Egyptian Journal of Aquatic Research (2017) 43, 1–9

HO ST E D BYNational Institute of Oceanography and Fisheries

Egyptian Journal of Aquatic Research

http://ees.elsevier.com/ejarwww.sciencedirect.com

FULL LENGTH ARTICLE

Advanced oxidation processes of Mordant Violet 40

dye in freshwater and seawater

* Corresponding author.E-mail addresses: ahmedmoustafaelnemr@yahoo.com, ahmed.m.

elnemr@gmail.com (A. El Nemr).

Peer review under responsibility of National Institute of Oceanography

and Fisheries.

http://dx.doi.org/10.1016/j.ejar.2016.09.0041687-4285 � 2016 National Institute of Oceanography and Fisheries. Hosting by Elsevier B.V.This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Mohamed A. Hassaan a, Ahmed El Nemr a,*, Fedekar F. Madkour b

aEnvironmental Division, National Institute of Oceanography and Fisheries, Kayet Bey, El-Anfoushy, Alexandria, EgyptbMarine Science Department, Faculty of Science – Port Said University, Port Said, Egypt

Received 23 August 2016; revised 10 September 2016; accepted 22 September 2016Available online 24 November 2016

KEYWORDS

Ozone;

Ultraviolet;

Mordant Violet 40 dye;

Advanced oxidation;

Decolorization

Abstract This paper examines the possibility of applying ozone (O3) and O3 combined with ultra-

violet (UV) to degrade the content of synthetic wastewater Mordant Violet 40 dye (MV-40). The

experimental parameters included pH, initial dye concentration and time of reaction; all were

assessed in a batch reactor to achieve the optimum operating circumstances. The results obtained

showed that the pH and initial MV-40 dye concentration controlled the decolorization process.

The maximum decolorization of MV-40 dye solution was obtained at pH 9. More than 98% of

color removal was obtained within 20 min for both UV assisted O3 and individual O3 treatment

of 100 ppm dye concentration. Kinetic analyses showed that the decolorization of MV-40 dye fol-

lowed the second-order kinetics. The degree of decolorization of MV-40 dye solution was indirectly

proportional to the initial dye concentration. Gas Chromatography Mass Spectrum analysis of

treated synthetic dye solution was performed at the end of the pre-treatment time to the final degra-

dation products of MV-40 dye. The obtained results explained that the advanced oxidation pro-

cesses enhanced the biodegradability and lowered the zooplankton toxicity of the treated MV-40

dye solution.� 2016 National Institute of Oceanography and Fisheries. Hosting by Elsevier B.V. This is an open access

article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Introduction

The industry of textile has been playing a significant role inrecent times, as it consumes a massive quantity of dyes. The

quantity and quality of the resulting wastewaters from textileindustries have been a matter of concern for governmentsand public (El Nemr, 2012a, 2012b). One of the biggest indus-

tries in Egypt is the textile industry in respect to the number oflabor, the export prices and the local production cost. Thisindustry has been considered a significant provider of environ-mental pollution, especially in wet processes where harmful

chemicals are used. The Egyptian textile industry consists of31 public sector firms and about 3000 private sectors and jointventure facilities (EPAP/EEAA, 2003).

The occurrence of organic contaminants in the hydrospheresuch as dyes, pesticides, and surfactants (El Nemr et al., 2003,2004, 2008, 2012, 2015) causes particular concerns in both

marine and freshwater environments due to the possible car-cinogenic nature and non-biodegradability of most of thesecompounds (El Sikaily et al., 2003, 2011; Khaled et al., 2003;

OHO

HOOC COOH

COOH

OH

Figure 1 Chemical structure of Mordant Violet 40 dye (Molec-

ular Formula: C22H11Na3O9) (Molecular Weight: 488.29). Soluble

in water for red, soluble in ethanol for titian. In concentrated

sulfuric acid for blue purple, red after diluted solution, and then a

brick red precipitation. kMax = 510 nm; C.I. 14,745.

2 M.A. Hassaan et al.

Amini et al., 2011; Mozia et al., 2008; Atchariyawut et al.,2009; Mahmoodi and Arami, 2010). In the effluent of the tex-tile industry, the presence of color is due to using large quan-

tities of dyestuffs in the dyeing processor (Oneill et al., 1999; ElNemr et al., 2014). Advanced Oxidation Processes (AOPs) arethe processes which produce a powerful non-selective hydroxyl

radicals in adequate quantities to oxidize most of the organicchemicals existing in the wastewater (Gogate and Pandit,2004; EPA, 1998). Hydroxyl radicals (_OH) have the highest

oxidation potential (E0: 2.8 eV) after the strongest oxidant flu-orine radical (E0: 3.06 eV), which cannot be applied in theAOP of textile wastewater due to its high toxicity. Therefore,production of OH radicals using AOPs has drawn the atten-

tion of the environmental scientists and technology developersworking in the wastewater treatment field. Ozone is extensivelyapplied as an agent of strong oxidizing effect to treat both

water and wastewater (Steahlin and Hoigne, 1982). Ozoneattacks pollutants in direct via attack the ozone onto theorganic compound to form manly hydroxyl and carboxylic

groups and indirect radical chain reactions via attach theozone onto water to form hydroxyl radicals which then attackthe organic compounds to form manly similar results as direct

attack (Arslan and Balcioglu, 2000). Eq. (1) shows the reactionmechanisms of ozone at high levels of pH.

3O3 þH2O ! 2�OHþ 4O2 ð1ÞHydroxyl radicals can be created by O3 in the presence of

UV radiation as shown in Scheme 1.

