; c . ~ c i ~ c ~ r n t i o i i Ccll

T h e i c l l was dcs ig i i cd t o r u n a s a c o n t i n u o u s €low s y s t c m . A 10.00+.01 g r a i i i / l i t c r p o t a s s i u m f e r r o c y a n i d e ( K 4 F c ( C N ) 0 3 1 1 ~ 0 ) s o l u t i o n was p r e p a r c d aiici p l a c e d i n a h o l d i n g t a n k . t i o i i \\*as i nc t c rcd i n t o t h e c c l l a t v a r i o u s f l o w r a t e s f rom 1 5 0 ml/min t o 500 ml/inin t l i rougl i a f l o w m c t c r . The c e l l voltage 1i3s a d j u s t e d t o 3 . 5 v o l t s U . C . Ovc r i low samples were t a k e n p e r i o d i c a l l y a n d a n a l y z e d f o r f e r r i c y a n i d e . The c u r r e n t was m o n i t o r e d c o n t i n u o u s l y a n d t h e c e l l e f f i c i e n c y compared t o t h e t h e o r e t i c a l e f f i c i e n c y as computed from Faraday’ s Law.

.fi h i s s o l u .

24

t cm. A I * 3f120) t h i s s o l u from 1 5 0 ) I t a g e t a k e n

: n t was :d t o the

kiemb r a n e

Figure 2 Membrane Electrolysis Cell

1 Plexiglass Electrolyte Compartment

25

. .

u Kegenerated Ferricyanide

'l- 0 Cat ha de Powcr

I i 2 Exh

bQ

JJ

Drain -

aus t

- To Anode Power

Flowmeter i - e- Ferrocyanide

Figure 3 Pilot Plant Non-Membrane Electrolysis Cell

Power

?r

- so cyanid)

2 7

.--

Figure 4 Pilot P l a n t Electrolytic Cell

Ozone R e g e n e r a t i o n and D e s t r u c t i o n o f Complex Cyan ides

(Subprogram C)

Bench Top R c g e n e r a t i o n

One l i t e r o f a 1 O k . 0 1 g r a m / l i t e r p o t a s s i u m f e r r o c y a n i d e {S4Fe(CN)6-3H 01, was p l a c e d i n t h e r e a c t i o n column and t h c f l o w o f t h e ozone i a s s t r e a m i n t o t h e r e a c t o r a d j u s t e d t o 5 SCI;H. Saniplcs were t a k e n a t v a r i o u s t imes d u r i n g t h e o x i d a t i o n and a n a l y z e d f o r pH and f e r r i c y a n i d e . d e t e c t e d ( s m e l l e d ) above t h e s o l u t i o n s u r f a c e , t h e system was sliu t down.

A t t h e p o i n t ozone c o u l d b e

C o n s t a n t pH s t u d i e s were a l s o pe r fo rmed u s i n g t h e above method w i t h t h e a d d i t i o n o f pH m o n i t o r i n g and c o n t r o l ; c o n c e n t r a t e d h y d r o c h l o r i c a c i d was added d ropwise t o t h e column t o m a i n t a i n a c o n s t a n t pH. were r e c o r d e d w i t h e a c h sample . S o l u t i o n s were a n a l y z e d f o r f e r r o c y a n i d e and f e r r i c y a n i d e ; and ma te r i a l b a l a n c e s c a l c u l a t e d .

The volume o f a c i d u s e d and t h e time o f r e a c t i o n

P i l o t P l a n t R e g e n e r a t i o n

For t h e p i l o t p l a n t s t u d i e s , 50 g a l l o n s o f 30 g r a m / l i t e r po- t a s s i u m f e r r o c y a n i d e {K4Fe(CN)6 '3H20~ s o l u t i o n were p r e p a r e d and p l a c e d i n a h o l d i n g t a n k . The s o l u t i o n was pumped i n t o t h e r e a c t i o n column t h r o u g h a f l o w meter a t f low r a t e s f rom 5 0 - 1 5 0 ml/min. The ozone gas s t r e a m , c o n t a i n i n g a 2 % (by v o l - ume) ozone c o n c e n t r a t i o n , was i n t r o d u c e d i n t o t h e v e s s e l a t 5 SCFH t h r o u g h a s p a r g e r t u b e a t t h e bo t tom.

Samples were t a k e n a t s e l e c t e d time i n t e r v a l s and a n a l y z e d f o r f e r r o c y a n i d e , f e r r i c y a n i d e , and pH.

Bench TOD D e s t r u c t i o n

S t o r 4 Tank : Fred

Solut:

A 0 . 0 1 Iy s o l u t i o n o f p o t a s s i u m f e r r o c y a n i d e .{K4,Fe(CN)6*3H20) was p r e p a r e d and 5 0 0 m l p l a c e d i n a one l i t e r b e a k e r . a d j u s t e d w i t h H C 1 o r N a O H a s r e q u i r e d . Ozont

The pHwas

T h r e e r e a c t i o n schemes were i n v e s t i g a t e d . F i r s t , ozone was b u b b l e d i n t o t h e sample w i t h o u t pH a d j u s t m e n t o r t e m p e r a t u r e c o n t r o l . f e r r i c y a n i d e . r e a c t i o n . Second , ozone was b u b b l e d i n t o a h i g h l y a c i d i s i e d s o l u t i o n , u s i n g a s t e e l wool c a t a l y s t . The p r o c e d u r e was a s a b o v e , w i t h t h e a d d i t i o n o f 5 grams o f s t e e l wool and 2 0 m l o f H C 1 t o t h e s o l u t i o n b e f o r e ozone was i n t r o d u c e d . T h i r d , t h e s o l u t i o n was a c i d i f i e d w i t h 20 m l H C 1 and h e a t e d . When t h e d e s i r e d t e m p e r a t u r e was r e a c h e d , ozone was i n t r o d u c e d i n t o t h e s o l u t i o n . Samples were t a k e n p e r i o d i c a l l y and a n a l y z e d f o r f e r r i c y a n i d e .

Samples were t a k e n p e r i o d i c a l l y and a n a l y z e d f o r Tempera tu re and pH were r e c o r d e d t h r o u g h o u t t h e

The t e m p e r a t u r e s s t u d i e d r a n g e d from 70'C t o 90°C.

E

2 8

. h e flow lcI:iI. , and 'uld be m was

method ated intain reaction for

ulated.

P O - ared nto rom y vol- at

zd for

ras :ure )r it the 'ied as 11 of the he o the O O C .

mide

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F 1 ow Meter

- I i

Storage Tank for Fresh

Solution

n

7 k

- E x h a u s t G a s e s t o hood

f Sump Pump ,

Plexiglass Column

Ozone from Generator - li

Figure 5 Pilot Plant Ozone Regeneration Cell

4 I Storage Tank for

Regenerated Solution

I

Figure 6 Laboratory Ozone Generator and Air Preparation Systel

30

F i g L r a 7 Pilot Plant Ozonation o r Chlorination CelL

31

Removal o f Heavy Meta l Complex Cyan ides

(Subprogram D )

P r e c i p i t a t i o n

F e r r o - a n d f e r r i c y a n i d e p r e c i p i t a t e s were formed from a s o l u t i o n c o n t a i n i n g 750 mg/l of t o t a l complex iron c y a n i d e a s F e ( C N ) 6 . Pr imary t e s t i n g was conduc ted a t 2 O 0 C + 1 " C . Secondary t e s t s were made a t 1 6 ' C , 2 6 O C and 4 6 ' C . The i n i t i a l pH o f a l l s o l u - t i o n s was a d j u s t e d t o 8 . 0 k . 1 . For t h e pH s t u d i e s , , i n i t i a l v a l u e s o f 2 . 0 , 6 . 0 , 8 . 0 , and 1 1 . 0 were i n v e s t i g a t e d . E i t h e r hydro - c h l o r i c a c i d o r 2 . 5 N sodium h y d r o x i d e was u s e d t o a d j u s t t h e PH*

7 5 0 ml of s t o c k complex c y a n i d e s o l u t i o n was p l a c e d i n g o n e l i t e r b e a k e r and t h e pH a d j u s t e d as r e q u i r e d . was t h e n p l a c e d on t h e m u l t i p l e s t i r r e r and s t i r r e d a t 100 rpm. Using an u p r i g h t g r a d u a t e d p i p e t , t h e r e q u i r e d amount of heavy m e t a l s a l t s o l u t i o n was added t o form t h e p r e c i p i t a t e . The m i x t u r e was a l l o w e d t o s t i r f o r f i v e m i n u t e s , , a t which p o i n t t h e s t i r r i n g p a d d l e s were removed.

A d e f i n i t e l i n e o f s e p a r a t i o n e x i s t e d be tween t h e s u p e r n a t a n t and t h e c l o u d y l a y e r . A t time i n t e r v a l s of 5 , 1 0 , 20 and 30 m i n u t e s , t h e h e i g h t o f t h i s l i n e was measured from t h e botcom o f t h e r e a c t i o n v e s s e l and u s e d t o c a l c u l a t e s e t t l i n g r a t e s .

The s o l u t i o n

Twenty m i l l i l i t e r s amples were c o l l e c t e d a t a p o i n t one q u a r t e r i n c h below t h e s o l u t i o n s u r f a c e a t e a c h r e c o r d i n g o f s e t t l i n g t ime .

C e n t r i f u g a t i o n ( F o r e x a c t t e s t p r o c e d u r e see Appendix C)

The c e n t r i f u g a t i o n t e s t s were c o n d u c t e d u s i n g two f l o c c u l a n t s , N a l c o l y t e 6 7 0 and P u r i f l o c A - 2 3 , o v e r t h e c o n c e n t r a t i o n r a n g e o f 0 . 0 t o 1 0 . 0 mg/l by w e i g h t o f f i v e heavy metal i o n s ( F e + 2 , Mn+2, Cu ', Zn+y and Cd c o n d i t i o n s o f :

Tests we$ cond c t e d on+sach ) u n d e r

C o n s t a n t f l o w r a t e t h r o u g h t h e s y s t e m and v a r i a b l e c e n - t r i f u g e r o t o r s p e e d w i t h v a r i o u s f l o c c u l a n t c o n c e n t r a t i o n s .

C o n s t a n t r o t o r s p e e d and v a r i a b l e f l o w r a t e w i t h v a r i o u s f l o c c u l a n t c o n c e n t r a t i o n s .

One g a l l o n o f a 1 . 5 0 + 0 . 0 1 g r a m / l i t e r s o l u t i o n o f p o t a s s f u m f e r r o c y a n i d e [KqFe(CN)6'3H20] was p l a c e d i n a c a r b o y on a s t a n d above t h e l e v e l o f t h e c e n t r i f u g e ( F i g u r e 9 , page 3 5 ) . The pH o f t h e s o l u t i o n was a d j u s t e d t o 6 . 4 2 0 . 2 and t h e t e m p e r a t u r e 20°C+10C.

32

.ution U

G*

:S

,olu

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the

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-

ne n e avy e t rpm

.

an

t 30 tom

S

.

arte

r ing

nts, 'g e :h under

1- cions

IUS

i tand

f

pH !

35

i

A s t i r r e r was a r r a n g e d s u c h t h a t t h e b l a d e was be tween 2 and 3 i n c h e s above t h e bot tom of t h e c a r b o y , o p e r a t e d a t 100 rpm. A 10: e x c e s s o f heavy m e t a l s a l t s o l u t i o n , o v e r t h e s t o i c h i o - met r ic r e q u i r e m e n t , was added t o t h e ca rboy and t h e r e s u l t i n g s l u r r y agi:atcd Tor an a d d i t i o n a l f i v e m i n u t e s .

The c e n t r i f u g e was s t a r t e d and b r o u g h t t o 6500 rpm. f low of s l u r r y was i n i t i a t e d and t h e c o l l e c t i o n t u b e s f i l l e d . Flow was d i s c 0 n t i n u e . d and t h e c o n t e n t s o f t h e t u b e s a l l o w e d t o s t a b i l i z e f o r f i v e m i n u t e s a t 6500 rpm.

The " r o t o r s t u d y " was conduc ted by i n c r e a s i n g r o t o r s p e e d s t e p . wise from 6500 rpm t o 15 ,800 rpm and t h e n back t o 6 5 0 0 rpm. Flow th rough t h e c e n t r i f u g e d u r i n g t h i s s t u d y was c o n s t a n t .

The " f low s t u d y " was conduc ted by i n c r e a s i n g t h e s l u r r y f low r a t e t h rough t h e s y s t e m s t e p w i s e f rom 6 ml/min t o 2 0 0 ml/min and t h e n d e c r e a s i n g a g a i n t o 6 ml/min. t h i s s t u d y was c o n s t a n t .

For each o f t h e f i v e m e t a l i o n s , a f l o w s t u d y and a r o t o r study was conduc ted a t each o f t h e v a r i o u s f l o c c u l a n t c o n c e n t r a t i o n s , Samples were t a k e n a t each i n c r e m e n t o f f l o w r a t e o r r o t o r s p e e d .

Absorbance o f t h e samples was measured a t 2 2 0 m u ; an absorbance peak f o r f e r r o c y a n i d e . pended m a t e r i a l .

The g r a v i t )

The r o t o r s p e e d d u r i n g

.

T h i s measures b o t h d i s s o l v e d and s u s -

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35

C h l o r i n e D e s t r u c t i o n 'of Complex Cyanides

(Subprogram E )

Two a p p r o a c h e s t o c h l o r i n a t i o n ( o r h y p o c h l o r i n a t i o n ) were e v a l u a t e d : a h y p o c h l o r i t e s o l u t i o n and c h l o r i n e g a s .

For t h e f i r s t s e r i e s of e x p e r i m e n t s , 5 0 0 ml were added t o 5 0 0 ml o f 10.0+0.1 g r a m / l i t e r ' g a n i d e [K3Fe(CN)b] s o l u t i o n , The pH was ad Measurements were made o v e r t h e t e m p e r a t u r e m0O"C. Samples were t a k e n a t v a r i o u s t i m e s f e r r i c y a n i d e .

of Clorox b l e p o t a s s i u m f e r . j u s t e d t o 11. r a n g e o f 20°C

and a n a l y z e d

a c h r i - 0 + 1 . -

t o f o r

0.

For t h e sccor ld s e r i e s , c h l o r i n e g a s was bubb led i n t o one l i t e r of a 10.01tO.1 g r a m / l i t e r s o l u t i o n o f p o t a s s i u m f e r r i c y a n i d e [K3Fe(CN)6], w i t h and w i t h o u t t h e a d d i t i o n o f NaOH t o m a i n t a i n . t h e pH a t 11.0?1.0. Dur ing t h e r e a c t i o n , s amples were t a k e n p e r i o d i c a l l y f o r a n a l y s i s and t h e pH was m o n i t o r e d . These t e s t s were a l s o conduc ted o v e r t h e t e m p e r a t u r e r a n g e o f 2 0 ° C t o 100°C. The a n a l y s i s o f t h e c h l o r i n a t e d samples r e q u i r e d t h e a d d i t i o n o f sodium s u l f i t e (Na2SO3) t o "quench" o r s t o p t h e r e a c t i o n by

I - I n e u t r a l i z i n g t h e c h l o r i n e .

I

C

36

e r e

b l e a c h f e r r i - 1 1 . 0 + 1 . 0 . 3°C t o zed f o r

i e l i t e r 3n ide n a i n t a i n t a k e n

l e s e t e s t ! t o l o o o c ,

l d i t i o n : t i o n by

. . . . . . . .. . . . .

M c t h o d o f C o s t A n a l y s i s

i:or ; i l l c u s t ; t t1 ; i lys i s ~ 0 1 . k ;i s i n g l c I i y p o t h c t i c a l p r o c e s s i n g lll;lclli~ic \vas u s e d . Tlic c h o s e n machine was a combined a v c r a g e of v a r i o u s p r o c e s s e s . These i n c l u d e : Kodacolor Color N e g a t i v e ( p r o c e s s C - 2 2 ) , E k t a c o l o r C o l o r Paper ( p r o c e s s E k t a p r i n t C), EktaChrOnle R e v e r s a l F i l m ( p r o c e s s E - 4 ) and Ektachrome Pape r ( p r o c e s s E k t a p r i n t - R ) . The f o l l o w i n g t a b l e shows t h e f l o w r a t e , c o n c e n t r a t i o n of sodium f e r r i c y a n i d e , and a p p r o x i m a t e cos t o f t h e i n d i v i d u a l b l e a c h e s and t h e "combined ave rage" .

R e p l e n i s h e r R e p l e n i s h e r Na3Fe ( C N ) 6 Bleach

Flow R a t e C o n c e n t r a t i o n 'Cost Proc.ess (m 1 / m i n) ( g / U $/IO0 g a l

Xodacolor (C- 2 2 ) 275

E k t a c o l o r Pape r (Ek t a p r i n t - C 260

Ektachrome Fi lm ( E - 4) 1 1 5

Ektachrome Pape r (Ek t a p r i n t - R) 150

Combined Average 2 0 0

25 $ 87.00

25 $ 48.00

120 $238.00

30

50

$ 72.00

$111.00

During f i l m p r o c e s s i n g a b o u t one s i x t h o f t h e r e p l e n i s r e r f e r r i c y a n i d e i s assume) t o b e r educed t o f e r r o c y a n i d e . An a v e r a g e y e a r was t a k e n as 260 d a y s a t e i g h t h o u r s p e r day . A "combined ave rage" machine was assumed t o h a n d l e 800 rolls of f i l m p e r day .

37

I

I SEC'1'ION VI

DISCUSSION OF IIESULTS

I ~

Analytical (Subprogram A )

Iodometric Determination of Ferricyanide

The concentration of sodium ferricyanide can be determined by reaction of ferricyanide with iodide ions forming f r e e i o d i n e , then titration of the iodine with standardized sodium thiosulfate. The reactions involved are as follows:

2 Fe(CN)6-3 + 2 I- -+ 2 Fe(CN)g-4 + I 2 ( 2 8 )

Table I (page 40) shows the analysis of six samples of pqre sodium ferricyanide of various concentrations compared to the actual concentrations. The average deviation of the samples from the actual values is 0.48 g / l .

The test procedure was applied to an actual bleach solution from a Kodachrome K-12 processor to determine the precision of the test on a real sample. Seven analytical measurements of the same sample produced an average deviation of 0.83 g / 1 and a standard deviation of 1.02 g/l. Expressed as a percentage, the standard deviation is 0.95 percent of the average value for the concentration of sodium ferricyanide in a real bleach. This method of determining sodium ferricyanide concentration f o r quality control of the photographic bleach is satisfactory. not sufficiently accurate for use in pollution control.

It is

Cerimetric Determination of Sodium Ferrocyanide

The concentration of sodium ferrocyanide can be determined from it oxidation in acid solution by means of a standardized ceric sulfate solution with sodium diphenylamine-sulfonate as an indicator; the reaction being:

~ e + 4 + Fe(CN)6-4 -+ ~ e + ~ + Fe(CN)6 (30 1 -3

Table I1 (page 41) shows the results of five samples using this method of analysis. The titration end point is difficult to observe; especially on used photographic bleach solutions. This data shows an average deviation of k2 .13 g / l . This test method is also acceptable for use as a rapid quality control measurement, but is not satisfactory for pollution control use.

39

TABLE I

S amy 1 e

A

B C

D

E

F

Sodium Ferricyanide (Na3Fe(CN),6) Concentrations

as Determined by Iodometric Titration Methods Sod

Sodium Ferricyanide Concentration Sample

Actual (g/ 11 Measured ( g / l )

1 0 . 0 0

1 0 . 0 0

2 0 . 0 0

3 0 . 0 0

3 5 . 0 0

A 1 0 . 2 6

8 . 4 8

2 0 . 0 4

B

C

3 0 . 1 6

3 4 . 5 6

50.00 4 9 . 5 5

D

E

40 L

i

TABLE I 1

Sodium F e r r o c y a n i d e (Na4Fe ( C N ) 6 1 0 H 2 0) C o n c e n t r a t i o n as

Dctcri:iiiicJ by Ccyimctric Titration Method

Sodium F e r r o c y a n i d e C o n c e n t r a t i o n

A c t u a l ( g / l ) Measured ( g / l )

2 0 . 0 0 19.94

30.00

50.00

70.00

80 .00

3 1 . 1 1

52.20

66 .04

76.45

l )c te r111innt io~z o f F e r r o c y a n i d e u s i n g S p c c t r o p h o t o m e t r i c masure,

nicnt a t 7 0 0 nm.

The c o n c e n t r a t i o n o f sodium f e r r o c y a n i d e (Na4Fe (CN)6*10 H20) 3 c a n be d e t e r m i n e d by a d d i n g f e r r i c i o n t o form Fe4 [Fe(CN)6]

P r u s s i a n B lue ; and m e a s u r i n g t h e a b s o r b a n c e o f t h e s o l u t i o n at 7 0 0 m p ( F i g u r e 1 0 , page 4 3 ) .

F i g u r o 11 (gage 4 4 ) and F i g u r o 12 (page 4 5 ) show t h e absorb.. a n c e - - c o n c e n t r a t i o n c u r v e s a t 700 mp f o r t h e f e r r o c y a n i d e con. c e n t r a t i o n r a n g e s 0-1 mg/l and 0 -25 mg/ l , r e s p e c t i v e l y . These c u r v e s show t h a t o v e r t h e above c o n c e n t r a t i o n r a n g e s , t h e r e - l a t i o n s h i p i s l i n e a r .

A l e a s t s q u a r e s a n a l y s i s was made on b o t h o f t h e above f i g u r s, For t h e c o n c e n t r a t i o n r a n g e 0-25 mg/l f e r r o c y a n i d e ; Fe(CN)6’ .

as = 0 , 0 0 3 6

- .

2

a = 0.0522 1 S t a n d a r d E r r o r o f Absorbance S = k O . 0 0 8

Y ‘

F o r t h e c o n c e n t r a t i o n r a n g e 0 - 1 mg/l f e r r o c y a n i d e ; Fe(CN)6 - 4 a, = 0 , 0 0 6 3

a l = 0.0522

S t a n d a r d E r r o r o f Absorbance S = k O . 0 0 1 0 2 Y

T h i s method o f a n a l y s i s f o r f e r r o c y a n i d e i s e x t r e m e l y a c c u r a t e ; k

and can b e used t o d e t e r m i n e t h e c o n c e n t r a t i o n o f f e r r o c y a n i d e f i n t h e r a n g e o f 0 . 2 t o 0 . 4 mg/l a s r e q u i r e d f o r p o l l u t i o n con- : t r o l measurements .

D e t e r m i n a t i o n o f F e r r i c y a n i d e u s i n g S p e c t r o p h o t o m e t r i c Measure-;. l

ment a t 4 1 7 XI.,.

The COI:<.L l L L ~ . , s B . J ~ , U i u i n f e r r i c y a n l d c can be d e t e r m i n e d d i r e c t l y b y ~ l i ~ L I s ~ r c l , r c ~ ~ t o f i t s a b s o r b a n c e a t 4 1 7 m u . The f o l l o w i n g a b s o r b a n c e - c o n c e n t r a t i o n v a l u e s were o b t a i n e d f o r sodium f e r r i c y a n i d e a t 4 1 7 mp:

u c rj P h 0 m P 4

Fi

WAVELENGTH ABSORBANCE

500 ,049 6 20 .067 640 ,06

6 8 0 , 0 9 4 700 ,095 7 2 0 .09 5 7 3 0 .09 5 7 4 0 ,093

7 8 0 ,083 800 ,077

660 ,087

7 6 0 . o m

0 -600 620640 660 680 700 720 740 760 780 800 Wavelength, m p

Figure Q O Absorbance Curve for Prussian Blue

.O 45

.04 0

,03 5

.03 0

.O 25 0

(d 2 ,020 P k 0 P v1 ,015

,010 <

.oo 5

0 o a I ,2 .3 .4 .5 .6 .7 .8 9 ID

Total Fe(CN)6 Concentration mg/l

Figure 11 Absorbance--Total F e ( C N ) 6 Concentration from

0.0 to 1.0 mg/liter at 700 mp

4 4

1.2

1 .I

1 .O

.9

,8

.7

.6

.5 Q, u cd .4

v, O .3 P k

P 4 .2

.I

0 0 2 4 G 8 IO 12 14 16 18 20 22 24 26 28

lotal Fe(CN) Concentration (mg/l) t 6 ID

b E:

Figure 12 Absorbance--Total Fe(CN) 6 Concentration From

0.0 to 25.0 m g / l a t 7 0 0 mP

4 5

Con c e 11 t I* a t i o 11 of Sod i uln 1: c 1' r i cy a n i de

gm/ 1

' 0 , 4 2 9 0 . 2 7 ' 3 0 . 2 1 5 0 . 0 8 6 0 . 0 4 3 0 . 0 0 8

Absorbancc

1 . 5 1 2 1.000

0 . 3 1 6 0 . 1 6 0 0 , 0 2 6

0 . 7 ~ 8

A l e a s t s q u a r e s a n a l y s i s on t h i s d a t a r e s u l t s i n t h e f o l l o w i n g :

a, = 0 . 0 1 6

a = 3 . 5 0 1 S t a n d a r d E r r o r o f Absorbance S = 5 0 . 0 6 3 1

Y Th i s method i s s a t i s f a c t o r y f o r m e a s u r i n g t h e c o n c e n t r a t i o n o f sodium f e r r i c y a n i d e i n s o l u t i o n s c o n t a i n i n g o n l y f e r r o - a n d f e r r i - c y a n i d e . I t i s n o t s u i t a b l e f o r p h o t o g r a p h i c b l e a c h s o l u t i o n s (due t o c o l o r i n t e r f e r e n c e ) o r o t h e r s o l u t i o n s where t h e concen- t r a t i o n i s l e s s t h a n 1 0 . 0 0 m g l l a s Na3Fe(CN)6

D e t e r m i n a t i o n o f Sodium F e r r i c y a n i d e u s i n g S p e c t r o p h o t o m e t r i c

Neasurement a t 4 6 0 . 5 m u .

