Analysis of SO2 in Ambient Air

8/2/2019 Analysis of SO2 in Ambient Air

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Envirotech Centre for Research & Development

New Delhi


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Dissolve 10.86 gm Mercuric chloride

+

0.066 gm EDTA

+

6.0 gm Potassium chloride

And make upto 1000ml with distilled water


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Sulphamic acid Solution (0.6%)

Dissolve 0.6 gm Sulphamic acid in 100 ml distill water.

formaldehyde Solution (0.2%)

Take 1.25 ml formaldehyde Solution (36-38%) andmake upto 250 ml with distill water.


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Pararosaniline Solution (PRA)

Stock PRA solution:Dissolve 0.5 gm of Parasoaniline in 100 ml distill water

& keep it upto 48 hour.

Working PRA solution:Take 10 ml Stock PRA solution

+

15 ml Concentrated HCl

and make upto 250 ml with distill water.


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Stock Iodine solution (0.1N)

Dissolve 1.27 gm of Iodine

+

4.0 gm potassium iodide

+25 ml distill water, stir untill whole matter is dissolved


Working Iodine solution (0.01N)

Take 50ml of stock iodine solution and make upto 500ml withdistill water

(This solution is stored in amber color glass bottle.)


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Starch Indicator

Dissolve 0.4 gm of Soluble starch

+0.002 gm Mercuric iodide in small amount of water &

make a paste

Add 200ml distilled water & boil until clear solution


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Primary Standard Potassium Iodate Solution

Dissolve 1.5 gm of Potassium Iodate (oven dried at

180C)


(Prepare freshly)


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Stock Sodium Thiosulphate Solution (0.1N)

Dissolve 6.25 gm of Sodium Thiosulphate

+0.025 gm Sodium carbonate

In 250 ml boiled & cooled distill water

Stand for one day before standardization


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Stock Sulphite Solution

Dissolve 0.15 gm of Sodium metabisulphite

In 250 ml boiled & cooled distill water

1ml = 320 400ug SO2, Find actual concentration

after Standardization


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Standardization of Soduim thiosulphate solutionTake 50 ml of Sodium Iodate Solution in 250 ml Iodine

Flask.

Add 2.0 gm Potassium Iodide & 10ml of (1 : 10) HCl.

Put Stopper on the flask and allow to react for 5.0 min.

Titrate with stock sodium thiosulphate solutio to a paleyellow color.

Add 2 5 ml starch indicator, it shall give blue color.Continue Titration up to disappearance of color.


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Standardization of Soduim thiosulphate solution

Calculate the normality as follows:-

N = w 103

0.1 OR N= 2.8 WV 35.67 V

Where:-

W = Weight of Potassium Iodate, gm (Primary Standard)

V = Volume of Sodium Thiosulphate Solution consumed (ml).

35.67 = Equivalent wt. of Potassium Iodate.

N = Normality of Sodium Thiosulphate.


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Working Soduim thiosulphate solutionCalculate the required volume of Stock Sodium Thiosulphate

solution to prepare a required volume of working sodium

thiosulphate solution

N1V1=N2V2

N1 = Normality stock Sodium Thiosulphate Solution (0.1N)

V1 = volume of Stock Sodium Thiosulphate solution

N2 = Normality of warking Sodium Thiosulphate (0.01N)V2 = Required volume of working Sodium thiosulphate solution

Take..ml of stock sodium thiosulphate solution and make upto.ml with freshly boiled & cooleddistilled water.


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Iodine Flask250ml (for Blank) Iodine Flask250ml (for Sample)

Pipette 50ml of 0.01N Iodine Solution Pipette 50ml of 0.01N Iodine Solution

Add 25ml distill water Add 25ml Stock Sulphite solution

Stopper the flask & allow to react for 5.0 minutes

Titrate each flask in turn to a pale yellow with working Sodium thiosulphate

solution (0.01N)

Add 5.0ml starch solution to each flask (it gives blue color to solution)

Note the volume of 0.01N Sodium thiosulphate solution consumed for Blank &

Sample

For blank consumed Sodium thiosulphate

is V1mlFor sample consumed Sodium

thiosulphate is V2ml


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Calculation for Strength of Stock Sulphite solution

C = (V1-V2) x N x K

V

Where

C = Concentration of SO2 (g/ml)

V1 = Volume of sodium thiosulphate solution (0.01N) consumed

for Blank (ml)

V2 = Volume of sodium thiosulphate solution (0.01N) consumed

for Sample (ml)

N = Normality of sodium thiosulphate solution

K = 32000 Miliequivlent wt. of SO2/g

V = Volume of sulphite Solution (25ml)


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Working Sulphite solutionTake 2.0ml of Stock Sulphite solution

And make upto 100ml with absorbing media (TCM 0.04M)

Strength of Working Sulphite solution=

C x 2

100Where

C = Concentration of Stock Sulphite Solution (gSO2/ml)


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VolumetricFlask 25mlBlank 25mlSample1 25mlSample2 25mlSample3 25mlSample4 25mlSample5

Working

Sulphite Sol

0.0ml 0.5ml 1.0ml 1.5ml 2.0ml 3.0ml

Absorbing

Media

10ml 9.5ml 9.0ml 8.5ml 8.0ml 7.0ml

Sulphamic

acid

1.0ml 1.0ml 1.0ml 1.0ml 1.0ml 1.0ml

Keep all volumetric flask for 10 minutes to destroy the nitrite resulting from

oxide of Nitrogen

Formaldehyde Sol.

2.0ml 2.0ml 2.0ml 2.0ml 2.0ml 2.0ml

Working

PRA

2.0ml 2.0ml 2.0ml 2.0ml 2.0ml 2.0ml

Make upto 25ml with distill water, Mix thoroughly , After 30 minutes measure

absorbance of each flask at 560nm wavelength


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Plot calibration curve with absorbanceversus concentration of SO2


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Volumetric Flask 25mlFor Blank 25mlFor sample

Exposed absorbing Media 0 ml 10ml

Absorbing Media 10ml 0ml

Sulphamic acid 1.0ml 1.0ml

Keep all volumetric flask for 10 minutes to destroy the nitrite resulting from

oxide of Nitrogen

Formaldehyde Sol. 2.0ml 2.0ml

Working PRA 2.0ml 2.0ml

Make upto 25ml with distill water, Mix thoroughly , After 30 minutes measure

absorbance of each flask at 560nm wavelength


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Total volume of air passed through Noximpinger (V, in liter)

Avg. Flow Rate (lpm) X Time (minute)


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Concentration (ug SO2/m3)=

C x A x 1000 x D

V x B

Where:

C= SO2 Curve value

A= Absorbing reagent taken for sampling, ml

V= Volume of sampled airB= Volume taken for sample analysis, ml

D= Dilution factor

1000 for conversion from liter to m3

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Analysis of SO2 in Ambient Air