Due to the fact that the O3/UV process does not have thesame limits of the H2O2/UV process, low pressure mercuryUV lamps are the used source of UV irradiation in this pro-

cess. Different variables affect the efficiency of the AOP systemsuch as temperature, pH, scavengers, turbidity, UV intensity,and pollutant type(s) (EPA, 1998; Azbar et al., 2005). The pur-

pose of this work is to test the O3 and O3/UV processes fortreatment of the Mordant Violet 40 dye in a wastewater andseawater, and to study the effect of different parameters on

the dye degradation rate.

Materials and methods

Mordant Violet 40 dye was obtained from ISMA dye companyKafer Eldawar, Egypt, 75% of the dye’s content was usedwithout further purification. MV-40 dye chemical structure isshown in Fig. 1. A stock solution of 1000 mg/l of MV-40

dye was prepared using double distilled water. Other workingaqueous solutions of MV-40 dye (100, 200, 300, 400 and500 mg/l), were obtained from the stock solution by dilution

in double distilled water to the required concentration. MV-40 dye concentrations were determined by comparison withstandard solutions using UV–VIS spectrophotometer (Analyt-

icjena Spekol 1300 UV VIS Spectrophotometer, Model No45600-02, Cole Parmer Instrument Co., USA) for absorbance

Scheme 1 Reaction of O3 and water in the presence of UV.

measurements at kmax 510 nm (retrieved from Dye, World DyeVariety, 2016). The color removal rate of MV-40 dye wasdetermined by Eq. (2).

Color removal efficiency% ¼ A0 � At

A0

� 100 ð2Þ

where A0 and At are the initial and the measured absorbance ofthe samples at different time intervals.

Ozonation was handled in a 200 ml cylindrical glass reactoras shown in Fig. 2. All links from the Ozonator to the reactionvessels were made of Teflon tubes. Because of low reactor

capacity, 200 ml of freshly prepared MV-40 dye was employedfor every run time. Fig. 2 shows the ozone generator Model: N1668A power: 18 W Vol AC 220V/50HZ was used to produce

ozone with a flow of 500 mg of O3/h. The ozone that left thereactor was caught into two-sequential bubblers filled with(KI) (2%) solution. Also, other tests were performed usingthe AOPs (O3/UV), therefore Horizontal Clean Bench/Lami-

nar Floe Cabinet (Bw-LFH1300) with UV low pressure mer-cury lamp 254 nm with 30 W Power was used.

The chemical oxygen demand (COD) was determined

according to the procedure stated in (APHA, 2005). TheCOD was calculated for both untreated and treated MV-40dye at concentration of 500 mg/l.

Influence of the pH was studied via adjusting the wastewa-ter and seawater to different initial pH values, ranging from 3to 11, while using 1 M H2SO4 or 1 M NaOH before starting

ozonation or UV enhanced O3 processes. The pH measure-ments were carried out using JENCO Electronics, LTD pHmeter (Model: 6173, Serial No.: JC 05345).

The separation of the intermediates in addition to the end

by-products in the advanced oxidation of treated wastewatersamples, was done in an Agilent Technologies 7890A GCinstrument equipped with mass detector (5975C MSD) and

HP5 column (30 m � 0.25 mm i.d., 0.25_mm film thickness)using benzene for the extraction (USEPA, 1996). The temper-ature of the injector was 280 �C (splitless), with an initial oven

temperature of 80 �C, a 63 min isotherm and a final oven tem-perature of 300 �C. The carrier gas was He, with a column flowof 1.5 ml/min.

Toxicity assay

To evaluate the toxicity of the MV 40 dye on the zooplankton,Rotifer Brachionus plicatilis toxicity experiments were tested

Figure 2 Design of the ozonation experiment.

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30

pH 3pH 5pH 7pH 9

pH 11

Colo

r Rem

oval

%

Time (min.)

Figure 3 Color reduction of the Mordant Violet 40 dye versus

contact time at different pH (3, 5, 7, 9 and 11) (dye concentration:

100 mg/l, O3: 500 mg/h and 200 ml treated volume).

91

92

92

93

93

94

94

95

95

1 3 5 7 9 11

Col

or R

emov

al %

afte

r 10

min

.

pH

Figure 4 Effect of different pH (3, 5, 7, 9 and 11) on

decolorization of Mordant Violet 40 dye after 10 min (dye

concentration: 100 mg/l, O3: 500 mg/h and 200 ml treated

volume).

Advanced oxidation processes of Mordant Violet 40 dye 3

on both untreated wastewater and after the 25-min UVassisted ozonation treated solutions at the complete colorremoval. The procedures for the toxicity bioassay of rotifer

generally follow the recommendations of (SMWW, 1985;USEPA, 1985). Test animals were obtained by hatching Bra-chionus plicatilis cysts to eliminate the need for stock cultures

and to greatly reduce the test variability. That is because theanimals that had hatched from cysts were of similar age, geno-type and physiological condition. The controlled cyst hatchingwas achieved by transferring them to warmer temperature,

lower salinity and more light. Hatching began and proceededrapidly after 23 h at 25 �C and 15‰ salinity. In 28 h, about90% of the cysts had hatched (Terry and Guido, 1989). Toxi-

city assay was done using neonates of Rotifer Brachionus pli-catilis. 40 ml of MV 40 dye with concentration (500 mg/l)had completed to 200 ml seawater, each ml of seawater con-

tained 20 neonates of Rotifer Brachionus plicatilis for treatedand untreated samples. The control wells contained the samevolume of normal seawater. The number of live and dead neo-

nates in every well was calculated by an inverted trinocularmicroscope (Nikon Eclipse E200) at different time intervalsof 0, 15, 30, 45 and 60 min.