The c o n c e n t r a t i o n o f sodium f e r r i c y a n i d e c a n be d e t e r m i n e d i n a h i g h e r c o n c e n t r a t i o n r a n g e 0 - 4 gm/l by d i r e c t measurement of i t s a b s o r b a n c e a t 4 6 0 . 5 m P . The f o l l o w i n g a b s o r b a n c e - c o n c e n t r a - t i o n v a l u e s were o b t a i n e d f o r sodium f e r r i c y a n i d e a t 460 .5 m P e . _

C o n c e n t r a t i o n Sodium F e r r i c y a n i d e

gm/ 1

2 . 6 6 1 . 7 0 1 . 3 3 1 . 3 3 0 . 8 5 0 . 4 2 6 0 . 3 4 5 0 . 2 5 5 0 . 1 7 0 0 . 0 8 5

4 6

Absorbance

0 . 6 7 3 0 . 4 3 5 0 . 3 3 7 0 . 3 3 5 0 , 2 2 2 0.115 0 , 0 9 5 0 . 0 7 0 0 , 0 5 0 0.024

ri-

n-

l e a s t s q u a r c s a n a l y s i s r e s u l t s i n t h c f o l l o w i n g :

a. = 0.0056

= 0 . 2 5 1 "1 S t a n d a r d E r r o r o f Absorbance S = k O . 0 1

Y T h i s method i s s i m i l a r t o t h e measurement a t 4 1 7 mp,but c a n b e used i n a h i g h e r c o n c e n t r a t i o n r a n g e .

Nitropruss i ( I C T I I ~ ~ ~ I - ! ~ ; ~ ~ ( I ~ c I ~ c ( I ; O ( C N ) g ~ ~ ) - -

I t NJS i oL ; ! i J L\:L:J), i 11. ; ; l i s w o r k t h a t m a t e r i a l b a l a n c e s u s i n g s p e c t r o s c o p y r e su l t cc i i n an o v e r a l l complex c y a n i d e i n c r e a s e o f t h e t r e a t e d s o l u t i o n . I t was s u s p e c t e d t h a t some i n t e r f e r - ence o f a n i n t e r m e d i a t e o x i d a t i o n p r o d u c t be tween f e r r o c y a n i d e and f e r r i c y a n i d e was t h e c a u s e o f a n i n c r e a s e d abso rbance o f t h e t r e a t e d s a m p l e s . The n i t r o p r u s s i d e i o n was p roposed a s t h e i n t e r m e d i a t e . ( 1 6 ) S e v e r a l t e s t s were c o n d u c t e d u s i n g f e r r o - and f e r r i c y a n i d e w i t h a known q u a n t i t y o f n i t r o p r u s s i d e (Tab le 111, page 4 8 ) . I f t h i s i n t e r m e d i a t e had a g r e a t e r a b s o r b t i v i t y a t t h e a b s o r b a n c e r e a d i n g s f o r f e r r o - a n d f e r r i c y a n i d e , i t would e x p l a i n t h e m a t e r i a l b a l a n c e problem. The r e s u l t s ( T a b l e IXX) c o n f i r m t h e i n t e r f e r e n c e o f t h i s compound by showing t h a t n i t r o - p r u s s i d e w i l l p r o d u c e t h e e f f e c t o f a h i g h e r complex c y a n i d e c o n c e n t r a t i o n t h a n i s p r e s e n t .

47

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48

E l e c t r o l y s i s o f F e r r o c y a n i d e s

8 (Subprogram B) 1 b h

~ o n - i \ l c ~ n b r a n e C e l l ; Ambient Tempera tu re 4

~ 1 1 c e l l s p r e p a r e d f o r t h i s s t u d y were compared t o a t h e o r e t i c a l c e l l d e f i n e d t o a c c o u n t f o r t h e anode r e a c t i o n o n l y . tile v a r i a b l e s i n v o l v e d t o c u r r e n t and t i m e , a l l c e l l s were cha rged I q i t h s o l u t i o n s of i d e n t i c a l f e r r o c y a n i d e c o n c e n t r a t i o n . A t any c u r r e n t t h e r e i s a t ime i n which a t h e o r e t i c a l c e l l p r o d u c e s a 1 0 0 % c o n v e r s i o n ( f e r r o - t o f e r r i c y a n i d e ) . Thus , t h e c e l l s c a n b e compared on a d i m e n s i o n l e s s t i m e s c a l e d e f i n e d a s a p e r c e n t of t h e t h e o r e t i c a l c o n v e r s i o n t i m e .

To l i m i t

e =t (31 ) t C

l a e r e 0 = P e r c e n t of t h e o r e t i c a l c o n v e r s i o n

t = A c t u a l t ime o f t h e r e a c t i o n ( m i n u t e s )

t c = T h e o r e t i c a l t ime f o r 1 0 0 % c o n v e r s i o n ( m i n u t e s )

The p e r c e n t o f c o n v e r s i o n by e a c h c e l l a t 6 = 1 was d e s i g n a t e d as t h e e f f i c i e n c y o f t h e c e l l .

F i g u r e 13 (page 5 0 ) shows t h e r e l a t i o n s h i p be tween t h e con- v e r s i o n of f e r r o c y a n i d e and t h e p e r c e n t o f t h e o r e t i c a l c o n v e r s i o n , f o r v a r i o u s c a t h o d e t o anode c u r r e n t d e n s i t y r a t i o s ( C D R ) . A s t h e c u r r e n t d e n s i t y r a t i o i n c r e a s e s , c o n v e r s i o n i n c r e a s e s . T h i s conf i rms t h e t h e o r y t h a t i n c r e a s i n g hydrogen o v e r v o l t a g e o f t h e ca thode (hydrogen e v o l u t i o n p e r u n i t a r e a o f c a t h o d e ) i n c r e a s e s t h e o v e r a l l o x i d a t i o n e f f i c i e n c y r e l a t i v e t o F a r a d a y ' s Law. Although CDR's <1 were e v a l u a t e d e x p e r i m e n t a l l y , t h e y were n o t i n c l u d e d i n F i g u r e 13 b e c a u s e d e c o m p o s i t i o n of t h e complex o c c u r s . No p i l o t p l a n t c e l l was , t h e r e f o r e , d e s i g n e d w i t h a C D R < l .

F igu re 1 4 (page 5 1 ) compares t h e c u r r e n t d e n s i t y r a t i o and ' c o n v e r s i o n a t 0 = 1. A t t h i s Q v a l u e , t h e maximum i n c u r r e n t

usage h a s b e e n r e a c h e d , For 0< 1, f u l l c o n v e r s i o n h a s n o t b e e n ' a t t a i n e d . For 0> 1, power e f f i c i e n c y i s r e d u c e d i d u e t o an i n -

crease i n t h e s e c o n d a r y c a t h o d e r e a c t i o n r e l a t i v e t o t h e p r i m a r y anode r e a c t i o n . Using t h e method of l e a s t s q u a r e s , t h e . fo l low- i n g e x p r e s s i o n was de r ived . '

(32$ 1 .152 -1 C o n c e n t r a t i o n of F e r r o c y a n i d e

In X, = [-0.744€DR 1 Where X O = c o n v e r s i o n = 1 - a t 0 = 1 . 0

I n i t i a l c o n c e n t r a t i o n i e r r o c y a n i d e

CDR = Cathode- to-Anode C u r r e n t D e n s i t y R a t i o

S t a n d a r d d e v i a t i o n ( a v e r a g e e r r o r ) i s 4 . 3 2 9

49

0 a *d c cb x u 0 k k 0 F4

3 c) c, k 0 > c 0 u c 3

Q d 0 V k Q) a

100

95

9 0

85 8 0

75

70

6 5

6 0

5 5

5 0

4 5

40

35

3 0

2 5

20

15

10

5 0 I

.20 ,4 0 .60 .8 0 I .oo 1.20 1 4 0 0

P e r c e n t T h e o r e t i c a l Conversion

F i g u r e 1 3 : ~ , ' . , 1 I 1 (-t~:-.i:~.:cJ F c r r o c y a n i d c - - P e r c e n t T h e o q t i c a l

,\dn-I\:cinbrane E l e c t r o l y s i s a t V a r i o u s Convcl-s i o i i

C u r r e n t D e n s i t y R a t i o s

1.4 0

1

I I 0 W

0 .2 .4 .6 .8 LO 1.2 1.4 1.6 1.8 2.0 24 2.6 2.6 3.0 3,2 La& c m

Figure 14 Effect of Current Density Ratio on Conversion

of Ferrocyanide to Ferricyanide in an Electrolytic Cell

For any r e q u i r e d c o n v c r s i o n , u s e of t h e abovc e x p r e s s i c n w i l l show t l ic niaximum c u r r e n t d e n s i t y r a t i o f o r optimum c u r r c n t u t i 1 i z a t i on .

F i g u r e 1 5 (page 5 3 ) shows t h e r e l a t i o n s h i p be tween t h e c u r r c n t d e n s i t y r a t i o and t h e i n c r e a s e i n o x i d a t i o n r a t e w i t h t empcra - t u r e , o v e r t h e r ange from 2 5 ° C t o 6 0 ° C . of a n a l y s i s p roduced t h e f o l l o w i n g e q u a t i o n :

The l e a s t s q u a r e s mcthod

1,839 - ,0281 ( C D R ) A T

Where A R = P e r c e n t change i n r a t e

A T = Change i n t e m p e r a t u r e (C")

( 3 3 )

S t a n d a r d D e v i a t i o n i s 3 . 6 0 %

Using t h i s e q u a t i o n , t h e r a t e i n c r e a s e c a n be c a l c u l a t e d f o r a s e l e c t e d c u r r e n t d e n s i t y r a t i o and t e m p e r a t u r e above 25°C.

The Membrane C e l l : Ambient Tempera ture

?'he membrane c e l l s were compared u s i n g t h e p e r c e n t o f t h e o r e t i c a l c o n v e r s i o n , 0 , i n t h e same manner a s was done f o r t h e non-mem- b r a n e e l e c t r o l y t i c c e l l s . F i g u r e 1 6 (page 5 4 ) shows t h e r e - l a t i o n s h i p be tween t h e p e r c e n t t h e o r e t i c a l c o n v e r s i o n and t h e a c t u a l c o n v e r s i o n i n t h e membrane c e l l . I t was found t h a t t h e membrane c e l l was a b l e t o a f f e c t n e a r l y 1 0 0 % c o n v e r s i o n o f f e r r o - c y a n i d e t o f e r r i c y a n i d e . D e v i a t i o n s of t h e a c t u a l c u r v e from t h e t h e o r e t i c a l c u r v e were p r i m a r i l y due t o v a r i a t i o n s i n t h e c u r r e n t w i t h time. As t h e r e a c t i o n p r o c e e d e d , t h e c u r r e n t de-' c r e a s e d s l i g h t l y due t o t h e d e c r e a s e i n f e r r o c y a n i d e c o n c e n t r a t i o n . T h i s was compensa ted f o r i n t h e a n a l y s i s by u s i n g t h e a v e r a g e c u r r e n t t o c o n s t r u c t t h e F a r a d a y ' s Law p l o t .

The e l e v a t e d t e m p e r a t u r e s t u d i e s were c o n d u c t e d be tween 2 5 O C and 50°C. The r e s u l t i n g r e l a t i o n s h i p be tween c u r r e n t and temp- e r a t u r e a t a c o n s t a n t a p p l i e d p o t e n t i a l i s shown i n F i g u r e 1 7 (page 5 6 ) . The e q u a t i o n f o r t h e s l o p e o f t h i s curve was f o u n d t o b e :

Where A I = change i n c u r r e n t (amps)

A T = change i n t e m p e r a t u r e ("C)

No change i n t h e f i n a l c o n v e r s i o n ( = l o o % ) r e s u l t e d a t t h e e l e - v a t e d t e m p e r a t u r e .

5 2

F: b, V

U .rl c,

c, c Q, u k Q P( v

t

od

i

ical -

e rro-

- - ation,

!? - Ind

8 -

3 .o

2.5

2.0

I .5

I ,O

.5

0

Figure 15 Effect of Current Density Ratio on Ferrocyanide .-

Oxidation Rate for Non-Membrane Electrolytic Cell

53

. -- . . . . . . . . . I I 1 I I

0 e,

Q, 3 .rl c rd x U 0 k !4

a, c4 rw 0

VI c C .d VI k a, > c 0 u r( tu U .d c, Q, k 0 Q, c

i- a c cd

r(

6 3 c, u < Q,

.G e,

w 0

c: 0 v, .d k (3 a E 0 U

9 r(

0) k 3 M

.rl c4

d r( Q) u u .rl tJ x 4 0 k e, U a, r(

w Q, a h fi 0 c 03 k

D E Q,

rd

c .rl

a w . v i

c rj x U

.rl k k Q) c4

54

,3 5

.3 0

E 2.20

.IO

Temper a ture ("C)

Figure 17 Current-Temperatute Relationship for a Membrane

Type Electrolytic Cell

!

The ca rbon anodes w e r e found t o flake and decompose during t h e r e a c t i oii . P i l o t P l a n t C e l l

A c o n t i n u o u s f l o w e l e c t r o l y t i c o x i d a t i o n c e l l was d e s i g n e d from t h e r e s u l t s o f t h e bench t o p work on t h e non-membrane c e l l . A c e l l t h a t would p roduce a 9 6 % c o n v e r s i o n o f f e r r o c y a n i d e t o f e r r i - c y a n i d e was c h o s e n . From e q u a t i o n (32 ) i t was found t h a t a c u r r e n t d e n s i t y r a t i o o f 2 0 . 3 t o 1 . 0 would p r o d u c e t h i s c o n v e r s i o n w i t h t h e l e a s t amount o f power l o s s .

T a b l e I V (page 5 7 ) i s a compar i son of t h e a v e r a g e r e s u l t s o f t h e p i l o t e l e c t r o l y t i c c e l l s t u d i e s w i t h r e f e r e n c e t o t h e t h e o r e t i c a l c o n v e r s i o n (computed f r o m F a r a d a y ' s Law). The a c t u a l v e r s u s t h e t h e o r e t i c a l c o n v e r s i o n a g r e e s w e l l a t t h e h i g h e s t f l o w r a t e , b u t t h e r e l a t i o n s h i p d e c r e a s e s w i t h d e c r e a s i n g f l o w . D e c r e a s e s i n c e l l c o n v e r s i o n e f f i c i e n c y from t h e d e s i g n maximum of 9 6 % a r e a t t r i b u t e d t o :

- 1 , ~ , . . L t i c s i n anode c y l i n d r i c a l s h a p e

- p o i n t s o ~ 1 r c c s o f h i g h c u r r e n t d e n s i t y on anode

E x t e r n a l a g i t a t i o n , e f f e c t e d by b u b b l i n g a i r t h r o u g h t h e co lumns , produced n o . n o t i c e a b l e change i n c e l l c o n v e r s i o n . hydrogen e v o l u t i o n a t t h e c a t h o d e p roduced s u f f i c i e n t a g i t a t i o n f o r b o t h e l e c t r o d e s .

A p p a r e n t l y ,

C o s t A n a l y s i s f o r E l e c t r o l y t i c R e g e n e r a t i o n o f B leach

F o r an a v e r a g e p r o c e s s i n g mach ine , b l e a c h r e g e n e r a t i o n w i l l b e c a r r i e d o u t on a c o n t i n u o u s flow b a s i s w i t h t h e r e q u i r e d f e r r i - c y a n i d e a d d i t i o n and pH a d j u s t m e n t a f t e r r e g e n e r a t i o n . S i n c e o n e - s i x t h o f t h e f e r r i c y a n i d e i s c o n v e r t e d t o f e r r o c y a n i d e d u r i n g t h e b l e a c h i n g p r o c e s s , t h a t amount must b e r e g e n e r a t e d . E l e c t r o - l y t i c a l l y , t h a t r e q u i r e s 4 4 amperes /hour , p e r e i g h t hour day on t h e "combined ave rage" machine o v e r f l o w . A p r o d u c t i o n f l o w s c h e m a t i c f o r t h e e l e c t r o l y t i c sys t em i s shown i n F i g u r e 1 8 ( p a g e 59 ) . A summary o f equipment c o s t ' e s t i m a t e s f o l l o w s :

56

i o n u i l d r a t - e o f r r o - ferric d i z e d it on

h e

rom A ferri- current i th

f the tical the but in 2

imns , 7 9

ion

le i-

iring :tro- on

'age

TABLE IV

CONVERSION EFFICIENCY OF

PILOT PLANT NON-MEMBRANE ELECTROLYTIC CELL

(Initial Solution Concentration:

(Applied Voltage: 5 . 5 VDC

Applied .Flow Rate Current (m 1 /mi n) (amperes) .

300

2 0 0

150

300

5 . 2

5 . 0

5.0

6.0

57

5.03 g / 1 Fe(CN),-4)

Temperature: Ambient)

Calculated Experimental Theoretical Conversion Conversion

(%) (Faraday's Law) (9)-

42.9 4 1 . 0

5 5 . 5

56 .2

4 6 . 2

6 5 . 5

8 7 . 4

47.1

Equipment

E l e c t r o l y t i c c e l l w i t h pumps f o r r e c i r c u l a t i o n

50 g a l l o n p o l y e s t e r tank

Mixer 2 hp , r u b b e r c o a t e d s t e e l

pH c o n t r o l l e r w i t h p r o b e , s o l e n o i d and m e t e r i n g v a l v e

Labor and ma in tenance ( e s t i m a t e d a t 1 0 % i n s t a l l e d c o s t )

c o s t - $1 ,500

$ 1 0 0

$ 950

$3,000

$ 555

T o t a l $ 6 , 1 0 5 ,

C a l c u l a t e d p r e s e n t b l e a c h c o s t p e r 8 h r . day : C o s t of E l e c t r o l y t i c Equipment ( p e r day f o r 1 0 y e a r amor t iza t io$ :$Z.18 Savings f o r a 9 0 % b l e a c h r e c o v e r y : Dai ly s a v i n g s = D a i l y b l e a c h s a v i n g s - D a i l y Cost o f Equipment =

Sav ings p e r r o l l @800 r o l l s / d a y = 2 . 9 4 / r o l l

$28 .20

$25 .40

$ 2 5 . 4 0 - $ 2 . 1 8 = $23.22

E

sa

Sys t em

Bleach f rom Processor

E l e c t r o l y t i c Cell

S t i r r e r

bs Mixing and Replenishing Tank

er

Figure 18 Schematic of an Electrolytic Bleach Regeneration

System

5 9

Ozonc R c g c n c r a t i o n and Dccomposi t ion o f Complex Cyanides

(Subprogram C )

Bench T o p R c g c n e r a t i o n

The r e s u l t s o f two bench t o p r e g e n e r a t i o n s t u d i e s a r e shown i n F i g u r e 1 9 (page 6 1 ) . be tween p e r c e n t of c o n v e r s i o n ( F e r r o c y a n i d e t o f e r r i c y a n i d e ) and t ime o z o n a t i o n . s q u a r e s a n a l y s i s f o r ozone t r e a t m e n t w i t h o u t pH c o n t r o l . s l o p e i s d e s c r i b e d by t h e f o l l o w i n g e q u a t i o n :

These c u r v e s show a l i n e a r r e l a t i o n s h i p

The upper curve i s t h e r e s u l t o f a l e a s t The

&.here x = Co - C t ~0 a n d Co = C o n c e n t r a t i o n of ferrocyanide

C t = C o n c e n t r a t i o n of -ferrocyanide a t t i t

a t t = o

I n molar u n i t s , t h i s e q u a t i o n becomes

[GI = Molar ozone f l o w r a t e (moles /minu te )

The lower cu rve i n F i g u r e 1 9 i s t h e r e s u l t of a l e a s t s q u a r e s a n a l y s i s o f t h e o z o n a t i o n r e a c t i o n w i t h t h e pH c o n t r o l I e d be tween 5 . a K 2 S . XJ n o t i c e a b l e change i n t h e o x i d a t i o n r a t e o c c u r e d I C i z h 3: ~ i i t h o : ~ t p i i c o n t r o l . i r i c r zzse i:i ti;? JcLIrcc o f c o n v e r s i o n , when t h e pH was c o n t r o l l e d .

The o n l y e f f e c t n o t e d was a s l i g h t

S ince t h c L ; ~ c ; L ~ c ~ : i . - , . c ~ ~ a r e t y p i c a l f o r z e r o o r d e r r e a c t i o n s , t h e r a t e o f o s i d a t i o l l o f f e r r o - t o f e r r i c y a n i d e i s i t h ozone i s zero o r d e r w i t h r e s p e c t t o t h e f e r r o c y a n i d e c o n c e n t r a t i o n , o x i d a t i o n r e a c t i o n i s e x t r e m e l y r a p i d and t h e mass t r a n s f e r of ozone i n t o t h e s o l u t i o n i s t h e r a t e c o n t r o l l i n g p a r a m e t e r ,

The

6 0 I

de

de

les)

.60

IO Time, Min.

Figure 19 Conversion--Time Curve for Ozone Regeneration

61

' !

A compar ison o f t h e expe r in i cn ta l r e s u l t s and t h e s t o i c h i o - m e t r i c c q u a t i o n f o r t h e r e a c t i o n i s shown i n T a b l e V (page 6 3 ) . The s t o i c h i o m e t r i c e q u a t i o n i s g i v e n by:

2 Na4 Fe(CN)6 1 0 H 2 0 + 03 * 2 Na3 Fe(CN)6 + 2 NaOft + 02 4

19 H 2 0 ( 3 7 )

For e v e r y u n i t w e i g h t o f ozone , 2 0 . 2 u n i t w e i g h t s o f f e r r o - c y a n i d e a r e o x i d i z e d t o 1 1 . 7 u n i t weights of f e r r i c y a n i d e . (The u n i t of w e i g h t can be grams, pounds , t o n s , o u n c e s , e t c . ) . The o x i d a t i o n e f f i c i e n c y o f ozone (Tab le V page 63) i s approx- i m a t e l y 1 0 0 % f o r c o n c e n t r a t i o n s o f f e r r o c y a n i d e above a b o u t one gram p e r l i t e r . Below t h a t c o n c e n t r a t i o n , ozone i s r e - l e a s e d from t h e s o l u t i o n and t h e f e r r i c y a n i d e complex b e g i n s t o s l o w l y decompose. Thus, e x h a u s t e d ozone i s a n i n d i c a t o r o f t h e r e a c t i o n end p o i n t .

A s e r i e s o f t e s t s were c o n d u c t e d w i t h u s e d p h o t o g r a p h i c ' b l e a c h -

These t e s t s were conduc ted t o d e t e r m i n e t h e e f f i c i e n c y o f t h e c o n v e r s i o n o f f e r r o - t o f e r r i c y a n i d e , u s i n g ozone on a c t u - a l b l e a c h s o l u t i o n s . T a b l e V I (page 6 4 ) shows t h a t t h e r e i s no a p p a r e n t d e c r e a s e i n t h e ozone o x i d a t i o n e f f i c i e n c y f o r a c t u a l o r s i m u l a t e d p h o t o g r a p h i c b l e a c h e s .

' e s f rom Ektachrome ME-4 and Kodachrome K-12 p r o c e s s o r s .

A t p r e s e n t , t h e r e a r e a number of t e l e v i s i o n news p r o c e s s i n g l a b o r a t o r i e s and commercial p h o t o f i n i s h e r s u s i n g an ozone b l e a c h r e g e n e r a t i o n sys t em. Some o f t h e f e r r i c y a n i d e b l e a c h e s have b e e n r e g e n e r a t e d up t o f o r t y times w i t h no o b s e r v e d a d v e r s e e f f e c t s i n t h e b l e a c h i n g p r o c e s s .

P i l o t P l a n t R e g e n e r a t i o n

For a n a l y z i n g a c o n t i n u o u s f l o w column . r e a c t o r , t h e f o l l o w i n g r e l a t i o n s h i p was u s e d : ( 1 s )

Where G = Molar f l o w of g a s p e r s q u a r e f o o t o f r e a c t o r cross s e c t i o n moles

?vE

62

tu t 1 I t ry

TABLE V

COMPARISON OF EXPERIMENTAL RESULTS TO STOICHIOblETRIC CALCULATIONS

FERROCYANIDE OXIDATION WITH OZONE

Volume of Solution: 1 Liter

Concentration of Sodium Ferrocyanide:

Ozone Feed Rate 2.36 g/hr

11.45 g/1

Na3 Fe(CN)6 Conc. ( g / l ) Time of Reaction

Measured Theoretical Me as u r ed T h e o r e t i c a l

a u n 2: a d L? 0 e 0 3: 14

R w cn 3

k w 0

n

, " I C

6 4

Yo, Y1 - bloIcs of ozone per mole of air at the i n l e t and a t any point in the reactor, rcspectively.

L blolar upward flow of liquid per square foot o f reactor cross section Moles

ftzhr

X o , X1 = Moles of ferrocyanide per mole of water at the inlet (X ) and at any point in the reactor (XI?

ferrocyanide converted per mole of ozone = 2.0

b = Stoichiometric constant for moles of

For a very rapid reaction (ozone with ferrocyanide),the molar concentration of ozone at the outlet of the column is zero at equilibrium and under proper design. For convenience, the change in the concentration of ferrocyanide is expressed by the following convention:

Where C = The percent of conversion of ferrocyanide to ferricyanide

Upon substitution of equation ( 3 8 ) into equation ( 3 9 ) the relationship becomes:

G b

[Yo - YIJ = L X o C (40)

The liquid flow function L can be expressed as a constant (k) times the flow rate ( v ) , or

L = kv (41)

SubstitutjnE tI; i 5 i i i t o equation (40) yields

6 5

G [ Y o - Y1] = kv X o C b

(42)

For t h e s y s t e m under i n v e s t i g a t i o n , a l l t h e te rms i n equa - t i o n ( 4 2 ) e x c e p t f o r t h e l i q u i d f l o w r a t e u and C a r e con- s t a n t s t h e r e f o r e ;

o r

. T h i s shows t h a t t h e r a t e o f c o n v e r s i o n o f f e r r o c y a n i d e t o f e r r i c y a n i d e i s i n v e r s e l y p r o p o r t i o n a l t o t h e f l o w r a t e o f s o l u t i o n ( a t a c o n s t a n t ozone f e e d r a t e ) . The ozone o u t - p u t c o u l d n o t be v a r i e d w i t h t h e g e n e r a t o r employed i n t h i s s t u d y . A g r a p h i c a l i n t e r p r e t a t i o n of t h i s r e l a t i o n - s h i p and t h e e x p e r i m e n t a l d a t a a r e shown i n F i g u r e 2 0 , E x p e r i m e n t a l r e s u l t s a g r e e w e l l w i t h t h e t h e o r e t i c a l c u r v e , e x c e p t a t low f l o w r a t e s . The e r r o r a t t h e l o w f l o w r a t e s i s p r o b a b l y due t o f l u c t u a t i o n s i n f l o w . t h e p i l o t p l a n t work was ozone e x h a u s t e d f r o m t h e r e a c t i o n co lumns .

A t no p o i n t d u r i n g

C o s t A n a l y s i s f o r Ozone O x i d a t i o n o f F e r r o c y a n i d e t o F e r r i - 7 '

c v a n i d e f o r B leach Reuse

For r e g e n e r a t i o n of t h e "combined a v e r a g e " p r o c e s s o r f e r r i - c y a n i d e b l e a c h s o l u t i o n w i t h ozone , a t e n gram p e r h o u r ozone g e n e r a t o r i s r e q u i r e d , A flow s c h e m a t i c is shown i n F i g u r e 2 1 (page 6 8 ) .

66

67

P

HBr Tank

pti Controller

i E 2 Solenoid Valve I

1 1 - Bleach Feed

c P H Probe To

Storage

I Ozone

I Generator

1 I Sparger system

Figure 21 Flow Schematic of a Photographic Bleach

Regeneration System Using Ozone

6 8

process o v e r f l o w b lcac l l f l o w s t o t h c r e a c t o r vessel f o r ozonc l - c g e i i c r a t i o n . S i n c e a l l b l e a c h o s i n t h e p h o t o g r a p h i c p r o c c s s 31-e u s e d a t a pH r a n g e of 7 t o 9 , hydrobromic a c i d i s mc tc rcd i l l t o t h e v e s s e l t o c o n t r o l t h a t pH r a n g e . A f t e r r e g e n e r a t i o n t h e b l e a c h i s pumped t o a h o l d i n g t a n k f o r r e u s e . The c o s t o f equipment i s l i s t e d be low:

Equipment

Ozone Generator

c o s t

$ 2 , 0 0 0

Dry A i r Supply Sys tem $ 350

50 G a l l o n P o l y e s t e r Tank $ 1 0 0

Mixer : 2 lip r u b b e r - c o a t e J s ; t c c l

S p a r g e r s a i l c i .!< L * b , 1 , I : ) ;

Pumps

pH c o n t r o l l e r w i t h a u t o m a t i c p r o b e , s o l e n o i d and m e t e r i n g v a l v e

Labor and Main tenance ( e s t i n a t e d a t 1 0 % c o s t )

$ 550

$ 3 0 0

$ 250

$3,000

$ 6 5 0

T o t a l $ 7 , 2 0 0

C a l c u l a t e d p r e s e n t b l e a c h c o s t p e r 8 h o u r day : Cos t o f ozone equipment ( p e r day for 1 0 y e a r a m o r t i z a t i o n ) : Sav ings f o r a 9 0 % b l e a c h r e c o v e r y : $ 2 5 . 4 0 D a i l y s a v i n g s = D a i l y b l e a c h s a v i n g s - D a i l y C o s t equipment =

S a v i n g s p e r r o l l @ 8 0 0 r o l l s p e r day = 2,854 p e r r o l l

$28 .20 $2.50

$ 2 5 . 4 0 - $ 2 . 5 0 = $22 .90

Bench Top D e s t r u c t i o n

69

The r e s u l t s o f t h e ozone d e s t r u c t i o n a t ambien t t e m p e r a t u r e a r e shown i n Tab le V I 1 (page 7 0 ) . Only minor changes i n t h e t o t a l c o n c e n t r a t i o n o f complex c y a n i d e r e s u l t e d d u r i n g o z o n a t i o n of t h e s t a n d a r d b l e a c h s o l u t i o n a t room t e m p e r a t u r e . Dur ing a l k a - l i n e o z o n a t i o n , t h e s o l u t i o n became d a r k r e d a f t e r t h e s t o i c h i o - m e t r i c amount o f ozone ( f o r t o t a l c y a n i d e d e s t r u c t i o n ) had been added t o t h e s o l u t i o n .

'

t h e f o r m a t i o n o f s m a l l amounts o f t h e r e d F e r r a t e i o n ( F d = ) , s i n c e t h e c o l o r d i s a p p e a r e d upon a c i d i f i c a t i o n of t h e sampfe . F e r r a t e i o n i s s t a b l e o n l y i n b a s i c s o l u t i o n s .

T h i s c o l o r a t i o n may have b e e n due t o

1

/ I

7" i

I

TABLE V I 1

RESULTS OF OZONE DESTRUCTION OF FERROCYANIDE

AT AMBIENT TEMPERATURE

Initial Time of Final Complex Ozona t ion Complex Average

Concentration (min) Concentration PH

1. 6 . 3 5 r t 0 . 0 1 6 0

2 . 5 . 0 3 2 4 0

3. 5 . 0 3 3 0 0

4. 5 . 0 3 4 2 0

6 . 3 3 k 0 . 0 1 8.3?0*, 1

6 . 0 0 1 1 . 0

4 .85

4 . 8 6

4.0

11.0

5 . 2 . 1 2 3 0 0 1 . 7 7 7.0

Some deconipos i t ion o f t h e t o t a l complex o c c u r s u s i n g O Z O ~ C ~!y;der ;i~',

a c i d i c c o n d i t i o n w i t h a s t e e l w o o l c a t a l y s t . T h e r e a c t i o n k-.s

t h e complex c e a s e d . F o r p H < 3 . 0 , t h e complex i s o x i d i z e d t o ;Ton i lydroxide and c y a n a t e . The i r o n r e a c t s immedia te ly w i t h f r e e complex c y a n i d e t o form e i t h e r f e r r o u s f e r r o c y a n i d e o r f e r r l c f e r r o c y a n i d e . The r e a c t i o n c o n t i n u e s t o follow t h i s p a t h u n : i l no f r e e s o l u b l e complex c y a n i d e r e m a i n s .

I I

I I very s e n s i t i v e t o changes i n p l i . For p H > 3 . 0 , d e c o m p o s i t i o n c f

Hot a c i d i c o z o n a t i o n s were pe r fo rmed i n a t e m p e r a t u r e r a n g e o f 7 0 " - 9 0 ° C w i t h o u t t h e u s e of c a t a l y s t s . The pH was h e l d below 1 . 5 . F i g u r e s 2 2 (page 7 2 ) and 2 3 (page 73 ) show t h e resu1:s of t h o s e s t u d i e s . F i g u r e 2 2 shows t h e e f f e c t o f o z o n a t i o n t ime on t o t a l c o n c e n t r a t i o n of complex c y a n i d e ; i n c l u d i n g any r e - d i s s o l v e d p r e c i p i t a t e . a i r a l o n e i s a l s o shown. I n i t i a l l y , ozone o f f e r s no i n c r e a s e i n t h e d e s t r u c t i o n o f t h e complex o v e r s i m p l y h e a t i n g and a e r a t i n g under a c i d i c c o n d i t i o n s . However, a s t h e r e a c t i o n p r o c e e d s , o z o n a t i o n promotes a more comple t e d e s t r u c t i o n o f t h e complex.

F i g u r e 23 shows t h e r e l a t i o n s h i p be tween t h e c o n c e n t r a t i o n of

ozone f e e d r a t e . From F i g u r e s 2 2 and 23 , i t was c o n c l u d e d tl-.at t h e complex p r e c i p i t a t e s from s o l u t i o n f a s t e r t h a n i t decomposes.

The i r o n f e r r o c y a n i d e p r e c i p i t a t e s t a r t e d w i t h i t s c h a r a c t e r i s - t i c b l u e c o l o r b u t , as t h e r e a c t i o n p r o c e e d e d , i t t u r n e d t o a b l a c k g r a n u l a r p r e c i p i t a t e t h a t s e t t l e d r a p i d l y . The t r a n s i t i o n was g e n e r a l l y comple t e when t h e t o t a l c o n c e n t r a t i o n o f complex had been r educed t o t w o - t h i r d s o f t h e o r i g i n a l c o n c e n t r a t i o n . The p r e c i p i t a t e d i d n o t e x h i b i t c h a r a c t e r i s t i c s o f common i r o n f e r r o c y a n i d e m i x t u r e s . I t d i s s o l v e d o n l y above pH 1 3 . 0 . C o z - p l e x c y a n i d e s c o u l d b e e x t r a c t e d from t h e p r e c i p i t a t e w i t h con- c e n t r a t e d ammonium h y d r o x i d e w i t h o u t chang ing t h e p h y s i c a l appea rance o f t h e p r e c i p i t a t e . Ammonia was q u a l i t a t i v e l y i d e n - t i f i e d as one o f t h e d e c o m p o s i t i o n p r o d u c t s . The f o r m a t i o n o f ammonia i s p r o b a b l y due t o - a " r e v e r s i o n " r e a c t i o n o f f e r r i c y a n i d e t o f e r r o c y a n i d e :

Hot a c i d i c t r e a t m e n t of t h e complex w i t h

s o l u b l e complex ( i n s o l u t i o n ) and o z o n a t i o n t ime a t a c o n s t a n t

4 Fe(CN)6'3 + 6 OH- + 3 H20 + 02+ 2 Fe(CN)6 - 4 + 2 Fe O'H20 +

2 NH + 2 C 0 2 + 10 C N - ( 4 5 ) 3

A f low scheme f o r a f e r r o c y a n i d e decompos i t ion u n i t i s shown i n F i g u r e 2 4 (page 7 4 ) . The w a s t e f e r r o c y a n i d e and h y d r o c h l o r i c a c i d a r e i n j e c t e d i n t o t h e r e a c t o r v e s s e l where t h e y a re h e a t e d and o z o n a t e d . The o v e r f l o w from t h e r e a c t o r i s t h e n f i l t e r e d t o remove t h e p r e c i p i t a t e t h a t i s formed d u r i n g t h e decompos i t ion . The s o l u t i o n l e a v i n g t h e f i l t e r i s n e u t r a l i z e d w i t h sodium hydrox ide and sewered . The p r e c i p i t a t e from t h e f i l t e r i s c o l - l e c t e d and t r e a t e d w i t h sodium h y d r o x i d e s o l u t i o n t o e x t r a c t t h e complex c y a n i d e s , T h i s s l u r r y i s t h e n f i l t e r e d and t h e f i l t r a t e i s r e c i r c u l a t e d i n t o t h e r e a c t o r . The f i n a l p r o d u c t s a r e sodium c h l o r i d e and i r o n h y d r o z i d e t o t a l i n g a b o u t s i x pounds p e r da?. f o r t h e "average" p r o c e s s i n g inachine.

7 1

5.009 VI

x m

k Q,

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k Q) a 2.007 a a + 0 ,006

*.005 F: .- . \o

v

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z.004

VI

2003 0' r

c,

I+ 0.002

I ! I j !

! I I

+

1

l

0 0 20 9 40 50 60 70 80 90 100 110 120 Time (Min)

Figure 22 Rate of Degradation of Total F e ( C N ) 6 During Acid

Ozone Oxidation Between 70" - 90°C

72

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C o s t / \ i i a l \ * s i s f o r Oionc 1)cconlposit i o n o r Complcx C y n r l i d c s

l - 1 1 ~ c o s t a n a l y s i s f o r . t h c d e s t r u c t i o n ol: €crrocyanidc u s i n g 0:onc i s 3 g a i n bascd on t h c ' ' a v c r a g c ' ' p r o c e s s i n g machinc (pagc 37). Thc runl . r ing t i n e f o r t h e machine was s c t a t c i g l l t h o u r s p c r d a y . ~ q u i p ~ c n t s i z e was b a s e d on a t w c n t y - i o u r h o u r d e s t r u c t i o n c y c l c . The equipllrcnt c o s t es t imate f o r t h i s u n i t i S l i s t e d be low: (25)

4

E q u i pme n t

R e a c t o r vessel; glass-lined steel, SO g a l '

N i x i n g t a n k s ; p o l y e s t e r 50 g a l

P o r t a b l e m i x e r s ; 2 hp r u b b e r c o a t e d s t e e l

H e a t i n g c o i l ; DuPont T e f l o n immers ion c o i l

Pumps; c o r r o s i o n r e s i s t a n t

F i l t e r p r e s s e s ; p l a t e a n d frame

Ozone g e n e r a t i o n u n i t (200 gm/hr)

Labor and m a i n t e n a n c e ( e s t i m a t e d a t 19% cos t !

T o t a l

D a i l y Chemica l Cos t s Q u a n t i t y 1) Oxygen 200 c u b i c f t

C o s t / U n i t

$ 2,000

$ 200

$ 550

$ 1,000

$ 250

$ 1,200

$ 1 4 , 0 0 0

$ 2,480

$25 ,680

c o s t

$ 6 . 6 0

- 2) H y d r o c h l o r i c a c i d 1 l i t e r $ . 7 5

3) Sodium h y d r o x i d e 1 pound $ ,30

D a i l y C o s t of D e s t r u c t i o n : 1 0 y e a r s ) . I n c r e a s e i n , c o s t of p r o c e s s i n g per r o l l of film: Z+/ ro l l .

$171.5'0 ( e q u i p m e n t a m o r t i z e d o v e r

I 7 5 . . .

Removal o f Heavy Complex Cyanides

' I i ' :/Ii I j

!t' P r e c i p i t a t i o n

(Subprogram D)

Copper and z i n c were t h e b e s t m e t a l s t e s t e d w i t h r e g a r d t o comple t eness o f heavy m e t a l f e r r o c y a n i d e p r e c i p i t a t i o n . e v e r , t h e d i f f e r e n c e be tween t h e v a r i o u s m e t a l s t e s t e d was small . T a b l e VI11 (page 7 7 ) shows t h a t t h e b e s t f e r r o c y a n i d e removal r e s u l t e d u s i n g z i n c i o n , ( 9 9 . 8 % ) w h i l e t h e l e a s t e f f e c t i v e was i r o n ( 9 9 . 4 % ) . Copper and z i n c p r e c i p i t a t e s were t h e s l o w e s t t o s e t t l e . A f t e r t h i r t y m i n u t e s , t h e z i n c p r e c i p i t a t e had s e t t l e d t o o n l y 4 0 % o f t h e o r i g i n a l s o l u t i o n h e i g h t , page 7 7 ) . R e s u l t s o f v a r y i n g pH showed a somewhat lower f e r r o c y a n i d e c o n - c e n t r a t i o n when s t a r t i n g w i t h a l k a l i n e s o l u t i o n s . i o n , beyond t h e s t o i c h i o m e t r i c amount f o r comple t e p r e c i p i t a t i o n , l owered t h e f e r r o c y a n i d e c o n c e n t r a t i o n i n t h e s u p e r n a t a n t o n l y

c e n t r a t i o n t o 2 5 % o f t h a t r ema in ing when t h e s t o i c h i o m e t r i c amount of metal was u s e d , A d d i t i o n a l e x c e s s d i d n o t lower t h e concen- t r a t i o n f u r t h e r . (See T a b l e X , page 7 8 ) .

How-

(See T a b l e IX

Excess m e t a l

* w i t h c o p p e r and z i n c . 1 0 % e x c e s s m e t a l r educed t h e complex con-

S e v e r a l t e s t s w e r e r u n w i t h f e r r i c y a n i d e and combina t ions o f i f e r r o - a n d f e r r i c y a n i d e . These e x p e r i m e n t s i n d i c a t e d t h a t f e r r i - c y a n i d e w i l l n o t p r e c i p i t a t e w e l l by i t s e l f . A 9 0 e r c e n t r e -

I d u c t i o n of p u r e f e r r i c y a n i d e was o b t a i n e d u s i n g Fe+q a s t h e p r e - c i p i t a n t , w h i l e t h e o t h e r m e t a l s o n l y removed a b o u t 6 0 % o f t h e Fe(CN) s o l u t i g n , r e d u c t i o n s $ 5 9 9 . 5 9 o r bet: r i n b o t h complex

, Cd+2 and Cu '. (See T a b l e s XI-XIII).

The a n a l y t i c a l p r o c e d u r e f o r f e r r o - a n d f e r r i c y a n i d e i n t h i s s e c t i o n c a l l e d f o r f i l t e r i n g each sample t h r o u g h Whatman 2V f i l t e r p a p e r a s t h e f i r s t s t e p . p a p e r and i t s a b s o r b a n c e measured a g a i n s t t h e same w a t e r which had n o t been f i l t e r e d , t h e v a l u e s a t 2 2 0 mu ranged f r o m 0 . 0 8 t o 0 . 3 5 . T h i s would c o r r e s p o n d t o a f e r r o c y a n i d e c o n c e n t r a t i o n o f f rom 0 . 9 t o 4 . 0 m g / l i t e r . The w a t e r was a p p a r e n t l y l e a c h i n g a m a t e r i a l f r o m t h e p a p e r which c o n t r i b u t e d t o t h e abso rbance a t 2 2 0 mu. I f t h e water was made a c i d , i t had a h i g h e r a b s o r b a n c e a f t e r f i l t r a t i o n t h a n a n e u t r a l s a m p l e , and t y p e s of f i l t e r p a p e r were t r i e d ; a l l w i t h a b o u t t h e same r e s u l t s . The re d i d n o t seem t o b e a u s e f u l c o r r e c t i o n f a c t o r b e c a u s e o f t h e wide d a i l y v a r i a t i o n s . f e r r o c y a n i d e c o n c e n t r a t i o n s may b e h i g h e r t h a n t h e a c t u a l concen- t r a t i o n .

However, w i t h b o t h f e r r o - a n d f e r r i c y a n i d e i n t h e c y a n i d e s

' were o b t a i n e d w i t h Fe

When d i s t i l l e d w a t e r was r u n t h r o u g h t h i s

S e v e r a l d i f f e r e n t b r a n d s

As a r e s u l t , t h e o b s e r v e d

7 6

111,

:0 !d

L - :a1 .on,

In- iount 1-

des

ction er

0 f

e nds

e d en-

TABLE V I 1 1

EFFECT OF XNITlAL pli ON FERROCYANIDE

(Fe (CN) G - ~ ) CONCENTKATION

( m g / l after 30 min settling)

e

(Initial Conc. 750 m g / l Total Complex Cyanide in Each Solution)

TABLE IX

EFFECT OF INITIAL pH ON HEAVY METAL

FERROCYANIDE PRECIPITATION RATE

( % of initial solution height after 30 min settling)

Fe

2 2

29

16

19

Mn

8

4

10

12

L

Cd _I

11

8

10

15 A 4

Cu

34

34

30

28

L Zn

38

46

40

35

-

7 7

TABLE X

EFFECT OF EXCESS HEAVY METAL ON

FERROCYANIDE (Fe (CN) 6-4) SOLUTION CONCENTRATION (mg/l after 30 min settling)

* 1 2 5 * l o o ble tal

* 2 0 0 I on

Fe 6.7 2.9 2 . 8 3 . 1 4 . 1

bin 4 . 2 2 .6 3 . 0 3.0 3 .5

Cd 2 .4 2 . 9 2 .5 3 . 1 2 .7

cu 2 .4 4 .5 1 . 3 1 . 3 1.4

Zn 0 . 7 2 . 3 0.6 0 . 7 0.6

- - *110 - - * 9 0 - -

* PERCENT STOICHIOMETRIC SALT SOLUTION ?Initial Conc. 7 5 0 mg/l Total Complex Cyanide in Each Solution)

bletal I on

TABLE XI

EFFECT OF TEMPERATURE ON HEAVY METAL

FERROCYANIDE (Fe (CN) 6 ) CONCENTRATION

(mg/l after 30 min settling)

-4

- 26°C 46°C - Fe 6.0 4 .0

Mn

Cd

cu

3.6

2 . 3

4.1

3.0

4.0

5 . 0

56°C

4 . 4

1.8

1 .3

4.1

Zn 0.9 3.0 2 . 5

(Initial Conc. 7 5 0 mg/l Total Complex Cyanide in Each Solution)

78

TABLE XI1 A

HLiIVY hIETi\I, 1’RI’CII~~’~ATI~N OF COMPLEX CYANIDES FROM

SOLUTIONS (-(’‘;! \ I ‘ I h l l l \d’rI[ FEKRO-.4ND FERRICYANIDE SALTS

(Initial C O I ~ L . i > O , ~ g / l T o t a l Complex Cyanide in Each Solution)

( m g / l ferrocyanide after 30 min settling)

* s o - * 7 5. - * 9 0 ble tal I on

En 2.9 3.0 2 . 3

* l o o - * 9 5 - - - 2.0 2.6 3 . 3 0

A -

Nn

Cd

- - -

2 . 6

2 . 9

2 . 7 4 . 2

2 .2 2 . 4

7 .0 1 2 . 8

2 .0 2 .2

_ - A l u . z 13.4 U 5 . 2 4.0 3 . 6 CU 4.5

Zn 2 . 3 4 . 2 5 . 9 4 .8 10.2 4.1 0

*PERCENT FERROCYANIDE IN SOLUTION

TABLE XI1 B

HEAVY METAL PRECIPITATION OF COMPLEX CYANIULS PKUM

SOLUTIONS CONTAINING BOTH FERRO-AND FERRICYANIDE SALTS I

I

(Initial Conc. 750 mg/l Total Complex Cyanide in Each Solution)

(mg/l ferricyanide after 30 min s’ettling)

Metal Ion * l o o - * 50 - * 7 5 - * 2 5 *lO -

1.0 1.1 1.0 7 4 1 . 2 0 . 5 Fe

5 3 1 6 1 0 . 2 0 Mn 3 0 0 190 1 8 4

3 . 2 5 . 2 2 .5 0

0 . 8 4.0 3 . 8 0

Cd 3 2 7 2 .8 5 .0

3 0 7 5 .7 7 .0 cu

45 46 2 4 0 2 5 6 4 7 5 5 Zn

*PERCENT FERRICYANIDE IN SO1

79

,UTION

TABLE XI11 A

EFFECT'OF SETTLING TIME ON

FERROCYANIDE CONCENTRATION

"1 Fe (CN) 6 - 4 1

30 Min 5 Min 1 0 Min 20 Min - Me t a l I on

Fe

hln

Cd

cu

Zn

- - - 2.9 3 . 1 3 . 5 3 . 1

6 . 8 6 . 2 6 . 1 5 .9

1 . 9 2.0 2 . 2 2 . 2

3 , 8 5.9

3 . 9 4 . 1

4 . 1 ' 4 .2

4 . 3 4 . 1

'(Initial Conc. 750 mg/l Total Complex Cyanide in Each Solution)

TABLE XI11 B

EFFECT OF SETTLING TIME ON

FERRICYANIDE CONCENTRATION

' 1 Metal 20 Min 30 Min 10 Min

64

2 5 7 272

Ion 5 Min - Fe 7 4 - B i

P 6 4 6 8

2 5 1 2 5 1 Mn

Cd

cu

Zn

330 435 4 1 0 39 7

3 2 0 3 1 5

267 26 7

360 30 2

2 5 2 246

r i i i I

~

I

i

, I

80

b)

F o r t h e p u r p o s e o f compar ison i n t h e c e n t r i f u g a t i o n s t u d i e s , c l a r i t y o f c e n t r i f u g e e f f l u e n t was d e f i n e d a s t h e i n v e r s e o f a b s o r b a n c e . As an example , i f a sample had an a b s o r b a n c e o f 0 . 5 0 , i t s c l a r i t y was 2 . 0 (l/O.S). Any s o l u t i o n w i t h a c l a r i t y g r e a t e r t h a n 3 .0 ( a b s o r b a n c e l e s s t h a n 0 . 3 3 ) a p p e a r e d c l ea r t o t h e u n a i d e d e y e .

I t was e x p e c t e d t h a t i n c r e a s e d r o t o r speed would p roduce g r e a t e r e f f l u e n t c l a r i t y , b u t t h a t was o n l y p a r t i a l l y c o n f i r m e d . As r o t o r s p e e d was i n c r e a s e d , t h e c l a r i t y "peaked" ( i e . , i n c r e a s e d t h e n d e c r e a s e d ) . The S o r v a l l c e n t r i f u g e u s e d i n t h e s t u d y p roduced v e r y l a r g e " g " f o r c e s ; up t o 30,000 t i m e s t h e f o r c e o f g r a v i t y . T h i s c e n t r i p e t a l f o r c e may have b e e n enough t o b r e a k up t h e r a t h e r l o o s e l y bonded a g g r e g a t e p a r t i c l e s , h e l d t o g e t h e r by t h e f l o c c u - l a n t .