Results and discussion

Effect of pH value

Ozone decompose to hydroxyl radicals (�OH) under alkalineconditions then react with the target organic contaminant.

On the other hand, under acidic conditions, ozone mainly reactdirectly as ozone radical with organic compounds (Wang et al.,2008). Fig. 3 illustrates the color removal of MV-40 dye in dif-

ferent pH values. Fig. 4 shows that the color of MV-40 dye wasreduced from the initial concentration of 100 ppm to below8 ppm within the first 10 min only, after ozone was provided

at 500 mg/h and pH 9. Fig. 5 shows the change in the initialpH of MV-40 dye concentration of 500 ppm from 9 to 8 atthe complete color removal stage. The highest removal ratefor MV-40 dye occurred under a caustic condition (pH 9).

Ozone controlled the process of oxidation at a lower pHwhereas the hydroxyl radical indicated more considerableinfluence at a higher pH (Chu and Ma, 2000). As a result of

the sluggish decay rate (i.e., O3 reaction with less plentifulOH�) at lower pH, O3 would build up in the liquid phase toan elevated concentration (i.e., higher O3 saturation concentra-

tion at acidic pH). Moreover, as a result of the influence thathappened due to extra massive reactions of O3 with OH� at

an elevated pH, stable state concentration of O3 in the waterdecreased while more hydroxyl radicals (�OH) were generatedat elevated pH (Chu and Ma, 2000). The above mentionedrelationships influenced the color removal in the liquid phase

below in the two following ways: (1) O3 molecule controlsthe process of oxidation at lower pH state and (2) hydroxyl

7.5

8.5

9.5

10.5

11.5

0 15 30 45 60 75 90 105 120

pH

Time (min.)

O3

O3+UV

Figure 5 pH monitoring during ozonation and advanced

oxidation processes (O3: 500 mg/h, treated volume: 200 ml, initial

solution pH 9 and 500 mg/l dye concentration).

0102030405060708090100

0 20 40 60 80 100 120

100mg/L200mg/L300mg/L400mg/L500mg/L

Col

or R

emov

al %

Time (min)

Figure 6 Effect of ozone on Mordant Violet 40 dye concentra-

tions (100, 200, 300, 400 and 500 mg/l) versus time (O3 concen-

tration: 500 mg/h, treated volume: 200 ml and initial solution pH

9).

0102030405060708090100

0 20 40 60 80 100

100mg/L

200mg/L

300mg/L

400mg/L

500mg/LC

olor

Rem

oval

%

Time (min)

Figure 7 Effect UV assisted ozone on different Mordant Violet

40 dye (100, 200, 300, 400 and 500 mg/l) versus time, ozonation

(O3 concentration: 500 mg/h, treated volume: 200 ml and initial

solution pH 9).

4 M.A. Hassaan et al.

radical (�OH) controls the oxidation process at higher pHstates. Hydroxyl radicals (�OH) have higher oxidizing potentialand are also less selective than molecular ozone O3 when it

comes to attacking the chromospheres of dye, leading to adecrease in the rate of decolorization and an increase in therate of mineralization at high pH values (Oguz et al., 2006;

Beltran, 2004; Swaminathan et al., 2005). Thus, the pH ofthe solution and the structure of the dye play an important rolein the ozonation process. They can also affect the rate of decol-

orization by the oxidation of hydroxyl radical or ozone. It isalso worth mentioning that the pH of the solution droppedfrom the initial solution (pH 9 at t = 0 min) to about 8.18 after1 h of ozonation. Later, the decrease of pH slowly continued

until a steady state was reached. Even though, the pH valuehad dropped, it was still in the alkaline state; this can be seenin the case of Mordant Violet 40 dye where maximum color

removal happened at pH 9. Outcomes from this work revealthat suitable pH regulation might be mandatory after the mainoxidation mechanisms are verified.

Effect of initial dye concentration

It is crucial to investigate how the concentration of initial dye

influences the removal of color. Thus, the influence of MV 40(100–500 mg/l initial dye concentrations) on color reductionwas examined. The effect of MV-40 dye initial concentrationon decolorization efficiency is shown in Figs. 6 and 7. The

decolorization of the MV-40 dye by UV enhanced ozonationis more effective than ozonation alone, this was found to bein agreement with what was mentioned by Peternel et al.

(2006).Fig. 6 shows the effectiveness of MV-40’s color reduction in

different initial concentration values. The removal efficiency of

MV 40 dye initial concentration values of 100, 200, 300, 400and 500 mg/l in the first 25 min was 98.5, 97.9, 97.1, 96.6and 94.9%, respectively for O3 only. Although the removalefficiency for the concentration of 300 ppm was the same for

the first 25 min, the 200 ppm concentrations took about 15more minutes to reach the same removal percentage for200 ppm (99.2%).

By increasing the dye concentration in AOPs, numerousintermediates arose. That was after the parent dye’s degrada-

tion which interfered with the oxidation process. Such suppres-sion would have been more noticeable in the existence of anelevated amount of degradation intermediates that had arisen

after the increase in dye concentration (Song et al., 2008).Therefore, the time required for complete color removalshould be longer for higher initial dye concentrations. Fig. 7shows the color reduction effectiveness for concentration val-

ues of 100, 200, 300, 400 and 500 mg/l in the first 25 min; theywere 98.5, 98.3, 98.1, 97.3 and 96.9% respectively, for UVassisted O3. The color removal efficiency processes were

reduced as the initial dye concentration increased because theof the stable ozone dosage.