4 I t was a l s o a n t i c i p t a t e d t h a t d e c r e a s i n g t h e s l u r r y f low r a t e t h r o u g h t h e c e n t r i f u g e ( i n c r e a s i n g t h e r e s i d e n c e t i m e ) would i n c r e a s e c l a r i t y . Aga in , t h i s was found t o b e o n l y p a r t l y t r u e w i t h t h i s s y s t e m d e s i g n . i n t o t h e c o l l e c t i o n t u b e s and e x p e l l e d w i t h t h e e f f l u e n t . While i n s i d e t h e t u b e s , t h e a i r b u b b l e s d i s t u r b e d t h e s e t t l i n g p a r t i - c l e s and o f f s e t t h e b e n e f i t s o f t h e l o n g e r r e s i d e n c e t ime. C l a r - i t y , t h e n f i r s t i n c r e a s e d a s t h e f l o w r a t e d e c r e a s e d f o r t h i s p a r t i c u l a r s y s t e m .

A d d i t i o n o f N a l c o l y t e 6 7 0 o r P u r i f l o c A-23 p roduced v i s i b l y l a r g e r p r e c i p i t a t e p a r t i c l e s . lier re c l a r i t y was a maximum u n d e r t h e c o n d i t i o n s o f v a r i a b l e f l o w r a t e o r r o t o r s p e e d . T h a t i s , t h e a d d i t i o n of i n c r e a s i n g amounts o f f l o c c u l a n t p roduced c l a r i t y "peak" p o i n t s a t p r o - g r e s s i v e l y lower rpm ' s i n t h e r o t o r s t u d y and a t p r o g r e s s i v e l y h i g h e r f l o w r a t e s i n t h e f l o w s t u d y . The f l o c c u l a n t a l s o iri- c r e a s e d t h e amount of m a t e r i a l removed f rom s o l u t i o n a t t h e s e "peak" p o i n t s . For e ample, F i g u r e 2 5 (page 8 3 ) shows a r o t o r s p e e d s t u d y u s i n g Fe+' i o n . peak i s 5 . 0 a t 8200 rpm f o r t h e r o t o r s t u d y and 50 ml/min f o r t h e f low s t u d y .

P u r i f l o c A-23 p roduced g e n e r a l l y g r e a t e r c l a r i t y t h a n N a l c o l y t e 6 7 0 a t t h e same c o n c e n t r a t i o n . N a l c o l y t e p roduced l a r g e g e l a t i n o u s p a r t i c l e s which c a u s e d c l o g g i n g o f t h e i n l e t p o r t s . The s e d i m e n t b u i l d - u p i n t h e c o l - l e c t i o n t u b e s was q u i t e r a p i d and r e q u i r e d f r e q u e n t c l e a n i n g o f t h e sys t em.

A l l of t h e m e t a l i o n s s t u d i e d p roduced s l u r r i e s t h a t would cen - t r i f u g e w e l l enough, unde r optimum c o n d i t i o n s , t o g i v e e f f l u e n t s c l e a r t o t h e u n a i d e d e y e w i t h o u t t h e u s e o f f i 2 c c u l a n t s Under o p t i m i z e d r o t o r s p e e d and f l o w r a t e , Zn+2, Cd w i t h e i t h e r f l o c c u l a n S p roduced e f f l u e n t s which showed a b s o r b - a n c e s c o r r e s p o n d i n g t o less t h a n 1 m g / l i t e r complex c y a n i d e .

A t low r a t e s , a i r was p r o b a b l y t a k e n

T h i s a d d i t i o n changed t h e p o i n t s

Wi thou t f l o c c u l a n t , t h e c l a r i t y

A t c o n c e n t r a t i o n s of 5 gpm,

and Mn+2 s l u r r i e s ,

i ' i ; i : I

I

8 3

Figures 25 -34 show the results o f the r o t o r s p e e d and slurry f l o w studies on the centrifuge f o r each metal and flocculant investigated.

j !

0 u c CQ P k

‘ 0 lA P < c 0

.I4 c, 3 4 0 v)

k 0

x c,

W

R o t o r Speed (rpm)

F i g u r e 25 E f f e c t o f R o t o r Speed on S o l u t i o n C l a r i t y For I r o n

P r e c i p i t a t i o n of Complex Cyanide Using V a r i o u s F l o c c u l a n t s

a 3

if

Figure 26 Effect of Rotor Speed on Solution Clarity f o r

Manganese Precipitation of Complex Cyanide Using Various Flocculants

a 4

F i g u r e 2 7

P r e c i p i t a t i o n o f Complex Cyanide Using Various F l o c c u l a n t s

E f f e c t o f R o t o r Speed on S o l u t i o n C l a r i t y For Cadmium

8 5

Rotor Speed (rpm)

Figure 28 Effect of R o t o r Speed on Solution Clarity for Copper -

Precipitation of Complex Cyanide Using Various Flocculants

86

A

IO 8 6 4 2 0 10 8 6 4 2 0 10 8 6 4 2 0 IO 8 6 4 2 0 10

6 4 2

a

1 I I I I I I I 1 I 1 I

0 0

LQ

0 0

- a, v. a, N, g 8 " " " O 0 0 0 0 0 0 8 0 0

4 - " m, w, 0, -4-8 a, 7 9 0 1

0 0 0 0

- N e m - ( D o o m - I - - - - ;E Roto r Speed (rpm) J

$

Figure 29 Effect of Roto r Speed on Solution C l a r i t y for Zinc.

Precipitation of Complex Cyanide Using Various Flocculants

8 7

-

F l o w Rat:

F i g u r e 30 E f f e c t o f F low Ra te

P r e c i p i t a t i o n o f Complex Cyanii

on S o l u t i o n C l a r i t y f o r Iron

e Using Various Flocculants

8 8

F l o w Rate (ml/min)

Figure :sl

Precipitation of Complex Cyanides Using Various Flocculants

i . i ! L L t 0 1 - i ' low Rate on Solution Clarity for Manganese

89

Flow Rate (ml/min)

Figure 32


Effect of Flow Rate on Solution Clarity for Cadmium

9 0

6 4 2 0 10 8 6 4

1

I


Figure 33


Effect of Flow Rate on S o l u t i o n Clarity for Copper

91


Figure 34 E f f e c t of F l o w R a t e on S o l u t i o n C l a r i t y f o r Zinc

Precipitation of Complex Cyanides Using V a r i o u s Flocculants

92

I I

J

h

i 0 t

C h l o r i n e D e s t r u c t i o n o f Complex Cyanides

(Subprogram E)

Some d i f f i c u l t y was e n c o u n t e r e d i n c h l o r i n a t i o n s t u d i e s l o n g e r t h a n 20 to 25 h o u r s i n d u r a t i o n due t o s o l u t i o n s a t u r a t i o n o f v a r i o u s s a l t s . These i n c l u d e d sodium c h l o r i d e , p o t a s s i u m c h l o r i d e and sodium h y p o c h l o r i t e . The s a l t s had t o b e removed by f i l - t r a t i o n . I n a d d i t i o n , a s a t i s f a c t o r y u n s o p h i s t i c a t e d method o f pH c o n t r o l f o r l ong t e rm s t u d i e s was n o t f o u n d .

I n g e n e r a l , complex c y a n i d e d e s t r u c t i o n by a l k a l i n e c h l o r i n a t i o n a t room t e m p e r a t u r e was found t o b e v e r y s low ( F i g u r e 35 , page 9 4 ) . On t h e b a s i s o f a one week t e s t , i t would r e q u i r e t h r e e weeks f o r 5 0 0 m l s o f Chlorox t o d e s t r o y t h e f e r r i c y a n i d e i n 5 0 0 ml o f a 20 g / l i t e r p o t a s s i u m f e r r i c y a n i d e {K3Fe(CN) } s o l u t i o n a t 20OC. A t 6 0 ° C t h e same amount c o u l d b e decomposed i$ l e s s t h a n t h r e e

* d a y s , w h i l e a t 9 0 ° C t h e d e c o m p o s i t i o n would o n l y t a k e a b o u t f o u r h o u r s ( F i g u r e 3 6 , page 9 5 ) .

None of t h e c a t a l y s t s (AgNO , NaN03, CdS04, s t e e l wool) a p p e a r e d

ambient t e m p e r a t u r e . The me ta l i o n s (Ag', Cd , Cu ) p r e c i p i t a t e d a s heavy metal s a l t s o f t h e i r o n c y a n i d e complexes . The s t e e l woo l showed no e f f e c t i n n e u t r a l o r b a s i c s o l u t i o n s , however , i n s t r o n g a c i d s o l u t i o n s i t d i s s o l v e d and p r e c i p i t a t e d as f e r r o u s f e r r i c y a n i d e . No f r e e c y a n i d e , hydrogen c y a n i d e o r c y a n a t e were found i n t h e c h l o r i n a t e d s o l u t i o n o r i n t h e decompos i t ion p r o d u c t s . The n l y p r o d u c t s d e f i n i t e l y i d e n t i f i e d were ammonia and f e r r i c ( F e f g ) i o n .

t o i n c r e a s e t h e r a t e o f des 2 r u c t i o n o f t h e c o y p l e x Eyanide a t

A l k a l i n e and a c i d c h l o r i n a t i o n o f f e r r i c y a n i d e a p p a r e n t l y p r o - c e e d by d i f f e r e n t mechanisms. When c h l o r i n e was bubb led i n t o an a l k a l i n e s o l u t i o n , t h e s o l u t i o n d a r k e n e d s l i g h t l y and i r o n h y d r o x i d e , F e ( O H ) 3 , p r e c i p i t a t e d . t h e p r e s e n c e of c y a n a t e and t h e r e a c t i o n p r o c e e d e d t o comple t ion .

I n a c i d m e d i a , t h e s o l u t i o n t u r n e d r e d , t h e n d a r k e n e d t o g r e e n - b l a c k . As t h e r e a c t i o n p r o c e e d e d , a g r a n u l a r , g r e e n - b l a c k p r e - c i p i t a t e formed and c y a n a t e was n o t o b s e r v e d . The maximum a t t a i n a b l e d e c o m p o s i t i o n w i t h a c i d c h l o r i n a t i o n was 8 5 % ; t h e o t h e r 1 5 % o f t h e f e r r i c y a n i d e complex r e m a i n i n g i n t h e p r e c i p - i t a t e . However, i f t h e s o l u t i o n was b a s i f i e d and t h e r e s u l t i n g p r e c i p i t a t e removed, c h l o r i n a t i o n of t h e f i l t r a t e wou ld b e r e - p e a t e d and a n a d d i t i o n a l 8 5 % o f t h e complex removed. T h i s p r o - c e s s o f r e c y c l i n g t h e p r e c i p i t a t e w i t h a c i d c h l o r i n a t i o n t o t h e d e s i r e d f e r r i c y a n i d e l e v e l a p p e a r s t o be t h e most successful '

d e s t r u c t i o n p r o c e d u r e u s i n g c h l o r i n e ;

Q u a l i t a t i v e t e s t s showed

9 3

p

I

C h l o r i n a t i o n D e s t r u c t i o n Cos t A n a l y s i s

D c s i r u c t i o n o f f e r r i c y a n i d e c a n be a c h i e v e d under a c i d i c o r a l k a l i n e c o n d i t i o n s . E i t h e r method would r e a u i r e a p p r o x i m a t e l y t h e saine equipment and each p roduce f e r r i c h y d r o x i d c ^ a s an end' p r o d u c t a t t h e r a t e o f a b o u t f o u r pounds p e r day f o r t h e "com- b i n e d ave rage" p r o c e s s o r , F e r r i c h y d r o x i d e i s n o t a r e a d i l y s a l e a b l e p r o d u c t .

Acid C h l o r i n a t i o n (Figure 3 7 , Page 9 9 )

For a c i d c h l o r i n a t i o n d e s t r u c t i o n of complex c y a n i d e s , t h e b l e a c h o v e r f l o w i s f i r s t c o l l e c t e d and h e a t e d t o a b o u t 90°C. C h l o r i n e gas i s pumped i n t o t h e s o l u t i o n and a l l o w e d t o p roduce an a c i d media , When t h e maximum d e c o m p o s i t i o n has been r e a c h e d ( 8 5 % ) , N a O H i s added t o p r e c i p i t a t e t h e i r o n . The r e s u l t i n g s l u r r y i s pumped t h r o u g h a f i l t e r p r e s s and t h e f i l t r a t e r e t u r n e d f o r f u r t h e r c h l o r i n a t i o n .

The "Cornbined Average" p r o c e s s o r r e q u i r e s 5 . 1 5 kg o f sodium f e r r i c y a n i d e t o p r o c e s s 800 r o l l s o f p h o t o g r a p h i c m a t e r i a l s .

Acid C h l o r i n a t i o n

Equipment

R e a c t o r V e s s e l ; g l a s s - l i n e d s t e e l , 50 g a l

P o r t a b l e M i x e r s , 2 hp r u b b e r c o a t e d s t e e l

H e a t i n g C o i l : DuPont t e f l o n immersion c o i l

Pumps; C o r r o s i o n r e s i s t a n t

F i l t e r P r e s s e s ; p l a t e and frame

Labor and m a i n t e n a n c e ( e s t i m a t e d a t 2 0 % c o s t )

C o s t / U n i t

$ 2.J 0 0 0

$ 5 5 0

$ 1 , 0 0 0

$ 250

$ 1 , 2 0 0

$1,000 w

$ 6 , 0 0 0

Q 6

Chlorine Gas

Daily Chemical Costs

1 7 6 ft3 $8.00

Sodium Hydroxide 20 lbs. $5.50

Hydrochloric Acid 1 liter $0.50

Daily Cost of Destruction: $16.25 [equipment amortized over

Increase in Cost of Processing per roll of film: 2+/roll 10 yearsj

Alkaline Chlorination (Figure 37, page 99 )

Ferricyanide waste bleach overflow would be collected a n d heated to 90°C. During continuous applied chlorination, NaOH is added to maintain alkaline conditions. When the reaction is complete, the solution is pumped through a filter press and the ferric hydroxide removed and dumped, The filtrate is neutralized with HC1 and sewered.

Alkaline Chlorination

Equipment

Reactor Vessel; glass-lined steel, 5 0 gal

Portable Mixers, 2 hp rubber coated steel

Heating Coil: DuPont teflon immersion coil

Pumps; Corrosion resistant

, Filter Presses; plate and frame

Labor and Maintenance (estimated at 20% cost)

Cos t/Uni t

$ 2 , 0 0 0

$ 5 5 0

$1,000

$ 2 5 0

$ 1 , 2 0 0

$1,000

$6,000

9 7

Chlorine Gas

Quantity

710 ft3

c o s t

$ 3 0 . 0 0

Sodium Hydroxide

Hydrochloric Acid

80 l b s

4 liters

$ 2 5 . 0 0

$ 2 . 0 0

D a i l y Cost of Destruction: $59.25 [equipment amortized over

Increase in C o s t of Processing per roll of film: 7.54/roll 10 years]

I

i

Coil

Sewer

Alkaline Chlorination:

Bleach Overflow

NaOH 7Ly HC1

Filter Press c y A v To

t n.- w- . Heating Coil

Figure 37 Chlorination System : Flow Schematics

99

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SECTION V I I

F U L L SCALE O Z O N E BLEACH REGENERATION

A X D WSTE DESTRUC~ION I N S T A L L A T I O W - B E R K E Y PHOTO

O z o n e G e n e r a t i o n and D i s t r i b u t i o n System

The f low d iag ram o f t h e b l e a c h r e g e n e r a t i o n s y s t e m and t h e con- c e n t r a t e d w a s t e o x i d a t i o n s y s t e m i s shown i n F i g u r e 37A (page 1 0 0 ) . The main u n i t s of t h e i n s t a l l a t i o n a r e shown i n Figure 38 (page 1 0 2 ) . The two u n i t s were m a n u f a c t u r e d unde r t h e t r adename OzPAC by Computer ized P o l l u t i o n Abatement C o r p . , L e i c e s t e r , N . Y . The u n i t on t h e r i g h t i s a 1 0 0 gm/hr ozone u n i t , u s e d f o r t h e t r r a t n e n t of w a s t e p h o t o g r a p h i c s o l u t i o n s t o r e d u c e t h e c h l o r i n e demand. The u n i t on t h e l e f t i s a 6 0 gm/hr ozone u n i t , u s e d f o r b l e a c h r e g e n - e r a t i o n and w a s t e t r e a t m e n t .

1 0 0 gm/hour U n i t

T h i s u n i t d i s t r i b u t e s ozone t o t h r e e d i f f e r e n t w a s t e t r e a t m e n t t a n k s by means o f t h r e e f l o w r e g u l a t o r s . These r e g u l a t o r s a r e

‘mounted on t h e f r o n t p a n e l (uppe r l e f t ) o f t h e u n i t . The uppe r r i g h t hand f r o n t p a n e l c o n t a i n s a pH t r a n s m i t t e r and r e c o r d e r . These u n i t s c o n s t a n t l y m o n i t o r t h e pH o f t h e waste e f f l u e n t p r i o r t o s e w e r i n g .

6 0 gm/hour U n i t

T h i s u n i t s e r v e s a d u a l f u n c t i o n , I t s p r i m a r y u s e i s f o r b l e a c h r e g e n e r a t i o n , w i t h s e c o n d a r y u s e f o r w a s t e t r e a t m e n t . When used f o r b l e a c h r e g e n e r a t i o n , t h e ozone i s p i p e d t o t h e t a n k s immedi- a t e l y b e h i n d t h e u n i t . t h e pH t r a n s m i t t e r (mounted on t h e u p p e r r i g h t f r o n t p a n e l ) and i s a u t o m a t i c a l l y m a i n t a i n e d a t t h e d e s i r e d l e v e l by t h e a d d i t i o n o f H B r .

The pH of t h e b l e a c h i s c o n t r o l l e d by

B leach R e g e n e r a t i o n Tanks

F i g u r e 39 (page 1 0 3 ) shows t h e two t a n k s u s e d i n b l e a c h r e g e n - e r a t i o n . The s p e n t b l e a c h flows, by g r a v i t y , i n t o t h e t a n k a t t h e l e f t , f r o m t h e p h o t o g r a p h i c p r o c e s s o r s on t h e f l o o r above. F o r r e g e n e r a t i o n , t h e d e s i r e d amount of s p e n t b l e a c h i s t h e n pumped t o t h e t a n k on t h e r i g h t . A f t e r t e s t i n g f o r t h e concen- t r a t i o n s o f f e r r o - a n d f e r r i c y a n i d e p r e s e n t , t h e p r o p e r amount o f ozone i s f e d i n t o t h e b l e a c h , The r e g e n e r a t e d b l e a c h i s t h e n pumped u p s t a i r s t o a mix ing room, where a small amount o f s o l i d f e r r i c y a n i d e i s added. The b l e a c h i s f i n a l l y pumped t o the re- p l e n i s h m e n t t a n k f o r r e u s e .

1 0 1

i I

I I

i I

i

Figure 38 Ozone Generation And Distribution Systems

Installed at Berkey Film Processing Plant,

F i tchburg , Massachusetts

i02

Figure 39 Ferricyanide Bleach Regeneration Tanks

at Berkey Film Processing P l a n t , Fitchburg,

Massachusetts

103

P h o t o g r a p h i c \Vas t e Trea tmen t Tanks

T h i s sys t em c o n s i s t s o f t h r e e t a n k s on d i f f e r e n t e l e v a t i o n s . A f t e r i n t r o d u c t i o n i n t o t h e h i g h e s t t a n k , t h e was te s o l u t i o n s t o b e t r e a t e d c a s c a d e t o t h e l o w e s t t a n k , f rom which t h e y a r e sewered .

The w a s t e s o l u t i o n s f o r t h i s s y s t e m a r e i n t r o d u c e d from t h r e e d i f f e r e n t p o i n t s , F i r s t , t h e r e i s a c o n t i n u o u s o v e r f l o w from t h e v a r i o u s p h o t o g r a p h i c p r o c e s s o r s . Second, t h e r e i s an i n t e r - m i t a n t f l o w of d e s i l v e r e d w a s t e f i x s o l u t i o n from a s e r i e s o f e l e c t r o l y t i c s i l v e r r e c o v e r y c e l l s . The l a s t s o u r c e i s a s m a l l c o n s t a n t f l o w from a s e r i e s o f f o u r w a s t e h o l d i n g t a n k s , k h i c h p r o v i d e s t o r a g e f o r l a r g e dumps, p r e v e n t i n g s l u g s o f m a t e r i a l f rom p a s s i n g t h r o u g h t h e w a s t e t r e a t m e n t t a n k s t o o r a p i d l y .

The main s o u r c e o f ozone f o r t h i s sys t em i s t h e 1 0 0 gm/hour u n i t . Examples o f t h e ozone d i s t r i b u t i o n a r e : 50 gm/hr i n t h e f i r s t t a n k , 3 0 gm/hr i n t h e s e c o n d t a n k , and 2 0 gm/hr i n t h e l a s t t a n k . When t h e 60 gm/hr u n i t i s n o t b e i n g u s e d t o r e g e n e r a t e b l e a c h , a d i f f e r e n t ozone d i s t r i b u t i o n c a n b e employed, I n t h i s s y s t e m , t h e 6 0 gm/hr i s f e d i n t o t h e f i r s t t a n k and t h e 1 0 0 gm/hr i s d i s t r i b u t e d i n t o t h e l a s t two t a n k s , a t an a p p r o x i m a t e r a t i o n of SO/SO. (FigL:rc -10, ; inge 1 0 5 )

P h o t o g r a p h i c S o l u t i o n T’cs t ing S t a t i o n

F i g u r e 4 1 , (page 1 0 6 ) shows t h e comple t e t e s t i n g s t a t i o n r e - q u i r e d f o r a t y p i c a l p h o t o p r o c e s s i n g p l a n t . T e s t s o l u t i o n s a r e k e p t on a s h e l f , above a g l a s s d r y i n g r a c k . Work a r e a s a r e l o c a t e d on e i t h e r s i d e o f a s i n k . E x t r a c h e m i c a l s and g l a s s w a r e , n e c e s s a r y f o r t e s t i n g , a r e s t o r e d i n t h e c a b i n e t s u n d e r t h e s i n k . T e s t i n g which c a n b e conduc ted a t t h i s t y p e of s t a t i o n a r e : c o n c e n t r a t i o n o f f e r r o - and f e r r i c y a n i d e , pH o f b l e a c h , c h l o r i n e demand o f waste s o l u t i o n , a n d s i l v e r c o n c e n t r a t i o n i n f i x e r s o l u t i o n .

104

Figure 40 Waste Treatment Tanks at Berkey Film

Processing Plant, Fitchburg, Massachusett

105

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SLiC"i'1ON V I i I

AC KNO \JL E 1) G M E NT S

Tiic s u p 7 o i - t sild c o o p e r a t i o n o f h l r . J o e l W e i n s t e i n , B e r k e y F i l m P r o c e s s i n g P l a n t , F i t c h b u r g , M a s s a c h u s e t t s , who made t h i s s t u d y p o s s i b l e , i s a c k n o w l e d g e d w i t h s i n c e r e t h a n k s ,

The b e n c h s c a l e a n d p i l o t p l a n t s t u d i e s , a n a l y t i c a l w o r k , a n d r e p o r t p r e p a r a t i o n were p e r f o r m e d a t C o m p u t e r i z e d P o l l u t i o n A b a t e m e n t C o r p o r a t i o n , L e i c e s t e r , New York .

We a l s o a c k n o w l e d g e t h e s u p p o r t o f t h e p r o j e c t by t h e U.S. E n v i r o n m e n t a l P r o t e c t i o n Agency a n d t h e h e l p a n d g u i d a n c e o f : Fir. W i l l i a m L a c y , Mr. G e o r g e R e y , Flr. A r t h u r H. M a l l o n , a n d Nr. Thomas D e v i n e , t h e P r o j e c t O f f i c e r .

The a d d i t i o n a l s u p p o r t o f Mr. Thomas McMahon, D i r e c t o r , D i v i s i o n of Water P o l l u t i o n C o n t r o l , t h e Commonweal th of M a s s a c h u s e t t s i s a l ' so a c k n o w l e d g e d .

SECTION IX

REFERENCES

1, Sax, N. Irving, Dangerous Properties of Industrial Materials, Rheinhold Publishing Co., New York, 196-3.

2. Burdick, EIB., and Lipschvetz,, M., "Toxicity of Ferro-and Ferricyanide Solutions to Fish, and Determination of the Cause of blortality", Trans. Ami Fish SOC., 78, 192 (1948) CA 4 4 , 10939P.

3. Ono, Sinichi and Tsuchihashi, Genichi, "Oxidation of Ferro- cyanide in Aqueous Solution by Light", Bull. Chem. SOC., Jap. 38(6), p. 1052-3, 1965, (Eng.) CA 63, 6 530.

4. Emschwiller, Guy and Legros, Jacqueline, "Photochemical Hydrolysis of Ferrocyanide", Compr. Rend. 261(6), (Group7) , p. 1535-8 (1965) (Fr.) CA 63 17632e.

Photoxidation of Aqueous Fe +2'Species", Nature, 207 (5002) p. 1190-1, (1965), CA 63, 15761a.

5. Dainton, F.S. and Airey, P.L "Primary Processes of

6. Kongiel-Chablo, Irena, "Behavior of Complex Cyanides in Natural Water with High Rate of Contamination", Roczniki Panstwaowego Zakladu Hig., 17(1), p. 95-102, 1966.

in Water Ponds", Hydrochemical Materials, Vol. 37, p. 133-43, Moscow, Russia, 1964.

Biological Systems", Report EHL (K) 70-9, USAF Environmental Health Lab, Kelly Air Force Base, Aug. 1970.

Picture Film Processing" J . SMPTE, - 79, p . 765-771 ( 1 9 7 0 ) .

Hendrickson, Thomas N.,"Pollution and the Television Film Processing Laboratory". Meeting of the National Association of Broadcasters, Chicago, Illinois, April (1972).

7. Lur'e, Yu.Yu. and Panova, V.A., "Behavior of Cyano Compounds

8. "Toxic Effects of Color Photographic processing Waste on

9. West, Lloyd E , , "Disposal o f Waste Effluent from Motion-

10. Paper to be presented at the National

11. Condensed Chemical Dictionary, 5th Edition, 1956.

12. Alletag, Gerald C., "Truth in Pollution Ahatement" Paper presented at Pure Meeting, Washington, D.C., April 6, 1971..

Glasstone, S . , Textbook of Physical Chemistry, D. Van Nostrand Co., New York, 1951.

13.

1 4 , Dobcz' , T., and Dagon, T . , "Rcgcncration of Ferrocyanide B l e n c h Using Ozone", paper presented at Society of Photo- qraphic Scientists and Engineers Convention, Chicago, Illinois, April 22 , 1971.

1 5 .

16.

17.

18.

19.

io

21.

22.

23.

24 .

25.

26.

27 .

2 8 .

29 .

Levenspiel, O., Chemical Reaction Engineering, John Wiley 4 Sons inc., New York, 1964.

American Cyanamid, The 'Chemistry. of Ferrocyanides, Beacon Press, New York, 1 9 3 3 .

Selm, R.P., "Ozone Oxidation of Aqueous Cyanide Waste Solution in Stirred Batch Reactors and Packed Towers", Advances in Chemistry Series, 21, American Chemical Society, Washington, D.C. 1959.

Laubusch, E. J., "Chlorination of Wastewater", Water and Sewage Norks, v o l . 1 0 5 , 1 9 5 8 .

Moore, W., Physical Chemistry, Prentice-Hall, Englewood Cliffs, New Jersey, 1962.

U.S. Patent 2 , 9 8 1 , 6 8 2 : Chlorination of Water Soluble Iron Cyanide Compounds Using Mercuric Chloride Catalyst.

U . S . Patent 3,101,320: Conditioning Cyanide Compounds.

Kodak Professional Handbook, Motion Picture and Education harkets Division, Eastman Kodak C o . , Rochester, New York, 1967, Procedure 1 1 0 2 - A .

Ibid., procedure llOOF

Ibid., procedure l l O l B

Ibid., procedure 1122

Dryden, C. and Furlow, R., Chemical Engineering Costs, Engineering Experiment Station, Ohio State University, Columbus, Ohio, 1966.

G . J . Alohanrao, K.P. Xeishnamoorthis and 1V.M. Deshande, "Photo-Film Industry Waste: Pollution Effects and Abate- ment", Third International Conference on Water Pollution Research, Section 1, No. 9 , Water Pollution Control Feder- ation, 1 9 6 6 .

C.J. Terhaar, Ewell, W.S., Dziuba, B.S., and Fassett, D.W.,. "Toxicity of Photographic Processing Chemicals to Fish" presented to SPSE Meeting, Chicago, April 22, 1971.

Sollinann, Torald; "Correlation of the Aquarium Goldfish Toxicities o f Some Phenols, Quinones, and other Benzene Derivatives with their Inhibition of Autooxidative Reactions.

110

3 0 .

31.

3 2 .

3 3 ,

34.

3 5 .

36.

3 7 .

3 8 .

3 9 .

40.

41.

42.

4 3 .

44.

45.

?', 11 . Y . T e b b u t t , "Prob lcins of T o x i c E f f l u e n t s " E f f i u c n t a n 3 i t n t c r Trca tmcn t Journal, 6:316-17, 3 1 9 - 2 1 , J u l y , 1 9 6 6 .

G1-cciiwc11, T . X . and B I - C W C ~ , P.E. ; " O p e r a t i o n o f a Two-Staged A e r a t i o n L a g o o n bn P h o t o g r a p h i c Vas t c E f f l u e n t " . a t SPSE c o n f e r e n c e , A p r i l 2 2 , 1 9 7 1 .

P r e s e n t e d

D i s p o s a l o f P h o t o g r a p h i c Was te s , Kodak P u b l i c a t i o n No. 5 - 2 8 , Eastman Kodak C o . , R o c h e s t e r , N e w Y o r k , 14650.

Bobel l , T , W , , "Pollution AbRt@li le l l t i M i n t You Can Do i n t h e Caineraroom" Kodak B u l l e t i n f o r t h e G r a p h i c Arts No, Eastman Kodak Company, 1 9 7 0 .

2 1 ,

H e n d r i c k s o n , T . N . D u r b i n , H . E . , " P h o t o g r a p h i c N a s t e s a s P o l l u t a n t s " C r e d i t L i n e C - P A C , J a n u a r y 1 9 7 1 .

LeFebvre , E . E . and C a l l a h a n , R.A.;"The T o x i c E f f e c t s o f C o l o r P h o t o g r a p h i c P r o c e s s i n g Wastes on B i o l o g i c a l Systems' ' p r e s e n t e d a t SPSE, A p r i l 2 2 , 1971.

Zehnpfenn ig , R . G . , " P o s s i b l e T o x i c E f f e c t s o f C y a n a t e s , T h i o c y a n a t e s , F e r r i c y a n i d e s , F e r r o c y a n i d e s and Chromates on S t r eams" ,

H e n d r i c k s o n , T .N . ; " P o l l u t i o n Problems t h e P h o t o f i n i s h e r Must Face", Photo M a r k e t i n g , J u n e , 1 9 7 0 .

"The P r e p a r a t i o n o r R e g e n e r a t i o n o f a S i l v e r B leach S o l u t i o n b y O x i d i z i n g F e r r o c y a n i d e w i t h P e r s u l f a t e " B . A . H u t c h i n s and L.E. West, J . SMPTE, 6 6 , pp . 764-768, Dec., 1 9 5 7 .

"Method f o r O x i d i z i n g P o t a s s i u m F e r r o c y a n i d e t o Po ta s s ium F e r r i c y a n i d e , " U.S. P a t e n t 1 , 7 3 2 , 1 1 7 , Oct. 1 5 , 1 9 2 9 .

" E l e c t r o l y t i c P r e p a r a t i o n o f A l k a l i Metal F e r r i c y a n i d e , ' ' U.S. P a t e n t 2 ,353 ,781 , J u l y 1 8 , 1944.

" E l e c t r o l y t i c P r e p a r a t i o n o f Sodium F e r r i c y a n i d e , " U.S. P a t e n t 2 ,353 ,782 , J u l y 1 8 , 1 9 4 4 .

"Recove r ing S i l v e r . f rom F i x Ba ths , I 1 Eastman Kodak C o . , Pamphle t #J-lO.

" S i l v e r Recovery f rom Exhaus ted F i x i n g Bath" J . I . C r a b t r e e and J . F . R o s s , T r a n s . o f SMPE , No, 26.

"Automat ic S i l v e r Recovery" K . Hickman, J . o f SMPE, V o l . X V I I , N O . 4 , pp. 591-603, 1931.

" N o n i n s t r u n e n t a l D e t e r m i n a t i o n o f S i l v e r i n F i x i n g Ba ths , " B . A . H u t c h i n s , J . SMPTE, Vol , 7 5 , No. 1, p p . 1 2 - 1 4 , J a n . , 1966 .

111

4 6 .

4 7 .

4 8 .

49.

5 0 .

- . > - .

5 2 .

3 3

!'A S i l v c r Recovery A p p a r a t u s f o r O p e r a t i o n a t High C u r r e n t D e n s i t i e s , " N.J. Cedrone , J . SMPTE, Vol. 67 , Mar. 1958.

"The E l c c t r o l y t i c R e g e n e r a t i o n of F i x i n g Ba ths , I 1 K. Hickman , C . S a n f o r d , 1J. W e y e r t s , Communications H471, Kodak R e s e a r c h L a b o r a t o r i e s .

"Tile A r g e n t o m e t e r - An A p p a r a t u s f o r T e s t i n g f o r a F i x i n g Bath" , N.J. Weyer t s and K . C . D . Hickman, Cc.:Lailnication r f 5 4 S J Kodak R e s e a r c h L a b o r a t o r i e s , 1935.

v e r i n

- - "The Recovery o f S i l v e r f rom E x h a u s t e d F i x i n g Ba ths" , 3 .

C r a b t r e e and J . F . R o s s , C m m u n i c a t i o n # 2 8 0 , Kodak R e s e a r c h L a b o r a t o r i e s .

I .

" E l e c t r o l y s i s o f S i l v e r B e a r i n g T h i o s u l f a t e S o l u t i o n s ' ' K . i-iickman, 'd. lv'eyerts , O . E . G o e h l e r , I n d u s t r i a l and E n g i n e e r i n g Zhe in i s r ry , V o l . 25 , p . 202, Feb, 1933 .

" E l e c t r o l y s i s o f Complex S i l v e r S a l t S o l u t i o n s " D r . T i b o r Erdey-Gruz and D r . V a r e r i a H o r v a t h y , Magyar Kim-Lap,@, 4, p p . 5 2 4 - 5 3 1 , 1949 , i3udapest U n i v e r s i t y o f S c i e n c e .

" E l e c t r o l y t i c Recovery o f S i l v e r f rom F ix i i l g B a t h s a t La.. . < u r r e n t D e n s i t y " A . A . Rasch and J . I . C r a b t r e e , ?hotogr;p:.s .

S c i e n c e and T e c h n i q u e , S e r i e s I I , V o l . 2 , No. 1, pp 1 " e p . 195- b .

3;

' E l e c t r o l y t i c Recovery of S i l v e r f rom Used F i x e r Bath" H . X i s e n b r e y and U. F r i t z e , R o n t g e n p r a x i s , V o l . 1 9 , 3 0 . 11, p p . 2 8 4 - 3 0 2 , 1966 .

54. "The Problem o f S i l v e r Recovery f r o m E x h a u s t e d Fixi .*g S o l u t i o n s ' ' G . A . Namias, P r o g r e s s 0 F o t o g r a f i c o , 44, No. 7 , p p . 2 7 2 - 2 7 4 , J u l y 1939.

5 5 . " E l e c t r o d e s p o s i t i o n o f S i l v e r w i t h Superimposed A l t e r n a t l n g C u r r e n t " Lar i ssa Domnikov, Me ta l F i n i s h i n g , G3, p p . 6 2 - 6 6 , 1965 .

5 6 . " E l e c t r o l y t i c S i l v e r Recovery - A Survey ' ' D . C . B r i t t o n , B r i t i s h Kinematography, V o l . 45 , No. 1, J u l y 1 9 6 4 .

5 7 . " E l e c t r o l y t i c Recovery o f S i l v e r " M . C . K i n s l e r , ?hotograpI;-; P r o c e s s i n g , V o l . 3 , No. 6 , J u n e / J u l y , 1968.

I

58. "Recovery o f S i l v e r f rom Wash Wate r s by i o n i c Exchange Chromotography" A . B . Dcvankov, V.M. i a u f e . , A . A . >f i ronon , T.S. S i s h u n o v a , Zhurna l Nauchnoi , P r i k l a d n o i F o t o g r a f i i K i n e m o t a g r a f f i , 1 3 , p p . 1 4 - 1 9 , 1968 .

I

5 9 . " A S i l v e r - R e c o v e r y A p p a r a t u s f o r O p e r a t i o n a t High C u r r e n t D e n s i t i e s " N . J. Cedrone , SMPTE, V o l . 6 7 , No. 3 , pp . 1 7 2 - 1 7 4 , March 1 9 5 8 .

112

60.

6 1 .

62 .

6 3 .

64.

6 5 .

6'6 . 67.

6 8 ,

69 .

70.

7 i .

7 2 .

7 3 .

74.

7 5 .

76.

77.

78.

. A , ' 'Tiie Recovery o f S i l v e r f rom Exhaus tcd F i x i n g B a t h s " J C 1 - ~ i b t 1 ' e e and J . F . R o s s , ,4merican Annual o f Photography!- 1927.

"The R e c o v e r y o f S i l v e r f rom F i x i n g Baths b y t h e E l e c t r o l y t i c blcthod" C e s a r e d e b l i t r i , F e r r a n i a A - Magaz ine , V o l . XI1 , No, 1, 1964.

' :Ext rac t ion of C o l l o i d a l S i l v e r S u l f i d e f rom i t s Hydroso l b y E m u l s i f i c a t i o n " L . D . S k r y l e v , V . I . B o r i s i k h i n a , S .G. J l l k r u s h i n , Z h u r n a l . P r i k l a . d n o i K h i m i i , V o l . 37 , No . 3 , pp 693- 6 9 5 , Narch 1964.

T

U.S. P a t e n t 1 , 8 6 6 , 7 0 1 : Method and A p p a r a t u s f o r Recove r ing S i l v e r froin F i x i n g S o l u t i o n s .

U .S . P a t e n t 476 ,985: P r o c e s s and A p p a r a t u s f o r t h e E l e c t r o l y s i s o f P h o t o g r a p h i c F i x i n g S o l u t i o n s .

U.S. P a t e n t 2 , 4 9 3 , 3 9 6 : Recovery o f S i l v e r f rom S o l u t i o n s o f S i l v e r S a l t s .

U.S. P a t e n t 2 , 5 0 3 , 1 0 4 : P r o c e s s f o r P r e c i p i t a t i n g S i l v e r f rom S o l u t i o n .

U.S. P a t e n t 2 , 5 0 7 , 1 7 5 : S i l v e r Recovery .

U.S. P a t e n t 2 , 5 2 9 , 2 3 7 : E1 ,ec t ro -Recovery o f M e t a l s .

U.S. P a t e n t 2 , 5 4 5 , 2 3 9 : Recovery o f Gold o r S i l v e r .

U.S. P a t e n t 2 , 5 7 9 , 5 3 1 : P r o c e s s f o r E x t r a c t i n g Gold'or S i l v e r

U.S. P a t e n t 2 ,607 ,721 : S i l v e r Recovery f r o m Sodium T h i o - s u l f a t e S o l u t i o n s .

U.S. P a t e n t 2 , 6 1 2 , 4 7 0 : S e l e c t i v e E l e c t r o d e p o s i t i o n o f S i l v e r .

U.S. P a t e n t 2 , 6 1 9 , 4 5 6 : M e t a l Recovery A p p a r a t u s .

U.S. P a t e n t 2 , 7 9 1 , 5 5 6 : A p p a r a t u s f o r the Recovery o f S i l v e r f rom P h o t o g r a p h i c P r o c e s s i n g B a t h s .

U.S. P a t e n t 2 , 9 0 5 , 3 2 3 : A p p a r a t u s f o r t h e Recovery o f S i l v e r f rom S p e n t P h o t o g r a p h i c S o l u t i o n s .

U.S. P a t e n t 2 ,934 ,429 : S i l v e r Recovery P r o c e s s .

U . S . P a t e n t 3 , 0 0 3 , 9 4 2 : E l e c t r o l y t i c C e l l For Recovery o f S i l v e r from S p e n t P h o t o g r a p h i c F i x i n g B a t h s .

U.S. P a t e n t 3 ,082 ,079 : S i l v e r Recovery f r o m P h o t o g r a p h i c F i x i n g S o l u t i o n s ,

113

79. U . S . P n t c n t 3 , 9 4 3 , 4 3 2 : A p p a r a t u s for Recovery o f S i l v e r f roin S p e n t P h o t o g r a p h i c S o l u t i o n s .

8 0 . U.S. P a t e n t 3 , 3 1 1 , 4 0 8 : S i l v e r Recovery P r o c e s s .

81. S c h r e i b e r , bl. L . , “ P ; e s e n t S t a t u s of S i l v e r Recovery i n t h e b l o t i o n P i . c t u r e I n d u s t r y , : J . SMPTE, V o l . 7 4 , J u n e 1 9 6 5 .

1 1 4

SECTIOS ;i

GLOSSARY

Absorbance - The n e g a t i v e loglo o f t h e p e r c e n t t r a n s m i s s i o n o f r a d i a n t e n e r g y .

Aerob ic - R e q u i r i n g , o r n o t d e s t r o y e d by , t h e p r e s e n c e of f r e e e l e m e n t a l oxygen.

Anode - The p o s i t i v e e l e c t r o d e o f a n e l e c t r o l y t i c c e l l where o x i d a t i o n o c c u r s , - - BOD - A b b r e v i a t i o n f o r b i o c h e m i c a l oxygen demand, oxygen used i n t h e b i o c h e m i c a l o x i d a t i o n of o r g a n i c m a t t e r i n a s p e c i f i e d t i m e , a t a s p e c i f i e d t e m p e r a t u r e , and under s p e c i f i e d c o n d i t i o n s .

The q u a n t i t y o f

Cathode - The n e g a t i v e e l e c t r o d e of an e l e c t r o l y t i c c e l l where ‘ r e d u c t i o n o c c u r s .

C h l o r i n a t i o n - The a p p l i c a t i o n of c h l o r i n e t o w a t e r o r w a s t e w a t e r , g e n e r a l l y f o r t h e p u r p o s e of d i s i n f e c t i o n , b u t f r e q u e n t l y f o r a c c o m p l i s h i n g o t h e r b i o l o g i c a l o r chemica l r e s u l t s .

C h l o r o x - - R e g i s t e r e d t r a d e mark, Chlorox Corp . , Oakland , C a l i f o r n i a ; c o n t a i n s 5 % sodium h y p o c h l o r i t e by w e i g h t .

C l a r i t y - The i n v e r s e o f a b s o r b a n c e .

- C O D - A b b r e v i a t i o n f o r c h e m i c a l oxygen demand. A measure o f t h e oxygen - consuming c a p a c i t y o f i n o r g a n i c and o r g a n i c m a t t e r ? r e s e n t i n w a t e r o r w a s t e w a t e r . It i s e x p r e s s e d a s t h e amount o f oxygen consumed from a chemica l o x i d a n t i n a s p e c i f i c t e s t . I t does n o t d i f f e r e n t i a t e between s t a b l e and u n s t a b l e o r g a n i c m a t t e r and t h u s does n o t n e c e s s a r i l y c o r r e l a t e w i t h b i o c h e m i c a l oxygen demand. A l s o known a s OC and D O C , oxygen consumed and d i c h r o m a t e oxygen consumed, r e s p e c t i v e l y .

Complex Cyanide - F e r r o c y a n i d e { F e (CN) 6-4) a n d / o r f e r r i c y a n i d e XFe ( C N ) 6 - 3 ) .

C o n c e n t r a t i o n P o l a r i z a t i o n - The p r o d u c t i o n of any i r r e v e r s i b l e p o t e n t i a l a t t h e s u r f a c e o f an e l e c t r o d e by change of i o n i c co’n- c e n t r a t i o n i n t h e immedia te v i c i n i t y of t h e e l e c t r o d e .

Conver s ion - The o x i d a t i o n of f e r r o c y a n i d e t o f e r r i c y a n i d e .

I Coulomb - The c u r r e n t p a s s e d when 1 amp f l o w s f o r 1 s e c o n d .

C u r r c n t c l c x i - + \ * ~ . i i i - i - ~ \ n t p e r u n i t a r e a o f e l e c t r o d e s u r f a c e .

1 1 5

I

Current density ratio - The ratio o f current-density of the cathode to the current density of the anode.

Cuvette - A cell used for spectrophotometric measurement.

Electrolysis - Affecting a chemical change by means o f an applied electric current.

Equivalent weight - The amount of a substance which reacts with one Faraday; usually the formula weight divided by the valence.

Farad3 - An amount o f electricity equal to 96,487 coulombs --Z-c) . Flocculation - In water and wastewater treatment, the agglomeration of colloidal and finely divided suspended matter after coagulation by gentle stirring by either mechanical or hydraulic means.

F-low Study - A centrifugation study in which the rotor speed remains constant while the f l o w rate is varied.

I o n permeable membrane - A membrane which allows only select ions to pass through.

K - 1 2 F Bleach - Ferricyanide bleach used in processing Kodachrome reversal f i l m .

Kodachrome - Trade name for color film manufactured by the Eastman Kodak C o .

Oxidation - The process by which atoms of an element lose electrons. Ozonation - Affecting a chemical change by means of ozone.

Photochemical - Achemical reaction catalyzed by light. Prussian Blue - Ferric ferrocyanide. Reduction - The process by which atoms of an element gain electrons.

Regeneration - The oxidation of ferrocyanide to ferricyanide.

Stoichiometric - Pertaining to or involving substances which are in the exact proportions required for a given reaction.

Supernatant - The liquid standing above a sediment or precipitate.

-Synergism - The improvement in performance achieved because two agents are working together.

116

.

a

l ! ; c o i . c t i c c i l O i y s c n ilcmond (TOP) - T h e t h c o r e t i c a l amount o f o ~ y g c i i t W L o u l i i b c consumed i f a c h e m i c a l were to be oxidized t o t h e highest oxidation state of each element in the compound. (i.e. CO2, HzO, etc.)

Toxicity - The quality of being poisons.

Abbreviations Used

g - grams

1 - liters

Nin - minutes

-

- 3 - milligrams

nl - milliliters

- - millimicrons (10-9 meters) = nm (nanometers)

-

ppm - parts per million - mg/l (milligrams per liter)

117

S E C T I O N XI

APPENDICES

Page No.

A Reagents Used in Various Ferro-Ferricyanide Analysis Procedures

hlethod of Analysis of Ferrocyanide in the Presence of Ferricyanide

C Centrifugation Procedure

D Detailed Analytical-Procedures

E

B

The Photographic Process and Sources o f Pollution

1 2 0

1 2 1

122

123

1 2 7

134

135

Figure E-1

Table E-1 Steps in Color Process

Table E - 2 Ions or Compounds Found in Black-and-

Ektachrome Reversal Film Process

136 White and Color Processing Solutions

Table E-3 Approximate Chemical Concentrations in Effluents from Photo Processing

139 Machines

Table E-4 BOD of Chemicals Used in Photographic 141

Table E - 5 Relative Ineffectiveness of Biological

Processing

Type of Treatment of Photographic Chemicals 142

143 F Waste Treatment Facilities Presently in Use

Table F - 1 Concentration of Chemicals in Waste Effluent at Typical Photo- finishing Plants 149

150 Table F - 2 Chemicals Removed by Treatment

119

APPENDIX A

Reagents Used in Various Fcrro - Ferricyanide Analysis Procedures

Reagents Used Procedures in Which Reagents Are Used

1) 0.6 EIolar Potassium Iodide (49.8 gm K I / 5 0 0 ml)

2 ) Zinc Sulfate-Sulfuric acid reagent (125 gm ZnSO 7H 0, dissolved in 7.0 N H 2 S O 4 &luge to s o 0 ml)

t-'

0 N 3 ) 0.100 Normal Sodium thiosulfate

(24.82 gm Na2S203' 5H20/liter

4 ) Starch Solution: 1.0 gm starch (in 10 cc cold H 0, stir into 2 0 0 cc boiling water) 2

5) 2.5 Normal Sodium Hydroxide (110 g"

6 ) Ferrous - Ferric reagent ( . 7 5 gm FeC12) 20 ml H 0 (distilled) ( . 7 5 gm FeC13) 3.0 ml 6 CL - dilute to 30 ml

7) 7.0 Normal Sulfuric Acid

8) 0 . 0 5 0 Ceric sulfate (26.4 gm/l)

1) Cerimetric determination-of ferricyanide

2 ) Cerimetric determination of ferricyanide

3) Cerimetric determination of ferricyanide

4 ) Cerimetric determination of ferricyanide

5) Spec t roplio t ome t r ic de t e rmina t ion f e r ro - cyanide

6) Spectrophotometric determination of ferrocyanide (modified Kodak method)

7) Cerimetric and potentiometric determination

8) Cerimetric determination of ferrocyanide ferrocyanide

* Lr +

APPENDIX B

Method o f A n a l y s i s o f F e r r o c y a n i d e

i n t h e P r e s e n c e o f F e r r i c y a n i d e

1) C o n c e n t r a t i o n o f f e r r i c y a n i d e m e a s u r e d 4 ) C i l c u l a t e c o n t r i b u t i o n t o t o t a l 2’0 r r u s i n g a b s o r b a n c e a t 417 mu. (Column 1 a n d 2 ) al , r , r b a n c e due t o f e r r o c y a n i d e .

( c ~ ~ l t i i r i n 3 minus co lumn 4 l i s t e d in 2) S i n c e b o t h f e r r o - a n d f e r r i c y a n i d e a b s o r b co L t i y i n 5)

a t 2 2 0 mp, a b s o r b a n c e a t 2 2 0 m p i n c l u d e s c o n t r i b u t i o n f r o m b o t h . (co lumn 3) 5) C l :( i l<ite c o n c e n t r a t i o n o f fe r roc ,yn:* i i ld

i i - : r i p a b s o r b a n c e a t 2 2 0 m p 3 s shc>,.i? i n 3) C a l c u l a t e c o n t r i b u t i o n t o t o t a l 220 m p c ~ l u r n r i 5 ( co lumn 6 )

a b s o r b a n c e due t o f e r r i c y a n i d e (coulmn 4 ) ( 1 0 0 g m / l f e r r i c y a n i d e h a s a n a b s o r b a n c e of 1 . 5 2 a t 2 2 0 mu )

Below i s a s a m p l e r u n u s i n g known c o n c e n t r a t i o n s o f f e r r o and f e r r i c y a n i d e . 1 2 3 4 5 6 7

Total C a l c u l a t e d T o t a l A b s o r b a n c e Ab s o r b anc e C a l c u l a t e d A c t u a l c o n c e n - A b s o r b a n c e C o n c e n t r a t i o n A b s o r b a n c e d u e t o due t o C o n c e n t r a t i o n t r a t i o n m g / l

a t 417 m p F e r r i c y a n i d e a t 2 2 0 mp F e r r i c y a n i d e F e r r o c y a n i d e F e r r o c y a n i d e f e r r i f c r r o - ~ _ _ _ ._

a t 2 2 0 mp a t 2 2 0 mi l a t 2 2 0 mp ___- mg/ 1

1 . 4 0 316 2 9 . 5 5.00 2 4 . 5 236 3 2 0 2 5 6

. 3 7 8 3 8 . 1 1 . 2 0 6 . 9 0 6 5 8 0 6 4

.09 5 20 1 . 9 5 .36 1 . 5 9 1 5 2 0 1 6

. 0 4 8 1 0 1 . 0 0 . 1 7 - 8 3 8 1 0 8

.72 162 1 5 . 1 2 . 4 5 1 2 . 5 5 1 2 1 1 6 0 12s

. 1 a6 4 1 4 . 0 . -60 3 . 4 0 33 4 0 32

APPENDIX C

C e n t r i f u g a t i o n P r o c e d u r e

A. S t a r t c e n t r i f u g e and slowly i n c r e a s e r o t o r s p e e d t o 6 5 0 0

B. F i l l c o l l e c t i o n t u b e s f rom c a r b o y a t 25 ml/min. When t u b e s

rpm. ( N a n u f a c t u r e r ' s recommended minimum s p e e d )

a r e f i l l e d , s t o p f l o w and a l l o w c e n t r i f u g e t o r u n f o r f i v e m i n u t e s t o s t a b i l i z e t u b e c o n t e n t s ,

C . R o t o r S t u d y ( C o n s t a n t Flow)

1) On t h e i n i t i a l r u n f o r e a c h m e t a l , a c o n s t a n t f l o w o f 2 5 ml/min was u s e d ; on s u b s e q u e n t r u n s , t h e optimum f l o w from t h e p r e v i o u s r u n was u s e d .