It is seen from Figs. 4 and 5 that when the dye concentra-

tion increased the color removal rate decreased leading toslower creation of complete decolorization, which attributedto the ratio of dye molecules to ozone radicals in the solutiondecreased with the increase of the dye concentration (Oguz

et al., 2006). As mentioned by Sevimli and Kinaci (2002), anincrease in the initial dye concentration would cause moreozone to be destroyed.

From Figs. 6 and 7 it is shown that the time needed forcomplete color removal of MV-40 dye decreased by 5, 20, 15and 15 min for different dye concentration values of 200,

300, 400 and 500 ppm, respectively, in the case of UV/O3 pro-cesses rather than O3 alone. This shows better performance indye degradation by UV/O3 process in comparison to ozone

Advanced oxidation processes of Mordant Violet 40 dye 5

alone. UV enhanced O3, in comparison to ozone alone, canproduce more hydroxyl radicals which are more efficient formineralization. This also shows that ozone stability declines

by raising the pH, causing the production of secondary oxi-dants. In acidic pH, the ozone is available as molecular O3,while in basic pH it decomposes into hydroxyl radical consid-

ered as the most important secondary oxidants. The oxidationpotential of ozone decreased in alkaline solutions which alsoindicated higher decomposition and lower solubility of ozone

(Yasar et al., 2007).

Chemical oxygen demand (COD) removal

After 1 h and 20 min of AOPs (after complete color removal)more than 72% of the initial COD was eliminated for500 ppm. Similarly to what was stated before (Zhao et al.,2004), the ozonation of dyes commonly produces little organic

molecular fragments (e.g. ketones, epoxides, aldehydes, etc.)that may lead to a remaining COD. Such COD developingfrom those few newly produced compounds, can be later

reduced by biological treatment methods if necessary (Linand Chi, 1993).

Kinetic of Mordant Violet 40 dye

The kinetic study of ozonation system plays an essential role inevaluating the effectiveness of treating dye polluted wastewa-ter. The direct reaction of ozone is supposed to be first order

in regards to dye and ozone, respectively. If the ozone concen-tration reaches a stationary phase, the rate of oxidation fol-lows a second-order kinetics. The kinetics of the ozonation

of MV 40 dye was evaluated by plotting 1/Ct - 1/C0 values ver-sus reaction time (Eq. (3)):

1

Ct

� 1

C0

¼ kdt ð3Þ

where Ct is the concentration of MV-40 dye at the reactiontimes (t), C0 is the MV-40 dye initial concentration and kd isthe reaction rate constant of the second-order.

Figs. 8 and 9 illustrate the removal of dye concentrationversus time; the latter was relatively quick in the first 5 minof both ozonation and UV assisted ozonation; then, dye fadingspeed became slower. In this work, it was noticed that the sec-

ond order rate constant (kd) decreased when the initial MV-40

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 20 40 60 80 100 120

100mg/L200mg/L300mg/L400mg/L500mg/L

1/[C

t]−1/

[C0]

Time (min)

Figure 8 Kinetics of the Mordant Violet 40 ozonation ([O3]

= 500 mg/h, treated volume = 200 ml, initial solution pH 9).

dye concentration increased in both the AOPs and ozonationprocess (Figs. 8 and 9). In this study, the reaction order ratewas found to be different than that reported by (Wu and

Wang, 2001), who indicated that pseudo-first-order behaviorswere obtained through ozonation of azo-dyes. Also, the MV-40 dye decolorization by O3 and UV assisted O3, followed

apparent pseudo-second-order kinetics; that disagreed withother works (Kusvuran et al., 2011; Zhang et al., 2006). A ser-ies of kd are shown in Table 1, when kd values ranged from

0.0242 to 0.0034 mol�1 min�1 for O3 only, which were lowerthan those reported for O3 + UV processes (ranged from0.0259 to 0.0044 mol�1 min�1).

Identification of the intermediates byproducts of MV 40 dyeduring the AOP

It is desirable that the ozonation of the decomposed final prod-

ucts be safe, but the intermediates and end products after theozonation of dyes would have poisonous influences(Vanhulle et al., 2008; Selcuk et al., 2006; Shang et al.,

2002). Therefore, identification and/or ecotoxicological assess-ment of such intermediates and final products have to be doneto prevent problems with successive biological treatment. As

stated before (Kralicek, 1995; Pielesz et al., 2002; Alvareset al., 2001), a lot of earlier data indicated that the intermedi-ates and end products of ozonation depend on the chemicalstructure of the treated dye and the ozonation circumstances.

Fig. 10 shows the GC–MS chromatograms of UV enhancedozonation textile wastewater (pH 9) after 25 and 55 min. FromFig. 10 it is obvious that AOPs considerably lowered the sub-

stances of the remaining undecomposed organic compounds.Preliminary analysis of the ozonated synthetic wastewater

showed the peak at retention time of 13.478 min. It was iden-

tified as being tetradecamethyl cycloheptasiloxane. Otherpeaks at retention times of 16.296 and 18.860 min were hex-adecamethyl cycloheptasiloxane and 2-Hexadecanol, respec-

tively. Presence of butyl octyl ester of 1,2-benzenedicarboxylic acid was also shown at (retention time20.142 min), as well as the absorption peaks of dibutyl phtha-late (retention time 21.933 min) and diisooctyl phthalate

(retention time 31.670 min) (Fig. 10a). Certain aromatic com-pounds can react quite slowly during the ozonation processand may need more treatment time to be oxidized (Cleder

et al., 2010). During the experimental circumstances operated

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 20 40 60 80 100 120

100mg/L200mg/L300mg/L400mg/L500mg/L

1/[C

t]−1/

[C0]

Time (min)

Figure 9 Kinetics of the Mordant Violet 40 dye using UV

assisted ozonation ([O3] = 500 mg/h, treated volume = 200 ml,

initial solution pH 9).