2 ) S t a r t f l o w and a l l o w t o r u n f o r two m i n u t e s a t 6 5 0 0 rpm, t a k e a 1 0 m l s ample and s h u t o f f f l o w .

Slowly i n c r e a s e r o t o r s p e e d t o n e x t s t e p and a l l o w two m i n u t e s f o r s t a b i l i z a t i o n .

3)

4)

5) When maximum s p e e d h a s b e e n r e a c h e d , f o l l o w same p r o c e d u r e

S t a r t f l o w and a l l o w t o r u n f o r two m i n u t e s b e f o r e t a k i n g sample . S h u t o f f f l o w and i n c r e a s e r o t o r s p e e d .

d e c r e a s i n g r o t o r s p e e d s t e p w i s e .

D. Flow S tudy ( C o n s t a n t R o t o r Speed)

1) Flow s t u d y f o r e a c h meta l c a r r i e d o u t a t t h e optimum r o t o r s p e e d f o r t h e p a r t i c u l a r me ta l and f l o c c u l a n t c o n c e n t r a t i o n .

2 ) A f t e r r o t o r s p e e d h a s b e e n o b t a i n e d , a l l o w f i v e m i n u t e s f o r s t a b i 1 i za t i o n .

3) S t a r t f l ow a t 6 ml/min and a l l o w t o r u n f o r f o u r m i n u t e s (two minu tes i n a l l o t h e r c a s e s ) and t a k e a 1 0 m l s ample S h u t o f f f l o w f o r 2 m i n u t e s .

4)

5 ) When-maximum f l o w r a t e h a s been r e a c h e d , f o l l o w same

S t a r t f l ow a t n e x t h i g h e r r a t e and r u n f o r two m i n u t e s b e f o r e t a k i n g s a m p l e .

p r o c e d u r e , d e c r e a s i n g f l o w r a t e s t e p w i s e .

1 2 2

A P P E N D I X D

D e t a i l e d , A n a l y t i c a l P r o c e d u r e s

P o t e n t i o i i i c t r i c d e t e r m i n a t i o n of f e r r o c y a n i d e i n p r o c e s s K - 1 2 F b l e a c h ( 2 2 )

Add 2 5 0 m l o f d i s t i l l e d w a t e r t o a 4 0 0 m l b e a k e r and p l a c e on a magne t i c s t i r r e r a t s l o w speed u s i n g a magnetic stirring b a r ,

P i p e t ( h e l d v e r t i c a l l y ) 5 . 0 m l of sample i n t o t h e b e a k e r .

Add 1 0 d r o p s 0.010 N Sodium D i p h e n y l a m i n e s u l f o n a t e i n d i c a t o r .

P l a c e e l e c t r o d e s f rom a p H - m i l l i v o l t m e t e r i n t o s o l u t i o n .

T i t r a t e s o l u t i o n , f rom a 50 m l b u r e t t e , w i t h 0 , 0 5 0 N Ceric s u l f a t e i n 0 . 5 m l a l i q u o t s , r e c o r d i n g b o t h b u r e t t e and m t e r r e a d i n g s .

F i n d e n d p o i n t by d e l t a method

C a l c u l a t i o n : 4.84 x (ml) o f 0 . 0 5 0 c e r i c s u l f a t e added a t e n d p o i n t ) = g r a m s / l i t e r of Na4Fe(CN)6'10 H20 i n s ample .

I o d o m e t r i c d e t e r m i n a t i o n o f f e r r i c y a n i d e i n p r o c e s s K - 1 2 F B leach (23)

P i p e t 5 . 0 ml of sample and 5 m l o f d i s t i l l e d w a t e r i n t o a 2 5 0 in1 Er lenmeyer f l a s k , and p l a c e on a m a g n e t i c s t i r r e r a t slow s p e e d .

P i p e t 25 ml of 0 .6 M p o t a s s i u m i o d i d e s o l u t i o n and 2 0 m l o f z i n c s u l f a t e - s u l f u r i c a c i d r e a g e n t . (See Appendix A)

T i t r a t e w i t h 0.100 N sodium t h i o s u l f a t e u n t i l c o l o r changes t o p a l e y e l l o w .

P i p e t 5 m l o f s t a n d a r d s t a r c h s o l u t i o n i n t o t h e f l a s k .

Con t inue t i t r a t i o n u n t i l t h e b l u e c o l o r d i s a p p e a r s .

C a l c u l a t i o n : 5 .6 x (ml o f 0 . 1 0 0 N Na S 0 added a t e n d p o i n t ) - g r a m s / l i t e r Na3 Fe(CN),'iA Jample .

I o d o m e t r i c D e t e r m i n a t i o n of f e r r i c y a n i d e i n K - 1 2 F Bleach (B)

Using an u p r i g h t p i p e t , add 5 . 0 ml sample and 5 m l d i s t i L l e d w a t e r t o a 2 5 0 m l Er lenmeyer f l a s k .

P l a c e on magne t i c s t i r r e r and s t i r a t low s p e e d .

P i p c t 1 0 ml o f 0 . 7 M z i n c ace t c i t e s o l u t i o n and 20 ml o f 3 .0M sodium a c e t a t e b u f f e r i n t o t h e f l a s k .

123

I

A d ~ l 5.0 g r a ~ n s of potassium iodide crystals to t h e solution and dissolve.

Rinse down t h e inside of the flask with distilled water and i~iililediately titrate with 0.100 N sodium thiosulfate solution to p a l e yellow.

Add 5 ml of a standard starch indicator solution and continue titrating until blue color disappears.

Record b u r e t t e r e a d i n g ,

Calculation: 5 . 6 x (ml 0.100 N sodium thiosulfate) =I gm/liter sodium ferricyanide.

Cerimetric Determination of Ferrocyanide in K - 1 2 F Bleach

Add 250 ml distilled water to a 400 ml beaker.

Using an upright pipet add 5.0 ml o f sample to the beaker.

Pipet 10 ml of 7.0 N sulfuric acid to the beaker.

(24)

Add 10 drops of sodium.diphenylamine-sulfonate indicator solution.

Place on magnetic stirrer and titrate with 0.050 ceric s u l f a t e solution.

Record burette reading.

Calculation: 4.84 x (ml 0.050 ceric sulfate) = gm/liter- sodium ferrocyanide.

Spectrophotometric Determination of Ferrocyanide, Modified Kodak Nethod

Using an upright pipet add 10.0 ml of sample to a 100 ml volumetric flask and dilute to volume with distilled water.

Stopper flask and shake to mix the solution thoroughly.

Acidify the solution with concentrated hydrochloric acid (using pH indicator paper) to pH 3 - 4 .

Take 40 ml of the acidified solution and add 2 drops of the ferrous-ferric reagent. Stir immediately.

A l l o w sample to stand for fifteen minutes without further agitation to develop blue color,

Fill one spectrophotometer cell with the solution to which the ferrous-ferric reagent was added.

124

I Fi l l 3 ~ i i . ~ t ~ l l l l l g c c l l w i t h t h e s o l u t i o n t o which t h e f e r r o u s - i c r 1 - i ~ r c a g e n t was n o t added . T h i s i s t h e b l a n k s o l u t i o n .

i Insert b o t h c e l l s i n t o a s p e c t r o p h o t o m e t e r and z e r o t h e b l a n k a t 7 0 0 nm.

bn

Tic

Neasu re t h e a b s o r b a n c e o f t h e b l u e sample a t 7 0 0 nm on t h e s p e c t r o p h o t o m e t e r . * C a l c u l a t i o n : 2 2 . 4 x (Absorbance a t 7 0 0 nm) x ( d i l u t i o n f a c t o r )

* I f a b s o r b a n c e of b l u e s o l u t i o n i s g r e a t e r t h a n 0 . 8 , d i - l u t e 1 0 . 0 ml of t h e a c i d i f i e d sample t o 1 0 0 m l and r e p e a t . I f s o l u t i o n does n o t v i s u a l l y t u r n b l u e r e p e a t t e s t w i t h o u t d i l u t i n g sample.

m g / l i t e r sodium f e r r o c y a n i d e .

S p e c t r o p h o t o m e t r i c D e t e r m i n a t i o n o f F e r r i c y a n i d e a t 4 1 7 nm

F i l l one s p e c t r o p h o t o m e t e r c e l l w i t h t h e s o l u t i o n t o b e a n a l y z e d .

F i l l a ma tch ing c e l l w i t h d i s t i l l e d w a t e r , T h i s c e l l i s t h e b l a n k .

P l a c e b o t h c e l l s i n t h e s p e c t r o p h o t o m e t e r and z e r o t h e blank a t 4 1 7 nm.

Measure t h e a b s o r b a n c e o f t h e sample a t 4 1 7 nm on t h e s p e c - t r o p h o t o m e t e r . *

C a l c u l a t i o n s : 296 x (Absorbance a t 4 1 7 nm) ( d i l u t i o n f a c t o r ) =

S p e c t r o p h o t o m e t r i c D e t e r m i n a t i o n o f Sodium F e r r o c y a n i d e a t 2 2 0 nm


F i l l a ma tch ing c e l l w i t h d i s t i l l e d water .

P l a c e b o t h c e l l s i n t h e s p e c t r o p h o t o m e t e r and z e r o t h e b l a n k a t 2 2 0 nm.

m g / l i t e r sodium f e r r i c y a n i d e .

T h i s i s t h e b l a n k .

Measure t h e a b s o r b a n c e o f t h e sample a t 2 2 0 nm on t h e s p e c t r o - p h o t o m e t e r . *

C a l c u l a t i o n : 1 6 . 7 x (Absorbance a t 220 nm) x ( d i l u t i o n f a c t o r )

* I f t h e a b s o r b a n c e i s g r e a t e r t h a n 0 . 8 d i l u t e 1 0 . 0 m l o f g a m p l e t o 1 0 0 m l and r e p e a t t h e t e s t .

mg/l sodium f e r r o c y a n i d e

125

S p c c t r o p h o t o n e t r i c D e t e r m i n a t i o n o f Fer r - ic -yanide a t 4 6 0 . 5 nm


F i l l a match ing c e l l w i t h d i s t i l l e d water . T h i s i s t h e b l a n k .

P l a c e b o t h c e l l s i n t h e s p e c t r o p h o t o m e t e r and z e r o t h e b l a n k a t 4 6 0 . 5 nm.

Neasu re t h e a b s o r b a n c e o f t h e sample a t 4 6 0 , s nm on t h e s p e c t r o - pho to ine te r . * C a l c u l a t i o n : 2 . 8 5 x (Absorbance a t 4 6 0 . 5 nm) x ( d i l u t i o n f a c t o r ) =

* I f t h e a b s o r b a n c e i s g r e a t e r t h a n 0 . 8 d i l u t e 1 0 . 0 m l o f sample t o 1 0 0 ml and r e p e a t t h e t e s t .

g / 1 sodium f e r r i c y a n i d e . I I !

P r e p a r a t i o n o f F e r r o - f e r r i R e a g e n t

I D i s s o l v e i n 2 0 ml o f d i s t i l l e d water 0 . 7 5 0 g f e r r i c c h l o r i d e and 0 . 7 5 0 g f e r r o u s c h l o r i d e .

Ahd 3 m l c o n c e n t r a t e d h y d r o c h l o r i c a c i d . I

D i l u t e t o 30 ml w i t h d i s t i l l e d water .

APPENDIX: E

The P h o t o g r 3 p h i c P r o c e s s 3nd S o u r c e s o f P o l l u t i o n

The c o l o r r e v e r s a l Ektachroinc p h o t o g r a p h i c p r o c c s s w a s t e e f f l u - e n t i s r e p r c s c n t a t i v e o f p o l l u t i o n problems from t h e p h o t o g r a p h i c i n d u s t r y , b e c a u s c i t c o n t a i n s all t h e t y p i c a l p r o c e s s i n g s o l u t i o n s . The f i l m t r a v e l s t h r o u g h t h e s e r i e s of b a t h s , a s shown i n F i g u r e E - 1 , ( page 1 3 4 ) . Thesc i n c 1 u d e : t h e p r e h a r d e n e r , n e u t r a l i z e r , 1 s t d c v e l o p o r , 1 s t s t o p , w i l to r wash, c o l o r doveloper, 2nd s t o p , w a t e r wash , b l e a c h , f i x e r , w a t e r wash and s t a b i l i z e r .

The f u n c t i o n s of each o f t h e s e s o l u t i o n s a r e d e s c r i b e d i n Tab le E-1.

I t s h o u l d be n o t e d t h a t c o m b i n a t i o n s o f t h e s e s o l u t i o n s a r e used t o make up a l l o t h e r ma jo r p h o t o g r a p h i c p r o c e s s e s . For example, t h e p r o c e s s i n g of c o l o r n e g a t i v e f i l m c o n s i s t s of a c o l o r d e v e l o p e r , s t o p f i x , b l e a c h , f i x and s t a b i l i z e r . a s i m i l a r c o m p o s i t i o n a s t h e c o r r e s p o n d i n g s o l u t i o n s i n t h e Ek ta - chrome p r o c e s s . However, s i n c e t h e s o l u t i o n s t h a t a r e used i n

* t h e s e o t h e r p r o c e s s e s a r e a l l c o n t a i n e d i n t h i s s i n g l e p r o c e s s , t h e Ektachrome p r o c e s s i s d i s c u s s e d h e r e . Any c i t e d problem, w i t h a p a r t i c u l a r s o l u t i o n i n t h a t p r o c e s s , w o u l d t h u s , be a n a l o g o u s t o a p rob lem w i t h t h e same s o l u t i o n i n a n o t h e r p r o c e s s .

These s o l u t i o n s a r e of

T a b l e E - 2 shows t h e r a n g e o f i n d i v i d u a l c h e m i c a l s c o n t a i n e d i n t h e p r o c e s s i n g s o l u t i o n s men t ioned p r e v i o u s l y . h a s b e e n p u b l i s h e d by t h e Eastman Kodak Co.

T h i s i n f o r m a t i o n

T a b l e E - 3 l i s t s t h e a p p r o x i m a t e a v e r a g e c o n c e n t r a t i o n o f i n - d i v i d u a l c h e m i c a l s c o n t a i n e d i n t h e v a r i o u s p h o t o g r a p h i c p r o - c e s s e s . i c a l may b e c o n t a i n e d i n a-number o f p h o t o g r a p h i c p r o c e s s e s ; some i n a l l .

Here i t can r e a d i l y b e s e e n t h a t any one s p e c i f i c chem-

T a b l e E - 4 l i s t s t h e p r i m a r y c h e m i c a l s d i s c h a r g e d f rom t h e pho to - g r a p h i c p r o c e s s t h a t a r e o r g a n i c and t h u s , w o u l d e x e r t an oxygen demand when d i s c h a r g e d t o t h e e n v i r o n m e n t . T h i s l i s t was t a k e n f rom Kodak Pamphlet 5 - 2 8 e n t i t l e d , " D i s p o s a l of P h o t o g r a p h i c Wastes" . A pr imary c o n c e r n i s t h e s p e c i f i c c h e m i c a l s t h a t show a s m a l l f i v e - d a y b i o c h e m i c a l oxygen demand (BOD5) upon - t e s t i n g , b u t a c t u a l l y r e q u i r e a l a r g e amount o f oxygen t o b e t o t a l l y o x i d i z e d t o i n e r t end p r o d u c t s o f c a r b o n d i o x i d e and w a t e r . The f o l l o w i n g g e n e r a l r e a c t i o n d e s c r i b e s wha t i s t e rmed T h e o r e t - i c a l Oxygen Demand (TOD):

The T O D t h u s r e p r e s e n t s t h e t o t a l u l t i m a t e oxygen demand upon t h e e n v i r o n m e n t . A compar ison o f t h e TOD t o t h e BOD5 of t h e i n d i v i d u a l chemica l g i v e s an i n d i c a t i o n o f t h e r e l a t i v e b i o - d e g r a d a b i l i t y o f t h e c h e m i c a l .

127

T ~ b l e E - 5 l i s t s t h e number and p e r c e n t a g e o f t h e 4 5 c h e m i c a l s shown i n T a b l e E - 4 i n c a t e g o r i e s o f t h e p e r c c n t a g c r a t i o of 30Dj t o T O O . 7 0 % o f t h e c h e m i c a l s had 3 BODS l e s s t h a n 1 5 o f t h e i r T O D ; I 'o r 51.2; O C t h c c h e m i c a l s , i t was l e s s t h a n 1 0 % . T h i s i i i c~ i i~s ~ i ~ ~ i ' ~ 1 I * tiic'se c l icmica ls were t r e a t e d i n a m u n i c i p a l

A d i s c u s s i o n of t h e s p e c i f i c p o l l u t a n t chemica l s c o n t a i n e d i n each o f t h e p r o c e s s i n g solutions (as listed in Table E-2) follows: P r e h a r d e n e r I

The p r i m a r y c h e m i c a l s o f c o n c e r n i n a p r e h a r d e n e r a r e aluminum and fo rma ldehyde ; a l t h o u g h n e i t h e r i s c o n s i d e r e d t o b e r e l a t i v e l y

and w a t e r i n a m u n i c i p a l s e c o n d a r y t r e a t m e n t p l a n t , o r w i t h a s t r o n g chemica l o x i d a n t .

Black-and-Whi te D e v e l o p e r s

Hydroquinone and E l o n d e v e l o p i n g a g e n t s i n t h e b l a c k - a n d - w h i t e d e v e l o p e r s a r e b o t h h i g h l y t o x i c t o f i s h , i f d i s c h a r g e d i n t o s t r e a m s . When t e s t e d t o i n d i g e n o u s c a r p ( c y p r i n i d i a ) , Mohanroa, ( 2 7 )

I

t o x i c . Formaldehyde c a n b e e a s i l y o x i d i z e d t o c a r b o n d i o x i d e I

i e t . a l . , found t h a t hydroqu inone and e l o n were t o x i c ( caused f i f t y i p e r c e n t o f a f i s h p o p u l a t i o n t o d i e ) a t 0 . 3 mg/l and 5 mg/l I r e s p e c t i v e l y . However, i n c o m b i n a t i o n t h e c h e m i c a l s showed a I

i

I

s y n e r g i s t i c e f f e c t and t h e e f f l u e n t became t o x i c a t l ower con- c e n t r a t i o n s o f e a c h . T e r h a a r ( 2 8 ) e t . a l . , r e p o r t e d t h a t h y d r o - qu inone and e l o n were e q u i t o x i c a t 0 . 1 mg/l.

Sollman ( 2 9 ) showed t h a t , "Hydroquinone when added t o t h e aquar ium w a t e r was found t o b e a b o u t a hundred t i m e s more t o x i c t h a n p h e n o l , t o g o l d f i s h (and t o Daphnia magna), b u t i s o n l y a b o u t t w i c e a s t o x i c when i n j e c t e d i n t o f i s h o r mammals." West ( 1 0 ) r e p o r t s t h a t , " F o r t u n a t e l y , hydroqu inone i s q u i c k l y b i o d e g r a d e d i n a w a s t e - t r e a t m e n t p l a n t " .

C o l o r Developers

No s p e c i f i c p o l l u t a n t e f f e c t s have been n o t e d f o r c o n s t i t u e n t s in t h e c o l o r d e v e l o p e r s o l u t i o n , r e l a t i v e t o t o x i c i t y t o f i s h and b i o l o g i c a l o r g a n i s m s . Benzyl a l c o h o l i s o n l y s l i g h t l y t o x i c t o f i s h ( i n t h e r a n g e o f 1 t o 1 0 0 m g / l ) , b u t t h e c h e m i c a l i s con- s i d e r e d t o be b i o d e g r a d a b l e and r e p o r t e d t o be t r e a t a b l e i n a s e c o n d a r y p l a n t . E t h y l e n e d i a m i n e , h e x y l e n e g l y c o l and c i t r a - z i n i c a c i d a r e a l s o c o n t a i n e d i n t h e d e v e l o p e r e f f l u e n t . c h e m i c a l s may n o t b e h i g h l y t o x i c , b u t i t a p p e a r s t h e y have a v e r y low b i o d e g r a d a b i l i t y i n a s e c o n d a r y t y p e t r e a t m e n t p l a n t . T h u s , t h e r e may b e some p e r s i s t e n c e o f t h e s e c h e m i c a l s i n t h e e n v i r o n m e n t . ,

1 i

These'

i i i

1 2 8

Goron i s t o x i c t o some a g r i c u l t u r a l p r o d u c t s a t c o n c e n t r a t i o n s above 1 m g / l . i n w a t e r i s g e n e r a l l y u n s a t i s f a c t o r y f o r c r o p s , e s p e c i a l l y i f u s e d f o r i r r i g a t i o n .

C o n c e n t r a t i o n s o f g r e a t e r t h a n 4 m g / l o f boron

Boron l e v e l s of 50 m g / l i t e r have been r e p o r t e d t o r e d u c e t h e e f f i c i e n c y of b i o l o g i c a l t r e a t m e n t s y s t e m s .

A c e t a t e ( f rom a c e t i c a c i d ) i s n o t c o n s i d e r e d t o be t o x i c t o f i s h . I t does e x e r t a h i g h oxygen d e m a n d , i f dumped i n t o a s t r e a m , b u t i s r e a d i l y t r e a t e d i n a s e c o n d a r y p l a n t .

B 1 e a ch e s

F e r r i c y a n i d e i n a w a s t e e f f l u e n t i s c o n v e r t e d t o f e r r o c y a n i d e by t h i o s u l f a t e and o t h e r c h e m i c a l s . . T h u s , o n l y f e r r o and n o t f e r r i c y a n i d e i s n o r m a l l y d i s c h a r g e d from p h o t o g r a p h i c p r o c e s s i n g p l a n t s .

F e r r o c y a n i d e i s n o n - b i o d e g r a d a b l e . Al though t h e compound i s n o t p a r t i c u l a r l y t o x i c , i t i s s l o w l y c o n v e r t e d t o t o x i c f r e e c y a n i d e i n t h e p r e s e n c e o f s u n l i g h t and a i r . Numerous r e p o r t s on t h e t o x i c e f f e c t s o f c y a n i d e s have been made. Some q u o t a t i o n s f o l l o w :

"The e f f l u e n t s f rom t r e a t m e n t p l a n t s r e - c e i v i n g p h o t o - w a s t e must b e d i l u t e d a t l e a s t 1 0 f o l d by r e c e i v i n g s t r e a m s t o s a t - i s f a c t o r i l y d i l u t e undegraded e f f l u e n t c y a n i d e s . (35)

"Under no c i r c u m s t a n c e s may t h e u n t r e a t - e d E A - 4 (Ektachrome) b l e a c h be s a f e l y r e l e a s e d i n t o any s t r e a m , f i e l d o p e r a t i o n s t h i s b l e a c h must b e dumped i n t o a h o l d i n g t a n k . . . . . I '

During m i l i t a r y

( 3 5 )

"An unknown amount o f i r o n c y a n i d e s and t h i o c y a n a t e s . ( l e s s t h a n 3 . 5 mg/l assuming good F l a n t pe r fo rmance ) w i l l b e p r e s e n t in t i l ( > C\ r ' < ? u c n t o f an Ektachrome w a s t e . . ,I , \ : - . , L ;!: l o r i n a t i o n and t h e a c t i o n 01: s~ii.i.i.:;ii; ;;;ay r e s u l t i n s u b s t a n t i a l c o n v e r s i o n o f t h e s e c h e m i c a l s t o h i g h l y t o x i c H C N and CNO- compounds. For t h e s e r e a s o n s , a t l e a s t a t e n f o l d d i l u t i o n of t h e t r e a t m e n t p l a n t e f f l u e n t i s n e c e s s a r y f o r any t r e a t m e n t p l a n t t h e e f f l u e n t of which r o u t i n e l y c o n t a i n s E A - 4 (Ektachrome p h o t o g r a p h i c ) w a s t e , A 1 0 0 f o l d d i l u t i o n i s p r e f e r a b l e . " (35)

, -

, ' *

129

"Dcpcnding o n y o u r l o c a l i t y and y o u r r e - g u l a t o r y a g c n c y , f e r r i c y a n i d e and f c r r o - c y a n i d e c f E l u e n t s may necd t i g h t c o n t r o l . T h e r e f o r c , r c g c n e r a t i o n o f f e r r i c y a n i d e - b e a r i n g b l c a c h e s , where p r a c t i c a l , i s r e c - oinmended, b o t h as a p o l l u t i o n - c o n t r o l measure and f o r economic r e a s o n . " (32 )

T h i o c y a n a t e s may a l s o b e f o u n d i n p h o t o g r a p h i c b l e a c h e s w i t h t h e s e r e s u l t i n g problems :

" T h i o c y a n a t e s a r e t o x i c i n c h r o n i c d o s e s a t r e l a t i v e l y low l e v e l s . T o x i c i t y i s r e l a t e d t o i n t e r f e r e n c e w i t h t h y r o i d f u n c t i o n . P l a n t s 'of t h e c a b b a g e - t u r n i p f a m i l y may b e a b l e t o c o n c e n t r a t e t h i o c y a n a t e s f rom i r r i - g a t i o n w a t e r . " ( 3 6 )

t o r e l ease amounts o f c y a n i d e t o x i c t o a c q u a t i c l i f e a t c o n c e n t r a t i o n s of 2 mg/l o r above" ( 3 6 )

. . . . . t h i o c y a n a t e s decompose i n s u n l i g h t I 1

F i x i n P Baths

S i l v e r i s a n o t h e r s e r i o u s p o l l u t a n t . I n c o n c e n t r a t i o n s a s low a s 0.005 m i l l i g r a m s p e r l i t e r , i t h a s a l e t h a l e f f e c t on b a c t e r i a n e c e s s a r y t o t h e d i g e s t i o n o f sewage. ( 3 0 ) Thus , e v e n minute t r a c e s o f s i l v e r i n t h e p h o t o g r a p h i c e f f l u e n t can b e h a r n f u l t o b i o l o g i c a l t r e a t m e n t p l a n t s o r t o s t r e a m l i f e . I t has b e e n s t a t e d t h a t s i l v e r w i l l p r e c i p i t a t e o u t as s i l v e r h a l i d e i n w a s t e e f f l u e 6 t s and b e removed i n w a s t e t r e a t m e n t p l a n t s . T h i s i s se ldom t r u e , b e c a u s e t h e t r a n s i t t ime from p h o t o g r a p h i c l a b - o r a t o r y t o sewage t r e a t m e n t p l a n t i s i n s u f f i c i e n t t o a l l o w p r e - c i p i t a t i o n t o o c c u r . S i l v e r goes i n t o t h e t r e a t m e n t p l a n t as a s i l v e r complex t h a t w i l l k i l l enough b a c t e r i a t o r e d u c e s i g n i f - i c a n t l y t h e e f f i c i e n c y o f a p l a n t .

Concern ing d i s c h a r g e t o a t r e a t m e n t p l a n t , Greenwel l (31 ) r e - p o r t e d " t h a t s i l v e r i n p h o t o g r a p h i c p r o c e s s i n g e f f l u e n t i s i n a complex f o r m and i s n o t t o x i c t o b i o l o g i c a l t r e a t m e n t sys tems" . However, t h a t d a t a was b a s e d upon a b i o l o g i c a l s y s t e m f o r t r e a t i n g p h o t o g r a p h i c w a s t e s o n l y . LeFebvre and C a l l a h a n r e p o r t e d t h a t s i l v e r d e s t r o y s a c t i v a t e d s l u d g e i n a m u n i c i p a l p l a n t a t v e r y low c o n c e n t r a t i o n s . ( 3 5 ) I t i s s a f e t o assume t h a t n o s i muni- c i p a l p l a n t s now r e c e i v e some s i l v e r and i t may b e a cause f o r r educed p l a n t e f f i c i e n c y . t h e p l a n t w i l l h ave s i g n i f i c a n t t o x i c e f f e c t on t h e a c q u a t i c o r - ganisms o f t h e t r e a t m e n t p l a n t r e c e i v i n g water .

S i l v e r i o n a l s o r e d u c e s B iochemica l Oxygen Demand r e s u l t s by p r e v e n t i n g t h e a c t i o n o f m i c r o o r g a n i s m s . A c o n c e n t r a t i o n of 0 . 0 3 mg/l s i l v e r p roduced a 2 5 % r e d u c t i o n i n BOD measurement , w h i l e a 1 . 0 mg/l c o n c e n t r a t i o n produced an 819 i n t e r f e r e n c e .

I n a d d i t i o n , a n y s i l v e r p a s s i n g t h r o u g h

( 3 0 )

130

1- 1 I ; i i o s ~ i l i n t c 211~1 s u l f i t c a r c n o t t i i r c c t l y t o x i c t o f i s h . ilow- c \ -L ' I ' , i:' i1:iiiipcti i n t o a l i i kc o r s t r c m , t h c s e chemica l s r o b o s y s c i i Lro:ii t h e w n t c r and "suffocate" n c q u a t i c l i i e . I n t h a t c a s e , ti:c chcni icn ls a r e i n d i r c c t l y t o x i c t o t h e a c q u a t i c l i f c . If duiiiped t o a i i iuii icipal p l a n t hav ing p r i m a r y and s e c o n d a r y t r ea t i i i c i i t , t h e s e c h e i i ~ i c a l s r e c e i v e a d e q u a t e t r e a t m e n t . IIowcver, t l i i o u s u l f a t e and s u l f i t e have h i g h c h l o r i n e demands. Thus, t h e y inay r o b t h e d i s i n f e c t a n t power o f c h l o r i n e , u s e d t o k i l l b a c t e r i a i n e f f l u e n t f rom t h e t r e a t m e n t g l a n t . Many p h o t o f i n i s h e r s a r e a f f e c t e d by c h l o r i n e demand laws.

Hendr i ckson and Durbin (34) have t h u s r e p o r t e d :

"The t h i o s u l f a t e i n t h e f i x i n g s o l u t i o n , even a f t e r t h e s i l v e r h a s been removed, a l s o c r e a t e s a problem i n t h e t r e a t m e n t p l a n t . I t i s a s t r o n g r e d u c i n g a g e n t which r e a c t s w i t h t h e d i s i n f e c t a n t u sed i n t h e p l a n t . \\'hen l a r g e q u a n t i t i e s o f f i x i n g s o l u t i o n a r e dumped, a s t h e y some- t i m e s a r e , t h e m u n i c i p a l p l a n t o p e r a t i o n i s u p s e t b e c a u s e t h e t h i o s u l f a t e h a s t a k e n a l l t h e c h l o r i n e n o r m a l l y used t o p u r i f y t h e w a s t e . I '

Ammonium i o n , c o n t a i n e d i n some f i x e r s , i s a n u t r i e n t f o r a l g a e . I f t h e pH i s t o o h i g h (>pH 8 ) , ammonium i o n forms ammonia. Ammonia i s a l s o used as an a g r i c u l t u r e f e r t i l i z e r and i s a common i n g r e d i e n t i n d o m e s t i c sewage . D i s p o s a l t h r o u g h t h e m u n i c i p a l w a s t e t r e a t m e n t p l a n t s h o u l d be e f f e c t i v e .

Some s p e c i f i c r e p o r t e d problems w i t h f i x e r s f o l l o w :

" D e s i l v e r e d EA Ektachrome ( p h o t o g r a p h i c ) w a s t e c a n n o t b e d i s p o s e d o f w i t h o u t de- g r a d a t i v e t r e a t m e n t u n l e s s such a c t i o n i s j u s t i f i e d as d e f i n e d i n E x e c u t i v e Or- d e r s 1 1 5 0 7 and 1 1 5 1 4 ( N a t i o n a l C r i s i s ) . When s o j u s t i f i e d , EA-4 w a s t e may b e i n t r o d u c e d u n t r e a t e d i n t o s t r e a m s w i t h a volume o f a t l e a s t 3.4 c u b i c f e e t p e r s e c o n d ( C F S ) . . . , I t ( 3 5 )

" D e s i l v e r i n g E A - 4 (Ektachrome) f i x e r b a t h p r i o r t o d i s p o s a l i s mandatory r e g a r d l e s s o f t h e d i s p o s a l t e c h n i q u e . N o n - d e s i l v e r e d waste i s e x t r e m e l y t o x i c t o a l l b i o l o g i c a l s y s t e m s t e s t e d . " (35 )

131

"(Ektacliroine) E A - 4 w a s t c m u s t b e d c s i l v e r - cd p r i o r t o s t r e a m d i s p o s a l . D i s p o s a l o f wastes c o n t a i n i n g s i l v e r c o n t e n t , cvcn f o r a s h o r t p e r i o d w i l l r e s u l t i n s e r i o u s p o l l u t i o n . " (35 )

"The e x t r e m e t o x i c i t y of n o n - d e s i l v e r e d E A - 4 (Ektachrome) w a s t e t o a c t i v a t e d s l u d g e o rgan i sms i s c a u s e d by t h e a c c u m u l a t i o n o f s i l v e r i n t h e s l u d g e . ' ' ( 3 5 )

" S i l v e r removal i s a mandatory r e q u i r e m e n t f o r p h o t o w a s t e b e i n g i n t r o d u c e d i n t o a b i o l o g i c a l t r e a t m e n t sys tem. ' ' ( 3 5 )

. , . , ( f i x ) d i s p o s a l p r e s e n t s a s e r i o u s p o l l u t i o n problem i n v iew o f t h e f a c t t h a t i n l a r g e s c a l e i n s t a l l a t i o n s t h e volume o f f i x i n g s o l u t i o n t o b e d i s c a r d - ed can b e v e r y l a r g e and f u r t h e r i n view o f t h e f a c t t h a t t h e t h i o s u l f a t e i o n which i s p r e s e n t i n t h e s o l u t i o n f o l l o w i n g r e c o v e r y o f t h e s i l v e r i s a ma jo r p o l l u t a n t b e c a u s e o f i t s h i g h oxygen demand."

f t

"A p h o t o g r a p h i c l a b o r a t o r y i n a modera t e s i z e d sewage s y s t e m would a l m o s t c e r t a i n - l y p o s e a c o n t i n u i n g t h r e a t t o a n a c t i v a t e d s l u d g e p l a n t o r t o sewage d i g e s t i o n ..." ( 3 6 )

"Sodium t h i o s u l f a t e s u s e d i n l a r g e q u a n t i t i e s i n p h o t o g r a p h i c p r o c e s s i n g i s a s t r o n g r e - duc ing a g e n t and c o u l d a c c e l e r a t e t h e r e - d u c t i o n o f f e r r i c y a n i d e - t o HCN." (36)

. . . . t h e l e t h a l c o n c e n t r a t i o n o f s i l v e r may be as low a s 0 . 0 0 5 mg/l f o r f i s h and 0 . 0 1 mg/l f o r b a c t e r i a s o t h a t e v e n minu te t r a c e s o f s i l v e r i n p h o t o g r a p h i c e f f l u e n t c o u l d b e h a r m f u l t o b i o l o g i c a l t r e a t m e n t p l a n t s or t o r i v e r l i f e . ' ' ( 3 0 )

II

N e u t r a l i z e r s

N e u t r a l i z e r s a r e u s u a l l y of l i t t l e c o n c e r n as p a r t o f a P h o t o g r a p h i c was te e f f l u e n t . A c e t a t e i s t h e p r i m a r y o r g a n i c c h e m i c a l and i t has b e e n d i s c u s s e d p r e v i o u s l y u n d e r S t o p B a t h s .

1 3 2

S t n b i l i z c r s

Zinc is t h c p r i m a r y contnr i i inant o f t h e stabiliscr. I t h a s been r e p o r t e d ( 3 0 ) as b e i n g t o x i c t o f i s h i n t h e r a n g c o f 1 - 2 i n g / l . T h e c r i t i c a l l e v e l in raw sewage , f o r continuous doses on b i o l o g i c a l sys tc ins , i s 5 - 1 0 mgjl. ( 3 0 ) . The c r i t i c a l l e v c l i n raw sewage f o r a f o u r - h o u r shock d o s e , g i v i n g a s i g n i f i c a n t r e d u c t i o n in a e r o b i c t r e a t m e n t , i s 160 mg/l; w h i l e t h e maximum c o n c e n t r a t i o n o f z i n c p t h a t w o u l d n o t i m p a i r a n a e r o b i c d i g e s t i o n Q$ prilnary and s e a m d a y zreatment i a n t s l u d g e s t i s 10 mg/l . ( 3 0 ) Zinc i ~ f i w i i l a l s o i n t e r f e r e with I? !i d d i e m i e a l O X Y ~ E A Dejjafid (BOD) measurements . T e b b u t s ( 3 0 ) r e p o r t s t h a t a c o n c e n t r a t i o n of 1 mg/l r e d u c e s BOD measurement by 8 % , w h i l e a 7 . 0 mg/lpconcen- t r a t i o n p r o d u c e d a 2 5 % i n t e r f e r e n c e ,

133

P r e h a r d c nc r

Neutralizer

1st Developer

1st stop

1st Wash

C o l o r Developer

2nd Stop and Hardener

2nd Wash

Bleach

F i x

3rd Wash

Stabilizer

c

134

a E 0 Ll

t-i

I w Q) k 3 M

. I 4

c4

S T E P S . IN COLOR PROCESS

The c o m p o s i t i o n o f t h e s o l u t i o n s u s e d i n t h e c o l o r p r o c e s s a r e shown i n Tab le E - 2 . The f u n c t i o n of each s o l u t i o n i s as f o l l o w s :

a . P r e h a r d e n e r - Reduces e m u l s i o n s w e l l i n g d u r i n g p r o c e s s i n g ,

b , N o u t r a l i a r - Neutralizes h a r d e n i n g a g e n t s carr ied over by t h e f i l m t o p r e v e n t t h e i r r e a c t i o n w i t h t h e c o u p l i n g a g e n t s i n t h e f i l m .

c. F i r s t Developer - Exposed a r e a s a r e d e v e l o p e d t o g i v e a b l a c k - a n d - w h i t e n e g a t i v e s i l v e r image.

F i r s t S t o p Bath - S t o p s a c t i o n of F i r s t Developer and r e - duces emul s ion s w e l l .

d .

e . Water Wash - F l u s h e s a c i d s o l u t i o n o f f o f t h e f i l m .

f . C o l o r Developer - Develops a l l r e m a i n i n g s i l v e r h a l i d e , r e s u l t i n g i n p o s i t i v e images .

g . Second S t o p Bath - S t o p s a c t i o n o f t h e C o l o r Deve lope r .

h . Water Nash - F l u s h e s t h e a c i d s o l u t i o n o f f o f t h e f i l m .

i. Bleach - A l l m e t a l l i c s i l v e r i s c o n v e r t e d t o s i l v e r h a l i d e .

j ,; F i x i n g Bath - S i l v e r h a l i d e s a r e removed by r e a c t i o n w i t h t h i o s u l f a t e .

k. Water Wash - F i x i n g b a t h f l u s h e d o f f o f f i l m

1. S t a b i l i z i n g Bath - Hardens e m u l s i o n and s t a b i l i z e s P y e image.

135

w

d c;1 5l a

C b a c! M h

c, d cd v)

I I

n

i

I

l

I

0 r(

.- .

TABLE E - 2

(Cont inuecl)

_ -

__ - - __ - - CONCENTRATION IW I J j>! G R h l l S PER LITI ’R TYPE OF SOLUTION -

- __ - AND pH R A N G E 1 0 t o 100 1 t o 16 LESSTIAN 1 __ -.__

S t o p B a t h s S u l f a t e Aluminum pH 2 t o 4 A c e t a t e B o r a t e

C i t r a t e - - - _ - _

F e r r i cy a n i d e F e r r i c y a n i d e B i c a r b o n a t e B l e a c h e s F e r r o c y a n i d e N i t r a t e

P

-.I w pH 5 t o 8

F i x i n g B a t h s C h l o r i d e pH 4 t o 8 T h i o s u l f a t e

Ammonium

Aluminum B i s u l f i t e B i c a r b o n a t e B o r a t e A c e t a t e Bromide S i l v e r t h i o s u l f a t e complex F e r r o c y a n i d e Formal i n Se qu e s t e r i ng a g c i i t

TABLE E - 2

(continued)

TYPE OF 1 'il'ION CONCENTRATION RANGE IN GRANS PER LITER LESS THAN 1 A N D pIl - 4 1 to 10

Neutrali PH 5

Bromide Sulfate Hydroxy 1 ami ne

Acetate

S t a b i l i I L : pH 7 to 9 Formaldehyde

Zinc Sulfate Phosphate Citrate Benzoate Sequestering agent

We t t i n g agent

___

T A B L E E - 3

APPROXIMATE C I I M I C A L CONCEN’TIb lTIONS IN

EFFLUENTS FRObl P1101’0 PROCESSING bIACII IXES

(mg/ l u n l e s s o t h e r w i s e n o t e d )

1 2 3 4 5 6 7 8 9

E k t a - E k t a - B/W B / N B/;$ c- 2 2 P r i n t - C E - 4 P r i n t - R F i l m P a p e r ME-4 E C O - 2 Revers: : l

Aluminum I o n Ammon i um I o n

h - ~ H o r 3 x UJ Bromide I o n w

C a r b o n a t e I o n F e r r o c y a n i d e N i t r a t e I o n P h o s p h a t e I o n S u l f a t e I o n S u l f i t e I o n T h i o c y a n a t e I o n Thiosulfate I o n Zinc I o n Chromium ( + 6 ) A c e t a t e I o n B e n z y l A l c o h o l C o l o r D e v e l o p e r C D - 3 E l o n Fo r ma 1 de h y d e Hydroqu inone Mydroxy l Amine S u l f a t e

Volume ( l / m i n )

BOD

70 670 1 8 0

90 1 4 0 240

190

2 2 0

800 1 2 0 1 2 0

3 30

70

820

20 80

3 0 0 60

310 160 3 1 0

1 3 0 210

1 0 0 0 30

140 1 6 0

50

360

4 0

30

1 2 4 0

40 1 0 90

110 290

1 2 0 2 0 0 300

1 0 1 2 0

250 2 0 60 40 60 60 2 0

30

380

1 0 1 0

20 1 0 50 70 20 2 1 0 70

4 0 60 5 0

1 0 0 130 . 2 2 0

1 6 0 130 710 10

170 3 2 0 160 80 20 1 0

190 50 1 0 20 I 10 30

60 20 30

4 30 240 4 7 0

2 5 0 1 0

4 0 0 9 1 0

1 1 1 0

8 5 0 1 3 8 0 2140

50 800

1 8 7 0 1 9 0 4 3 0

440 39 0 1 9 0

2 0

2570

260 3 0 1 0

4 0 0 600 1 3 0 1110

810 2600 30 1300 1 6 0

810 4 8 0 70

2 0 1920 2 2 0

2 30 2 1 0

4 6 0 10 1 9 0 2 0 1 9 0

7 0 30

2 2 7 0 3 5 0

n k 0

r-4 0 U (d d h

F1

k 0 rl 0 U .d M 7 P-4

e

n

k 0 r(

0 U (d cei M G

k 0 l-4 0

n

r: U

-3 0

L 4 v

e, > *d c, rd M e, 2

k 0 d 0 U

r(

n c, d 3 3:

U

c, F: *d k G cj c, jc w

I

v

k a, G cd PI

k 0 ri 0 U

N

m

I d

w 0 E 0 k rc U rd c, & w v

m 0 7j .ri ri m ri cj vr k 0 > 0 d

k 0

l-4 0 U

M

n p: I

c, c

.r(

k !a (d c,

w v

k 0 c4 cj k

d cj m k 0 > r 3 p: k 0

l-4 0 U

-3-

n (v

0 U w

I

2 0 k s: U cd c, 24 w v, v, a, V 0 k 14 v

E l-4 .rl c4

e, .d > 0

ri (d v) k 0 > 0 d k 0 rl 0 U

Q)

1 4 0

T A D L E E - 4

B io ihcn1 ica l O s y g c n Dcmand o f Chemicals Uscd in

Pliorogi'npliic Processing Compared t o Theoretical Oxygen Demand (From Pamphlet J-28)

Kodnk Anti-Calcium No. 3 Kodak Anti-Fog No. 1 Kodak Anti-Fog No. G Kodak Anti-FoE No. 7 Balancing Developing Agent BD- 82

BD- 86 BD- 89

Benzyl A l c o h o l B u t ane d i on e Carbowax 1,540 Carbowax 4000 Citrazinic Acid Citric Acid, bfonohydrate Color Developing Agent CD-1

CD- 2 CD- 3 CD- 4 CD- 5

Coupling Agent C-16 bl- 40 y - 5 4

Dicolanine Elon Developing Agent Ethylene Diamine Formalin Formic Acid Glacial Acetic Acid Hardening Agent -HA-2 Hardening Agent -HA-1 Hexylene G l y c o l Hydroquinone Methelon Developing Agent Phenidone Kodak Potassium Ferricyanide Revers a1 Agent RA- 1 Sodium Acetate Sodium Bisulfate Sodium Citrate (2H20) Sodium Ferrocyanide, Decahydrate Sodium Formate Sodium Isoascorbate Sodium Sulfite Sodium Thiosulfate ( 5 H 2 0 ) Stabilizing Agent-SA-1 Sodium Thiocyanate

Tlieor c t i ca 1 Oxygen Demand TOD (ultimate) -5 BOD

it

0 . 9 0 2 . 9 8 2 . 1 5 2.70 1 . 1 3 1 . 9 1 2 . 7 0 2 . 5 5 1 . 6 8 3 . 5 9 3 . 6 2 1 . 3 6 0 . 6 8 2 . 5 3 2 . 6 8 1 . 5 8 1 . 9 1 2 . 2 8 2 .47 1 . 4 4 2 . 2 0 1 . 9 6 1 . 8 6 3 . 4 7 0 . 6 2 0 . 2 3 1 . 0 6 2 .22 0 . 6 0 2 . 3 1 . 9 1 . 9 8 2 .67 1 . 5 2 3 . 5 0 0 . 7 8 0 . 1 6 0 . 4 9 1 . 0 6 0 . 2 4 1 . 2 5 0 . 1 2 0 . 3 2 1 . 5 4 1 . 5 8

A

0 . 0 0 3 0 . 0 4 0.05 0 . 0 3 0.07 0 . 1 4 0 . 1 7 1 . 8 0 0 . 5 5 0 . 0 3 0 . 0 2 0 . 0 0 3 0.4 Oil3 0 . 1 4 0.10 0.13 0 . 0 8 0 . 0 3 0 . 0 3 0 . 0 3 0 . 1 5 0 .70 0 . 0 3 0 . 3 7 0 . 0 2 0 .74 0 . 0 7 0 . 0 1 0 . 0 0 3 1.1 0 . 1 6 0.16 0 . 0 0 3 0 . 0 3 0 . 5 8 0 . 1 6 0 . 3 5 0 . 0 0 3 0 . 0 1 6 0 . 2 9 0 . 1 2 0 . 2 0 . 0 3 0 . 0 3

BODS ?'OD ~

x 100

0 . 3 3 1 . 3 4 1 . 4 0 1.11 5 . 3 7 . 3 6 . 3

6 6 . 3 3 3 . 3 ' 0 . 8 4 0 . 5 5 0 . 2 2

5 . 1 5 5 . 6 0 6 . 3 3 6 . 8 3 . 5 1 . 2 2 . 1 1 . 3 7 7 . 6 5

5 9 . 0

3 7 . 6

5 9 . 5 9 . 1

6 8 . 0 3 . 6 1 . 6 7 0 . 1 3

58.0 8 . 1 6 . 0 0 .20 0 . S 6

. 8 6 5

7 3 . 5 1 0 0 . 0

6 5 . 0 0 . 2 8 8.0

2 3 . 2 1 0 0 . 0

6 2 . 5 1 . 9 5 1 . 9 0

* Unit weight of oxygen demand per unit weight of chemical (i.e gm OZ/gm)

161

TABLE E - 5

RELATIVE INEFFECTIVENESS OF BIOLOGICAL

TYPE OF TREATMENT OF PHOTOGRAPHIC CHEMICALS

P e r c e n t Range

0 . 0 - 0 . !I !.I

1.9 - 9.99

10.0 - 4 9 . 9

5 0 . 0 - 8 9 . 9

9 0 . 0 - 1 0 0

Number o f Chemicals in P e r c e n t of Each C a t e g o r y T o t a l

9

2 3

3

8

2

5 1 . 2

6 . 7

1 7 . 7

4.4

45 100.0

142

r-. i : - c a t ; ? e n t o f P h o t o g r a p h i c Waste O u t s i d e o f P r o c e s s i n g P l a n t ~

T h e f o l l o w i n g s e c t i o n was e x t r a c t e d i n i t s e n t i r e t y f r o m Pamphlet J-ZS, " D i s p o s a l o f P h o t o g r a p h i c Wastes" by Eastman Kodak Co. unde r t h e s e c t i o n e n t i t l e d : Methods o f Waste T r e a t m e n t ,

IIStorm s e w e r s o r su r f ace d r a i n a g e f o r d i s - c h a r g i n g p r o c e s s i n g e f f l u e n t s w i t h o u t t r e a t - ment s h o u l d n o t b e u s e d b e c a u s e o f t h e l i k e l i h o o d o f v i o l a t i n g t h e s t ream s t a n d - a r d i n t o which t h e sewer w a s t e f l o w s . ' t

" S e p t i c t a n k s a r e b i o l o g i c a l s y s t e m s b u t a r e n o t recommended f o r d i s p o s a l of p h o t o - g r a p h i c p r o c e s s i n g w a s t e s . S e p t i c t a n k s do n o t d e g r a d e t h e wastes s u f f i c i e n t l y , a r e g e n e r a l l y d e s i g n e d f o r sma l l e r volumes , p roduce t o x i c and odorous p r o d u c t s , can - n o t be i n s t a l l e d i n a l l l o c a t i o n s , and r u n t h e r i s k o f c o n t a m i n a t i n g ground w a t e r s . S e p t i c t a n k s a r e a n e r o b i c systems, t h a t i s , t h e b i o l o g i c a l p r o c e s s p r o c e e d s w i t h o u t a i r , ' I