Table 1 Second order constant (kd) and initial concentration of MV-40 dye in AOP comparison to ozonation alone processes (pH 9,

UV lamp 254 nm, power = 30 W, O3 = 500 mg/h).

Initial MV-40 (mg/l) kd � 10�3 (mole�1 min�1) UV+ O3 R2 kd � 10�3 (mole�1 min�1) O3 R2

100 25.9 0.914 24.2 0.958

200 12.4 0.928 11.0 0.924

300 10.0 0.900 6.3 0.866

400 7.4 0.955 5.6 0.823

500 4.4 0.906 3.4 0.814

Figure 10 GC–MS chromatograms of the advanced oxidation processes for synthetic wastewater (pH 9) (a) after 25 min and (b) after

55 min.

6 M.A. Hassaan et al.

in this work, we extended the time for ozonation for another30 min, and we noticed that the ozonation was very useful in

the degradation of some compounds; we could also only seethe absorption peaks of dibutyl phthalate (retention time21.933 min) and diisooctyl phthalate (retention time

31.670 min) (Fig. 10b).We noticed that most of the fragmentation of MV-40 dye

degradation (phenol or other aromatic amine) almost disap-

peared and that the concentration of the alkene and phthalatecompounds appeared in very low concentrations in ng/l. It iswell-defined that ozonation notably reduced the contents ofthe organic synthetic wastewater extracts.

Toxicity test

Bioassay on rotifer B. plicatilis

The toxicity rates were evaluated by examining the mortalitynumbers of Rotifer B. plicatilis. The mortality rates in the

ozone treated 100 mg/l of MV-40 dye, were close to 0, 0, 2, 4and 5% after 0, 15, 30, 45 and 60 min, respectively (Fig. 11),

while the raw dye of similar concentrations exhibited 0, 5, 8,15 and 30, respectively. It is also worth mentioning that thetreated and untreated samples were left for 24 h and the mor-

tality percents were still at the same levels of 30% and 5% foruntreated and treated samples, respectively. From Fig. 11, onecan also see there had been no mortality for control samples at

the first hour. The textile industries use various dye groups,70% of those dyes are azo dyes that were also identified tobe noxious in nature (Ogunjobi et al., 2012). After completecolor removal, the textile effluent noxiousness generated was

also decreased (Furlan et al., 2010). The toxicity test showsthat the mortality levels of untreated wastewater were morethan those of the treated ones, which indicate that the treated

wastewater was less poisonous to the marine aquatic organ-isms and could be released with less harm to the marine ecosys-tem (Khadhraoui et al., 2009). The mortality test made an

0

2

4

6

8

10

12

14

16

0m 15m 30m 45m 60m

TOXICITY

Untreated

Treated

Control

Rot

ifer

Mor

talit

y %

Exposure Time (min)

Figure 11 Toxicity of the raw and ozonated solutions at

different exposure time ([Dye] = 100 mg/l, [O3] = 500 mg/h,

treated volume = 200 ml, ozonation time = 25 min).

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70

O3

100mg/L200mg/L300mg/L400mg/L500mg/L

Colo

r Rem

oval

%

Time (min)

Advanced oxidation processes of Mordant Violet 40 dye 7

obvious revelation that the AOPs had a positive outcome onthe zooplankton toxicity of the raw Mordant Violet 40 dye

solution.

Application of ozone and UV assisted ozone on seawater

The seawater sample was taken in the front of Kayet Bey Cas-

tle in Alexandria, Egypt and some physical and chemicalparameters were measured as shown in Table 2. Stock of1000 mg/l of MV-40 dye was prepared using seawater and

other working aqueous solutions (100, 200, 300, 400 and500 mg/l) of MV-40 dye, which was obtained from the freshprepared stock solution by dilution with seawater to the

required concentration. The experiment ran under the sameconditions stated in Table 2 to stimulate the discharge ofindustrial dye wastewaters in coastal areas.

Effect of the initial dye concentration

The effect of initial MV-40 dye (with different concentrationsof 100–500 mg/l) on the decolorization was investigated. The

effect of MV-40 dye initial concentration on decolorization

Table 2 Physical and chemical parameters of collected

seawater.

Temp. 27.5 �CpH 7.75

EC 60.9 ms/cm

TSM 0.0152

DO 1.14 mg/l

Salinity 38.7

Nutrients

PO4 0.096 lg/l (PO4-P)

NO2 2.1 lg/l (NO2-N)

Heavy metals ppm

Cd 0.10

Zn 0.91

Cu 1.31

Fe 2.56

Pb 3.67

Mn 0.85

Ni 1.72

efficiency is shown in Figs. 12 and 13. Fig. 12 shows the decol-orization efficiency of MV-40 dye at different initial dye con-centration values. The percentage of decolorization efficiency

for initial dye concentration values of 100, 200, 300, 400 and500 mg/l within the first 15 min were 99.9, 96.7, 96.5, 94.2and 95.1%, respectively, for O3 only. Although the removal

efficiency for 500 mg/l concentration was almost the same as400 mg/l concentration in the first 15 min, it still took about5 more minutes to reach the same removal percentage for

400 mg/l (99.8%).Fig. 13 shows the percentage of decolorization efficiency for

initial dye concentration values of 100, 200, 300, 400 and500 mg/l in first 20 min to be 99.9, 93.4, 88.6, 89.6 and

86.6%, respectively, for UV assisted O3 treatment. Also, it isworth mentioning that from Figs. 8 and 9 we can deduce thatthe same took place in fresh water treatment and that by

increasing the initial dye concentration, the color removal ratepercentage decreased and the complete removal of colorrequired more time to occur.

Figs. 12 and 13 clearly show that ozone was more effectivethan UV assisted O3 for (100, 200, 300, 400 and 500 mg/l) con-centrations. This can be explained by considering the scaveng-

ing effects of Cl� ions on the hydroxyl radicals (Muthukumarand SelvaKumar, 2005).

Figure 12 Effect of ozone one different Mordant Violet 40 dye

concentrations (100, 200, 300, 400 and 500 mg/l) versus time, ([O3]

= 500 mg/h, treated volume = 200 ml, initial solution pH 7.75).

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120

O3 + UV

100mg/L200mg/L300mg/L400mg/L500mg/L

Time (min)

Colo

r Rem

oval

%

Figure 13 Effect UV assisted ozone on different Mordant Violet

40 dye concentrations (100, 200, 300, 400 and 500 mg/l) versus

time, ozonation ([O3] = 500 mg/h, treated volume = 200 ml, ini-

tial solution pH 7.75).

8 M.A. Hassaan et al.

Also another important reason is the pH of the reaction,which is the seawater pH 7.75. This value is not high enoughto stimulate the decomposition of O3 or produce hydroxyl rad-

ical, especially when compared to fresh water treatment at pH11 and when the UV assisted O3 was higher than O3 alone. It isalso known that stability of ozone is affected by the presence of

scavenger ions, pH and temperature Mallevialle (1982).It could also be as mentioned that in freshwater treatment,

the appropriate pH is required to determine the major oxida-

tion mechanisms. In this study, the excrement which runsunder slightly alkaline pH and is not high enough to makehydroxyl radicals, dominates the oxidation process. Therequired time for complete color removal is affected by the

salts present in the dye solution (Muthukumar andSelvaKumar, 2005). As the salt content gets higher (38.7‰),the time required for complete color removal becomes longer.

This could be a different reaction pathway depending on theUV assisted O3 reaction, that may lead to more resistant inter-mediate products to further oxidation. It is worth noting that

Cl� ion consumed (_OH) and O3 via serial groups of chemicalreactions as mentioned by Mallevialle (1982). Also, we noticedthat the time needed to complete decolorization for MV-40 dye

in seawater in the case of O3 + UV, is higher than that infreshwater and these results were found to be in agreementwith literature (Khadhraoui et al., 2009).

Conclusion

This work was to study the efficiency of using ozone and ozonecombined with UV for color removal and detoxification of an

aqueous solution of Mordant Violet 40 dye. The major conclu-sions derived from the present work are as follows: ozonetreatment proved to be very effective for complete color

removal but provided only partial reduction of COD whichis in agreement with many reported work as mentioned abovein the results and discussion section. The oxidation of the MV-

40 dye in freshwater followed the second-order kinetics andcolor removal efficiency was higher in case of UV and O3 com-bination compared to ozone alone and it attributed to the pro-

duction of more hydroxyl radicals, which were more efficientfor mineralization. The application of the same methods forthe treatment of MV-40 dye solution in seawater was studiedand gave mainly similar results obtained for fresh water. Fur-

thermore, GC–MS analysis for identifying the ozonation by-products as well as evaluating the degradation of the treatedaqueous solutions, showed no toxic compounds. The obtained

results also revealed that advanced oxidation processesreduced the zooplankton toxicity of the raw solution.

Conflict of interest

The authors declared that there is no conflict of interest.

References

Alvares, A.B.C., Diaper, C., Parsons, S.A., 2001. Partial oxidation by

ozone to remove recalcitrance from wastewaters a review. Environ.

Technol. 22, 409–427.

Amini, M., Arami, M., Mahmoodi, N.M., Akbari, A., 2011. Dye

removal from colored textile wastewater using acrylic grafted

nanomembrane. Desalination 267, 107–113.

APHA, 2005. Standard Methods for the Examination of Water and

Wastewater. American Public Health Association/American

Water Works Association/Water Environment Federation, Wash-

ington, DC, USA.

Arslan, I., Balcioglu, I.A., 2000. Effect of common reactive dye

auxiliaries on the ozonation of dye house effluents containing vinyl

sulphone and aminochlorotriazine dyes. Desalination 130, 61–71.

Atchariyawut, S., Phattaranawik, J., Leiknes, T., Jiraratananon, R.,

2009. Application of ozonation membrane contacting system for

dye wastewater treatment. Sep. Purif. Technol. 66, 153–158.

Azbar, N., Kestioglu, K., Yonar, T., 2005. Application of Advanced

Oxidation Processes (AOPs) to wastewater treatment. Case studies:

decolourization of textile effluents, detoxification of olive mill

effluent, treatment of domestic wastewater. In: A.R. Burk (Ed.),

Water Pollution: New Research, Nova Science Publishers, New

York, pp. 99–118, ISBN-1-59454-393-3.

Beltran, F. J., 2004. Ozone reaction kinetics for water and wastewater

systems, Levis Pub., imprint of CRC Press LLC, Florida.