"An a e r a t e d l agoon i s n o t a p r a c t i c a l s o l u t i o n f o r many p r o c e s s o r s b e c a u s e a l a r g e a r e a o f l a n d i s r e q u i r e d . I t i s a l s o a s a f e t y h a z a r d and r u n s t h e r i s k o f i n c o m p l e t e d e g r a d a t i o n , t h e c r e a t i o n o f o d o r s , and c o n t a m i n a t i o n o f ground w a t e r s . However, i f t h e l a g o o n i s l a r g e enough, i s a e r a t e d , a n d h a s an imperv ious l i n e r , i t may b e s a t i s f a c t o r y . The o v e r f l o w s h o u l d b e checked t o i n s u r e t h a t i t d o e s n o t ' c o n t a m i n a t e t he s t r e a m i n t o which i t f l o w s . "

"Deep-well i n j e c t i o n i s l e g a l i n some s t a t e s , b u t o n l y a f t e r c a r e f u l s t u d y h a s been made t o p rove t h a t t h e r o c k s t r u c - t u r e o f t h e a r e a i s s u c h t h a t t h e r e i s no p r o b a b i l i t y o f c o n t a m i n a t i n g ground w a t e r s . The re i s a lways t h e i n h e r e n t dange r o f c o n t a m i n a t i o n o f g r o u n d w a t e r s . Fu r the rmore , t h e c o s t o f i n v e s t i g a t i n g , l e t a l o n e c o s t of d r i l l i n g a n d o p e r a t i n g t h e w e l l , i s e x t r e m e l y h i g h . However, Bea le A i r Force Base i n C a l i f o r n i a has t h r e e i n j e c t i o n w e l l s f o r i t s p h o t o g r a p h i c p r o c e s s i n g w a s t e s . "

143

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" O I L til'\ b , ~ > is o i O L I ? * L \ ~ ! ) L \ i.i.iiic1ltill. wosk, we rcconiuic1lJ t r c , i t i n g processing effluents i n ail a c r o b i c . b i o l o g i c a l w a s t e t r e a t m e n t p l a n t . s y s t c m d c s t r o y s m o s t oxygen demanding chem- i c a l s comiiion t o p h o t o g r a p h i c p r o c e s s i n g e f f l u e n t s j u s t a s i t d e s t r o y s d o m e s t i c s a n i t a r y w a s t e s . The p l a n t i s somet imes r e f e r r e d t o a s a s e c o n d a r y p l a n t , t h e p r i m a r y p l a n t b e i n g f o r t h e p u r p o s e o f o n l y s e p a r a t i n g s o l i d s f rom t h e w a s t e . Laws a r e b e i n g f o r m u l a t e d o r a r e a l r e a d y i n e f f e c t i n v i r t u a l l y a l l s t a t e s i n t h e U n i t e d S t a t e s t o r e q u i r e t h e e q u i v a l e n t o f s e c o n d a r y t r e a t m e n t of a l l w a s t e s e n t e r i n g a s t r e a m o r l a k e . A b i o l o g i c a l t r e a t m e n t p l a n t makes u s e o f t h e same t y p e o f a e r o b i c b i o l o g i c a l a c t i v i t y t h a t would o c c u r i f t h e w a s t e were t o f l o w down a s t r e a m , e x c e p t t h a t t h e w a s t e s a r e d e g r a d e d i n a t r e a t m e n t p l a n t i n a m a t t e r o f h o u r s , r a t h e r t h a n t h e days t h a t a r e r e q u i r e d i n s t r e a m s . i n s u r e s r a p i d a e r o b i c d e g r a d a t i o n i n a w a s t e - t r e a t m e n t p l a n t . "

"One t y p e o f s e c o n d a r y sys t em i s c a l l e d a t r i c k l i n g f i l t e r , s o named b e c a u s e t h e a e r a t e d w a s t e t r i c k l e s o v e r a l a r g e s u r f a c e o f s m a l l r o c k s o r p l a s t i c s o t h a t t h e d e - s i r e d b i o l o g i c a l d e g r a d a t i o n i s accompl i shed . "

"Another common t y p e o f s e c o n d a r y p l a n t i s t h e a c t i v a t e d - s l u d g e p l a n t , u s u a l l y b u i l t i n l o n g r e c t a n g u l a r t a n k s . I t u t i l i z e d b i o l o g i c a l a c t i o n b r o u g h t a b o u t by a i r , b a c t e r i a and n u t r i e n t s . Some o f t h e d e - g r a d a t i o n p r o d u c t s a r e removed a s g a s e s , some r e m a i n d i s s o l v e d , and some p r e c i p i t a t e a s a s l u d g e . M u n i c i p a l t r e a t m e n t p l a n t s d r y t h e s l u d g e and g e n e r a l l y u s e i t f o r l a n d - f i l l . More comple t e b i o l o g i c a l de - g r a d a t i o n may be a t t a i n e d by r e c i r c u l a t i n g some o f t h e s l u d g e and e x t e n d i n g t h e a e r a t i o n t i m e . O r g a n i c compounds, i f d e g r a d e d com- p l e t e l y w i l l p r o d u c e c a r b o n d i o x i d e , w a t e r and o t h e r p r o d u c t s . P r o c e s s i n g c h e m i c a l s s u c h a s hypo a r e a l s o d e g r a d e d by t h e b i o l o g i c a l p r o c e s s . "

The b i o l o g i c a l d e g r a d a t i o n i n t h e

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I 1 . j > ' L i ~ c b i o l o g i c a l t r c ; ~ t i n e i l t p l a n t i s t h e

litns t C x p c n s i v c nicthocl known Cor des t r u c - t i o i i o i mixed osygcn-demanding w a s t e s , m o s t o f which a r e o r g a n i c . P r o p e r o p e r - a t i o n of a p l a n t r e q u i r e s c a r e f u l a t t e n - t i o n . The l a r g e m u n i c i p a l p l a n t s c a n o p e r a t e a t much lower c o s t p e r u n i t amount o f w a s t e t h a n s m a l l p l a n t s . I t i s p r o b a b l y l e s s e x p e n s i v e t o pay a muni- c i p a l i t y t o h a n d l e t h e w a s t e f rom a p r o c e s s i n g l a b o r a t o r y compared w i t h con- s t r u c t i n g and o p e r a t i n g one f o r t h e e x c l u s - i v e u s e of t h e l a b o r a t o r y . "

I n - P l a n t T rea tmen t v i a Recovery and R e c i r c u l a t i o n o f P o t e n t i a l l y T o x i c Ivaste M a t e r i a l s .

I n - p l a n t t r e a t m e n t o f p r o c e s s w a s t e s a p p e a r s t o b e t h e b x s t method o f r e d u c i n g p o l l u t i o n o f c h e m i c a l s ' t h a t :

- c a n n o t b e t r e a t e d i n common t r e a t m e n t p l a n t s ( n o n - b i o d e g r a d e a b l e s h a v i n g a BOD5 l e s s t h a n 10% of t h e i r T O D : (See T a b l e E - 4 ) and

- a d v e r s e l y a f f e c t t h e t r e a t m e n t method ( f o r b i o l o g i c a l p l a n t s : t h i o s u l f a t e , i r o n , b o r o n , s i l v e r , z i n c and t h i o c y a n a t e ) .

S i l v e r Recovery and F i x e r Reuse

The p r o f i t a b i l i t y o f s i l v e r r e c o v e r y from f i x i n g b a t h s i n p r o - c e s s i n g p l a n t s h a s b e e n w e l l known f o r many y e a r s . economic c o n s i d e r a t i o n s a r e t h e s u b s t a n t i a l r e t u r n f o r t h e r e - c o v e r e d s i l v e r , a n d c h e m i c a l s a v i n g s t h a t a r e p o s s i b l e by u s i n g l e s s f i x e r . P o l l u t i o n aba temen t b e n e f i t s a l s o r e s u l t , i n t h a t l e s s s i l v e r and l e s s f i x a r e sewered .

The pr ime

By m a i n t a i n i n g low amounts o f s i l v e r i n t h e f i x i n g b a t h , t h e f i l m f i x e s e a s i e r and more c o m p l e t e l y , and t h e s u b s e q u e n t wash s t e p becomes more e f f i c i e n t . t h a t i s d i s c a r d e d w i t h a r e c o v e r y s y s t e m p l u s t h e r e d u c e d amount of s i l v e r i n t h i s w a s t e s o l u t i o n i s c o n s i s t e n t w i t h i n d u s t r y \ s e f f o r t t o r e d u c e p o l l u t i o n . f i x e r i s r e u s e d , . t h e t o t a l volume o f s o l u t i o n i s r e d u c e d con- s i d e r a b l y , t h u s p e r m i t t i n g l e s s f r e q u e n t mixing a n d / o r p o s s i b i l i t y of smaller s t o r a g e t a n k s .

The lower amount o f w a s t e f i x e r

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I n f i x i n g b a t h s , sodium t h i o s u l f a t e (hypo) i s u s e d t o f i x t h e image

- - Ag+ f S 2 Q 3 + (Ag S z O j ) - s o l u b l e

by c o n v e r t i n g t h e undeve loped , i n s o l u b l e , s i l v e r h a l i d e t o a s o l u b l e complex ( s e e e q u a t i o n 4 7 ) . T h i s s o l u b l e complex d i f - fuses o u t o f t h e p h o t o g r a p h i c e m u l s i o n i n t o t h e f i x i n g b a t h . A s t h e f i x i n g b a t h i s u s e d , i t becomes a v e r y complex m i x t u r e . I n a d d i t i o n t o t h e o r i g i n a l components o f t h e f i x i n g b a t h , a u s e d b a t h c o n t a i n s : s o d i u m f e r r o c y a n i d e , sodium s u l f a t e , sodium b romide , g e l a t i n e , complex s i l v e r s a l t s , and v a r y i n g amounts of p r a c t i c a l l y a l l o f t h e c h e m i c a l s u s e d i n p r o c e s s i n g t h e m a t e r i a l . T h e r e f o r e , any method o f r e c o v e r y h a s t o make a l l o w a n c e s f o r t h e s e i n t e r f e r i n g s u b s t a n c e s . F o r t u n a t e l y , s i l v e r i s f a r r e - moved, in t h e e l e c t r o m o t i v e s e r i e s , f r o m any o t h e r m e t a l l i c r a d i c a l i n t h e s o l u t i o n . Most r e c o v e r y methods t a k e advan tage of t h e n o b l e n a t u r e o f s i l v e r .

B a s i c a l l y , t h e r e a r e two methods o f s i l v e r r e c o v e r y : chemica l and e l e c t r o l y t i c . The c h e m i c a l methods i n c l u d e p r e c i p i l a t i o n , m e t a l - l i c r e p l a c e m e n t , and i o n exchange t e c h n i q u e s . The e l e c t r o l y t i c methods. a r e more common i n p r e s e n t p r o c e s s i n g p l a n t s , b e c a u s e t h e y a r e c l e a n e r , u s u a l l y r e q u i r e l e s s o p e r a t i n g l a b o r , and p e r m i t t h e r e u s e of t h e f i x i n g b a t h a f t e r d e s i l v e r i n g , w i t h p r o p e r c h e m i c a l a d d i t i o n s . The f o l l o w i n g f a c t o r s a f f e c t t h e p u r i t y o f s o l u t i o n s t o be r e u s e d and t h e p u r i t y o f s i l v e r c o l l e c t e d :

1. A g i t a t i o n : A g i t a t i o n i s r e q u i r e d s o t h a t new, s i l v e r l a d e n s o l u t i o n i s a lways i n c o n r a c t w i t h t h e c a t h o d e s . I n s u f f i c i e n t a g i t a t i o n r e s u l t s i n a b l a c k e n e d o r s u l f i d e d d e p o s i t on t h e c a t h o d e s . A b a d l y s u l f i d e d d e p o s i t f o u l s t h e c a t h o d e s and r e s u l t s i n a s o f t d e p o s i t , t h a t may d r o p o f f and b e l o s t i n t h e r e c o v e r y c e l l .

S o l u t i o n pH: e n t , b u t pH changes i n t h e r a n g e 7 . 0 t o 1 0 . 0 have l i t t l e e f f e c t . I n a n a c i d s o l u t i o n , t h e p l a t e d s i l v e r t e n d s t o b e w h i t e even though t h e e f f i c i e n c y i s low. T h i s i s due t o t h e f a c t t h a t t h e s u l f i d e p roduced goes o u t o f s o l u t i o n i n t h e form o f hydrogen s u l f i d e g a s . I n a l k a l i n e s o l u t i o n s , t h e p l a t e d s i l v e r s u l f i d e s e a s i l y , y e t a s l i g h t l y darkened s i l v e r p l a t e may s t i l l p roduce a h i g h c u r r e n t e f f i c i e n c y . A t a pH o f 1 2 , t h e p l a t e d s i l v e r t u r n s brown ( s u l f i d e s ) a t any v o l t a g e .

t o produce a smooth s i l v e r d e p o s i t on t h e c a t h o d e s . e l e c t r o l y t i c a l l y n e u t r a l p a r t i c l e c a n be o c c l u d e d i n t h e

. s i l v e r a s i t d e p o s i t s on t h e c a t h o d e . When t h i s o c c u r s , t h e s i l v e r d e p o s i t w i l l fo rm o v e r t h e p a r t i c l e , p r o d u c i n g a s p o t

2 . Acid and a l k a l i n e f i x i n g b a t h s a r e q u i t e d i f f e r -

3 . S o l u t i o n F i l t r a t i o n : The s i l v e r b e a r i n g s o l u t i o n i s f i l t e r e d An

146

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oLr slia-i.11 c u r v n t u r c . C u r r c n t d e n s i t y w i l l b e h i g h e r a t t h i s v o i n t : f i - i . s t , c a u s i n g s i l v e r t o d e p o s i t f a s t e r a t t h e p o i n t t h n n on the r c s t ' o f t h e c a t h o d e and E i n a l l y , i n i t i a t i n g t h e s u l f i d i n g a c t i o n which f o u l s t h e p l a t e .

C u r r e n t Density: The maximum c u r r e n t d e n s i t y depends on a g i t a t i o n . 'Che i n d e p e n d e n t v a r i a b l e i s v o l t a g e . I f t h e v o l t a g e i s k e p t above a minimum a l l o w a b l e , v a l u e , an i n c r e a s e i n a g i t a t i o n may be 'used t o o b t a i n a h i g h e r c u r r e n t d e n s i t y .

E l e c t r o d e s : The m a t e r i a l u s e d i n t h e c o n s t r u c t i o n o f t h e e l e c t r o d e s i s i m p o r t a n t . G r a p h i t e i s u s u a l l y u s e d f o r t h e anode because i t i s r e s i s t a n t t o c o r r o s i o n and i t s e l e c t r i c a l r e s i s t a n c e i s low. S t a i n l e s s s t e e l i s t h e common c a t h o d e m a t e r i a l .

C o n t r o l o f S i l v e r C o n c e n t r a t i o n : The s o l u t i o n from which s i l v e r i s b e i n c r e c o v e r e d must c o n t a i n n o t l e s s t h a n 0 . 5 grams p e r l i t e r o f s i l v e r . I f t h e c o n c e n t r a t i o n i s l e s s t h a n t h i s , s i l v e r s u l f i d e w i l l fo rm i n t h e c e l l . S i l v e r s u l f i d e i s a b l a c k , f i n e l y d i v i d e d m a t e r i a 1 , w h i c h w i l l a ccumula t e on t h e c a t h o d e and f o u l i t . I f i t i s n o t con- t r o l l e d , t h e s u l f i d e w i l l p r e c i p i t a t e f rom t h e s o l u t i o n . I n a n a c i d s o l u t i o n , hydrogen s u l f i d e gas w i l l f o rm. The gas h a s an obnoxious odor ( r o t t o n e g g s ) and i s t o x i c . I f i t i s p r e s e n t , i t must b e removed by a d e q u a t e v e n t i l a t i o n .

r e c i r c u l a t i o n o f f i x e r can r e d u c e t h e c h l o r i n e demand d i s - c h a r g e f r o ~ i l 6 ~ h o t o g r a ~ h i c l a b by a s much a s 9 0 % , w h i l e r e d u c i n g che 20D5 f ~ c : : : o O - G C , : . a p p e a r zo ' : < . :::,: :.:!I-.- : ~ . ~ t h o d s t h a t a l l o w t h i s r e d u c t i o n . t o t a k e p l a c e . C~; , - : - . . LG~:S r c c i ~ c u l a t i o n of f i x e r s a l s o i n c r e a s e s i l v e r r e c o v e r y e f f i c i e n c y from a b o u t a 7 0 % maximum t o a 9 5 % maximum.

E l e c t r o l y t i c methods o f s i l v e r removal

B leach Recovery and Reuse

The b l e a c h i n g r e a c t i o n i n the p h o t o g r a p h i c p r o c e s s i s :

Overf low b l e a c h s o l u t i o n i s t h e n t r e a t e d s o as t o o x i d i z e f e r r o - c y a n i d e t o f e r r i c y a n i d e , t h e consumed h a l i d e i s added and t h e c h e m i c a l c o n c e n t r a t i o n s a d j u s t e d t o t h e d e s i r e d r e p l e n i s h e r t a n k l e v e l .

The m o s t common t e c h n i q u e o f b l e a c h r e g e n e r a t i o n i s t h e u s e of p o t a s s i u m p e r s u l f a t e . The r e a c t i o n i s :

P e r s u l f a t e r e g e n e r a t i o n i s w e l l documented.(38)

- - - - * 2 Fe(CN)6 - 3 + 2 so4

+ '2'8 -4

6 2 Fe (CN)

T h i s method has r e c e i v e d wide a t t e n t i o n b e c a u s e i t i s c h e a p , s i m p l e t o u s e , and does n o t r e q u i r e ma jo r c a p i t a l e x p e n d i t u r e s .

147

H O L C C V C ~ , t i ic a d d i t i o n o f s u l c a t e i n c r c a s e s t h e s p c c i f i c g r a v i t y 0 ; t h e 'oleacli,\vliicli u l t i n i a t c l y a f f e c t s b l e a c h i n g a c t i o n , A t t h a t p o i n t , t h e b l e a c h ' m u s t b c d i s c a r d e d i n l a r g e volumes, i m - p o s i n g a v e r y s e r i o u s p o l l u t i o n problem,

I i e g e n e r a t i o n , v i a o z o n a t i o n o r e l e c t r o l y s i s , p r o d u c e s no contam- i n a n t b y - p r o d u c t s and t h u s , t l i e r c would b e no need t o d i sGharge any b l e a c h . I t would b e c o n t i n u o u s l y r e c i r c u l a t e d . T h i s l a t e r iiietliod a l l o w s f o r 9 5 % r e d u c t i o n s o f complex c y a n i d e s d i s c h a r g e d t o t h e env i ronmen t .

O t h e r i n p l a n t r e c o v e r i e s have n o t been f o u n d s a t i s f a c t o r y f o r t h e p h o t o g r a p h i c p r o c e s s i n g i n d u s t r y , due t o p o t e n t i a l con tamin- a t i o n , q u a l i t y c o n t r o l , e t c . The c o n c e n t r a t i o n s o f t h e c h e m i c a l s found i n t h e w a s t e e f f l u e n t o f a t y p i c a l p h o t o f i n i s h i n g p l a n t a r e shown i n Table F - 1 , page 1 4 9 .

Tab le F - 2 l i s t s t h e amounts o f c h e m i c a l s , i n pounds p e r d a y , t h a t a r e d i s c h a r g e d by a t y p i c a l p h o t o f i n i s h e r p r o c e s s i n g Ektachrome, Kodacolor and E k t a c o l o r p r o d u c t s . A l s o l i s t e d i n T a b l e F - 2 , a r e t h e amounts of t h e same c h e m i c a l s t h a t a r e d i s c h a r g e d a f t e r t h e i n s t a l l a t i o n o f an i n - p l a n t t r e a t m e n t s y s t e m . The s y s t e m i n - c l u d e s e l e c t r o l y t i c s i l v e r r e c o v e r y , ozone r e g e n e r a t i o n o f f e r r i - c y a n i d e b l e a c h and ozone waste t reatment .

TABLE 17-1

C O N C E N T R A T I O N OF ClIEbl ICALS IN INUUSTRIAL WASTES

EFFLUENT AT A T Y P I C A L PHOTOFINISHING PLANT

Aminonium I o n Borax as B O 7 Bromide IoA C a r b o n a t e F e r r o c y a n a t e

N i t r a t e P h o s p h a t e S u l f a t e

. S u l f i t e S i l v e r

T h i o s u l f a t e T h i o c y a n a t e Z i n c A c e t a t e B e n z y i A l c o l h o

C o l o r D e v e l o p e r C D - 3 Formaldehyde Hydroquinone E l o n Hydroxylamine s u l f a t e

TOTAL MIXED EFFLUENT

(mg/ 1)

50 268 70

145 120

140 15 75

1 4 0 3

5 0 0 1 8

4 0 0 100

5 7 2 6 0

1 0 11 1 7

Sodium C i t r a t e 59

gpm ( p e a k l o a d ) 120

BOD5 ( a v e r a g e - n o m i x i n g ) 695 F l o w Rate l / m i n (peak l o a d ) 450

DILUTE WASH WATER O N L Y

(mg/l)

1 5 1 1 1

1

1 1

-

-

4 4

4 1

-

3 - - - 1

7 - 1 0 4 1 5 110

149

TABI,E F - 2

TABLU1,ATION OF C f I E M I C A L S REMOVED BY TR1':ATMI':N'T AND RENAINING IN EFFLUENTS AT

A TYPICAL P I I O T O F I N I S I I E R PROCESSING EK'I'AClIROME, KODACOLOR AND EKTACOLOR P R O D U C T S

Volume-gpm

Ammonium Ion-lh/day Borax Ion-lb/day Bromide Ion- lb/day Carbonate Ion-lb/day

m Ferrocyanide Ion-lb/day P

0

Nitrate Ion-lb/day Phosphate Ion-lb/day Sulfate Ion-lb/day Sulfite Ion-lb/day Silver Ion- lb/day

Thiosulfate Ion-lb/day Thiocyanate Ion-lb/day Zinc Ion-lb/day Acetate-lb/day Benzyl Alcohol-lb/day

Color Developer-lb/day Formaldehyde- lb/day Hydroqui O I I C - lb/day E l o n - l b / t ay Hydroxylamine sulfate-

1 b / d ay Sodium C i t r a t e - I b / d a y

BOD5 - lb/day

1 2 0

1 7 . 8 9 5 . 3 2 4 . 9 5 1 . 6 4 2 . 7

4 9 . 8 5 . 3

2 5 . 7 4 9 . 8 1.1

1 7 8 . 0 0 . 3 2 .8

1 4 2 . 0 3 5 . 6

2 0 . 3 9 2 . 5

3 . 5 3 . 9

6 . 0 3 3 . 8

247 .0

TOTAL % REblOVED (3) co N c E s 1' R A T li I ) I N D U S BY MAS'l'E AIC'I'fii< WASTE (1) TKEAlMIJN?' (2) WASFIISATER T K E AT :*I I: N 'I'

B C D

40 - -

60 9 5 1 5

none 9 5

1 5 1 5

none 1 0 0

9 5

80 1 5

1 5 40

none 80 10 1 0

none 1 0

5 5

- - - -

1 1 0

0 .2 0.1 0.3 0 . 9 0.09

0.6 0.06 0.3 - _ _ _ _ _ - - - _ - -

0 . 6 - - - - - - - - - - - - - _ 1.5 0.3

0.3 0.2s 0 -05 0 .os

0.1 0 - 4

2 - 0

1 0

6 . 9 . 4 . 7 20 .9 5 0 . 7

2 . 1

4 1 . 7 4 . 5

2 6 . 4

0 . 2

43.9

- - - - -

0 . ? 5 _ _ _ _ _ - 1 1 9 . 5

2 1 . 1

2 0 . 0 1 5 . 2 5

3 . 0 5 3 . 4 5

5 . 9 3 0 . 0

1 0 9 . 1

TABLE F-2

(con t inued)

1 Based on average processor operation o f 6 hrs/day

2. A: Electrolytic Silver Recovery with Fixer Recirculation

B: Ferricyanide Bleach Regeneration with Ozone or by Electrol;. c

C: Chemical Destruction with Strong Oxidant such as Ozone Chlorine, Peroxide or Permanganate.

D: Total of A , B G C

3 As percent of total amount present in industrial waste

SICLECTED W A T E R 1. Report No. K E S O U R C E S A B S T R A C T S I N P U T T R A N S A C T I O N FORM

3 Acce\sion Nc 2.

vv

H e n d r i c k s o n , Thomas N . D a i a n a u l t . Louis G .

9. Oraani za t ion

17a. D e s c r i p t o r s

* A n a l y t i c a l T e c h n i q u e s , *Chemical P r e c i p i t a t i o n , * C h l o r i n a t i o n , * O x i d a t i o n , *Ozone, * E l e c t r o l y s i s , c h l o r i n e , c o a g u l a t i o n , Chemical Waste , L a b o r a t o r y T e s t s , E l e c t r o C h e m i s t r y , F l o c c u l a t i o n , Heavy M e t a l s , T o x i c i t y , C o s t s , Water T r e a t m e n t , B iochemica l Oxygen Demand, Chemical

P7PX%t ;eEmand - * P h o t o f i n i s h i n g Wastes, " F e r r i c y a n i d e , Chemical Recovery , "Complex Cyanides , Waste Recycle .

10. P r o j e c t N o .

E P A , 1 2 1 2 0 E R F

17c. C O W R R Field di Group

18. Ava i lab i l i t y 19. Security Class. 21 . N o . of Send T o : Pages I (Repor t )

Berkey F i l m P r o c e s s i n g o f N . E . 2 6 0 Lunenburg S t r e e t

WATER RESOURCES SCIENTIFIC I N F O R M A T l O h CENTER 20. Security Class. 22. Price DEPARTMENT T H E

(Pagel I WASHINGTON D C 2n74n

1 1 . C o n t r a c t l G r a n t N o