Chu, W., Ma, C.W., 2000. Quantitative prediction of direct and

indirect dye ozonation kinetics. Water Res. 34, 3153–3160.

Cleder, A.S., Simionatto, E.L., Bertoli, S.L., Alberto, W.J., Claudemir,

M.R., 2010. Use of ozone in a pilot-scale plant for textile

wastewater pre-treatment: physico-chemical efficiency, degradation

by-products identification and environmental toxicity of treated

wastewater. J. Hazard. Mater. 175, 235–240.

Dye, World Dye Variety, 2016. <http://www.worlddyevari-

ety.com/mordant-dyes/mordant-violet-40.html> (accessed

2016.07.31).

El Nemr, A., Khaled, A., Abdelwahab, O., El Sikaily, A., 2008. Direct

Yellow 12 by activated carbon developed from Orange Peel.

Desalination 238, 210–232.

El Nemr, A., 2012a. Textiles: Types, Uses and Production Methods,

Nova Science Publishers, Inc., Hauppauge New York. Hard Cover,

621 pages [ISBN: 978-1-62100-239-0], e-book [ISBN: 978-1-62100-

284-0].

El Nemr, A., 2012b. Non-Conventional Textile Waste Water Treat-

ment, Nova Science Publishers, Inc., Hauppauge New York, 267

pages. [Hard cover ISBN: 978-1-62100-079-2, e-book ISBN: 978-1-

62100-228-4].

El Nemr, A., El Sadaawy, M.M., Khaled, A., El Sikaily, A., 2014.

Adsorption of the anionic dye Direct Red 23 onto new activated

carbons developed from Cynara cardunculus: kinetics, equilibrium

and thermodynamics. Blue Biotechnol. J. 3 (1), 121–142.

El Nemr, A., El Sikaily, A., Khaled, A., Abdelwahab, O., 2015.

Removal of toxic chromium from aqueous solution, wastewater

and saline water by marine red alga Pterocladia capillacea and its

activated carbon. Arab. J. Chem. 8, 105–117.

El Nemr, A., El-Sikaily, A., Khaled, A., Said, T.O., Abd-Alla, A.M.

A., 2004. Determination of hydrocarbons in mussels from the

Egyptian Red Sea coast. Environ. Monit. Assess. 96 (1–3), 251–

261.

El Nemr, A., Khaled, A., Moneer, A.A., El Sikaily, A., 2012. Risk

probability due to heavy metals in bivalve from Egyptian

Mediterranean coast. Egypt. J. Aquat. Res. 38 (2), 67–75.

El Nemr, A., Said, T.O., Khaled, A., El Sikaily, A., Abd-Allah, A.M.

A., 2003. Polychlorinated biphenyls and chlorinated pesticides in

mussels collected from the Egyptian Mediterranean Coast. Bull.

Environ. Contam. Toxicol. 71 (2), 0290–0297.

El Sikaily, A., El Nemr, A., Khaled, A., 2011. Copper sorption onto

dried red alga Pterocladia capillacea and its activated carbon.

Chem. Eng. J. 168 (2), 707–714.

El Sikaily, A., Khaled, A., El Nemr, A., Said, T.O., Abd-Alla, A.M.A.,

2003. Polycyclic aromatic hydrocarbons and aliphatic in the coral

reef skeleton of the Egyptian Red Sea coast. Bull. Environ.

Contam. Toxicol. 71 (6), 1252–1259.

EPA, 1998. Handbook on Advanced Photochemical Oxidation Pro-

cess, US. EPA, Washington, DC.

Advanced oxidation processes of Mordant Violet 40 dye 9

EPAP/EEAA, 2003. The Egyptian Pollution Abatement Project and

Egyptian Environmental Affairs Agency, Self-Monitoring Manual

for Textile Industry Report.

Furlan, F.R., de Melo da Silva, L.G., Morgado, A.F., de Souza, A.A.

U., Guelli Ulson de Souza, S.M.A., 2010. Removal of reactive dyes

from aqueous solutions using combined coagulation/flocculation

and adsorption on activated carbon. Resour. Conserv. Recy. 54,

283–290.

Gogate, P.R., Pandit, A.B., 2004. A review of imperative technologies

for wastewater treatment I: oxidation technologies at ambient

conditions. Adv. Environ. Res. 8, 501–551.

Khadhraoui, M., Trabelsi, H., Ksibi, M., Bouguerra, S., Elleuch, B.,

2009. Discoloration and detoxicification of a Congo red dye

solution by means of ozone treatment for a possible water reuse. J.

Hazard. Mater. 161, 974–981.

Khaled, A., El Nemr, A., El Sikaily, A., 2003. Contamination of coral

reef by heavy metals along the Egyptian Red Sea coast. Bull.

Environ. Contam. Toxicol. 71 (3), 0577–0584.

Kralicek, P., 1995. Detection of carcinogenic amines that can be

released from certain azoic dyes. Chimia 49, 222–225.

Kusvuran, E., Gulnaz, O., Samil, A., Yildirim, O., 2011. Decoloriza-

tion of malachite green, decolorization kinetics and stoichiometry

of ozone-malachite green and removal of antibacterial activity with

ozonation processes. J. Hazard. Mater. 186 (1), 133–143.

Lin, S.H., Chi, M.L., 1993. Treatment of textile wastewater by

ozonation and chemical coagulation. Water Res. 27, 1743–1748.

Mahmoodi, N.M., Arami, M., 2010. Immobilized titaniananophoto-

catalysis: degradation, modeling and toxicity reduction of agricul-

tural pollutants. J. Alloys Compd. 506, 155–159.

Mallevialle, J., 1982. In: Ozonation Manual for Water and Wastewater

Treatment, vol. 53. John Wiley and Sons, New York.

Mozia, S., Morawski, A.W., Toyoda, M., Inagaki, M., 2008.

Effectiveness of photodecomposition of an azo dye on a novel

anatase-phase TiO2 and two commercial photocatalysts in a

photocatalytic membrane reactor (PMR). Sep. Purif. Technol. 63,

386–391.

Muthukumar, M., Selvakumar, N., 2005. Discoloration of acid dye

effluent with ozone: effect of pH, salt concentration and treatment

time. Color. Technol. 121, 7–12.

Ogunjobi, A.A., Ademola, E.A., Sanuth, H.A., 2012. Toxicity and

bacterial decolourization of textile dyes. Elec. J. Env. Agricult.

Food Chem. 11, 415–423.

Oguz, E., Keskinler, B., Celik, C., Celik, Z., 2006. Determination of

the optimum conditions in the removal of bomaplex red CR-L dye

from the textile wastewater using O3, H2O2, HCO3 � and PAC. J.

Hazard. Mater. 131, 66–72.

Oneill, C., Hawkes, F.R., Hawkes, D.L., Lourenco, N.D., Pinheiro, H.

M., Dele, W., 1999. Colour in textile effluents-source, measure-

ment, discharge consents and simulation: a review. J. Chem.

Technol. Biotechnol. 74, 1009–1018.

Peternel, I., Koprivanac, N., Kusic, H., 2006. UV-based processes for

reactive azo dye mineralization. Water Res. 40, 525–532.

Pielesz, A., Baranowska, I., Rybak, A., Wlochowicz, A., 2002.

Detection and determination of aromatic amines as products of

reductive splitting from selected azo dyes. Ecotoxicol. Environ. Saf.

53, 42–47.

Selcuk, H., Eremektar, G., Meric, S., 2006. The effect of pre-ozone

oxidation on acute toxicity and inert soluble COD fractions of a

textile finishing industry wastewater. J. Hazard. Mater. 37, 254–

260.

Sevimli, M.F., Kinaci, C., 2002. Decolorization of textile wastewater

by ozonation and Fenton’s process. Water Sci. Technol. 45, 279–

286.

Shang, N.C., Yu, Y.H., Ma, H.W., 2002. Variation of toxicity during

the ozonation of monochlorophenolic solutions. J. Environ. Sci.

Health 37A, 261–271.

SMWW, 1985. Standard Methods for the Examination of Water and

Wastewater, 1985. American Public Health Association, Washing-

ton, D.C, pp. 689–823.

Song, S., Xu, X., Xu, L., He, Z., Ying, H., Chen, J., Yan, B., 2008.

Mineralization of CI reactive yellow 145 in aqueous solution by

ultraviolet-enhanced ozonation. Ind. Eng. Chem. Res. 47, 1386–

1391.

Steahlin, J., Hoigne, J., 1982. Decomposition of ozone in water: rate of

initiation by hydroxide ions and hydrogen peroxide. Environ. Sci.

Technol. 16, 676–681.

Swaminathan, K., Pachhade, K., Sandhya, S., 2005. Decomposition of

a dye intermediate, (H-acid) 1 amino-8-naphthol-3,6 disulfonic acid

in aqueous solution by ozonation. Desalination 186, 155–164.

Terry, W., Guido, P., 1989. Acute toxicity bioassays using rotifers. I. A

test for brackish and marine environments with Brachionus

plicatilis. Aquat. Toxicol. 14, 65–80.

USEPA, 1985. United States Environmental Protection Agency,

Methods for Measuring the Acute Toxicity of Effluents to

Freshwater and Marine Organisms. EPA/600/4-85/013, p. 216.

USEPA, 1996. Test Methods for Evaluating Solid Waste, SW-846.

USEPA Office of Solid Waste and Emergency Response, Wash-

ington, DC.

Vanhulle, S., Trovaslet, M., Enaud, E., Lucas, M., Taghavi, S., Van

Der, L.D., Van, A.B., Foret, M., Onderwater, R.C.A., Wesenberg,

D., Agathos, S.N., Schneider, Y.J., Corbisier, A.M., 2008. Decol-

orization, cytotoxicity, and genotoxicity reduction during a com-

bined ozonation/fungal treatment of dye-contaminated wastewater.

Environ. Sci. Technol. 42, 584–589.

Wang, X.J., Chen, S.L., Gu, X.Y., Wang, K.Y., Qian, Y.Z., 2008.

Biological aerated filter treated textile washing wastewater for reuse

after ozonation pretreatment. Water Sci. Technol. 58 (4), 919–923.

Wu, J., Wang, T., 2001. Ozonation of aqueous azo dye in a semi-batch

reactor. Water Res. 35, 1093–1099.

Yasar, A., Ahmad, N., Amanat-Ali-Khan, A., Yousaf, A., 2007.

Decolorization of blue CL-BR dye by AOPs using bleach wastew-

ater as source of H2O2. J. Environ. Sci. 19, 1183–1188.

Zhang, H., Duan, L., Zhang, D., 2006. Decolorization of methyl

orange by ozonation in combination with ultrasonic irradiation. J.

Hazard. Mater. 138 (1), 53–59.

Zhao, W., Shi, H., Wang, D., 2004. Ozonation of Cationic Red X-

GRL in aqueous solution: degradation and mechanism. Chemo-

sphere 57, 1189–1199.