Sciencemadness Discussion Board

Sulfur dioxide treatment

Sunil Sharma - 12-9-2013 at 05:02

Dear all,

I want to remove SO2 from waste aqueous effluent can anybody suggest the best industrial method to treat SO2... other than SO2 aqueous effluent contain Ammonium bromide......

gsd - 12-9-2013 at 05:43

@ Sunil Sharma

Even though this is an amateur science forum, members will be willing to give suggestions on occasional industrial problems provided it is elaborately stated and you have made some efforts to understand and tackle it.

You appear to be a qualified industrial chemist but the way you have stated your problem will put any 10 th grade Chemistry student to shame.

Gsd

Sulfur dioxide treatment

Sunil Sharma - 12-9-2013 at 06:59

@ Gsd

Sir,

Aqueous effluent contain around 10% ammonium bromide, and SO2 (it may be in the form of ammonium and sodium sufites) around 4-5%.. when i evaporate the water i got solid residue that i can manage but the evaporated water contain SO2 (ammonium sulfite), this evaporated water i want to throw in sea but as it contain ammonium sulphite i cannot throw in sea......My idea is to convert sulfite into sulfate using some oxidizing agents i have already tried H2O2 as oxidizing agent but it is giving some operational problem in plant...
So sir can you suggest any other oxidizing agent suitable for industry in my case...

I hope this time i stated the problem in better way....

gsd - 12-9-2013 at 07:21

1) If it contains 10 % NH4Br (i.e. About 8% Br) then you are actually throwing down the money thru' the drain.

In India ( I am assuming your are from India - Andhra Pradesh?) you will find people willing to PAY you to lift this effluent.

2) In my experience, the best (and the cheapest) oxidising agent for SO2 is Manganese Dioxide in the form of Pyrolusite ore which is abundantly available in India.

These should be enough to get you going. If you need any specific aid let me know.

Gsd

Sunil Sharma - 12-9-2013 at 07:37

But MnO2 is insoluble in water...will it work....

gsd - 12-9-2013 at 08:00

Quote: Originally posted by Sunil Sharma  
But MnO2 is insoluble in water...will it work....


???
Of course you will have to make slurry of MnO2 powder in your effluent and stir it vigorously.

I suggest you take help of someone senior with some understanding of chemical engineering at your work place.

Gsd

Antiswat - 12-9-2013 at 09:00

NaHCO3 + SO2 > NaHSO3 + CO2 if im not mistaken

also there could be business in selling the manganese byproducts..

as a rule in chemistry it always works out best if its in the same state, as in powders with powders, liquids with liquids and gasses with gasses
if Cl2 is lead through a slurry of NaHCO3 it is said to be able to produce Cl2O, which isnt something you wanna try, not only toxic but also explosive on contact with organics, basically NCl3 in gas form, not chemically but, both nasty things

Sulfur dioxide treatment

Sunil Sharma - 12-9-2013 at 09:26

Thanks Sir...

AJKOER - 21-9-2013 at 14:14

if creating a sulfate is the goal, try dilute HOCl (from adding a very dilute mineral acid to NaOCl or a weak acid, like acetic acid, to bleach). Reaction:

HOCl + H2SO3 --> H2SO4 + HCl

Hypochlorous acid, per watt's Dictionary of Chemistry, is capable of oxidizing free S, H2S, as well as H2SO3 all the way to Sulfuric acid.

So this suggested process is also capable of addressing more than a SO2 presence in the water (and also disinfects).

If so desired, neutralized the solution with Ca(OH)2, or CaCO3, or NaHCO3,...

AndersHoveland - 21-9-2013 at 16:17

If you simply make sure that the effluent is well aerated, the sulfur dioxide can be oxidized by air to sulfate. This only works if the sulfur dioxide is very dilute and the pH is not too low.

Another method is to use an ozonator. This could be very effective, because the small amounts of nitric oxides produced as a byproduct by the ozonator can help catalyze the oxidation of sulfite by air.

Quote: Originally posted by gsd  
In my experience, the best (and the cheapest) oxidising agent for SO2 is Manganese Dioxide in the form of Pyrolusite ore

bad idea, then the effluent would be contaminated with manganese. even worse

[Edited on 22-9-2013 by AndersHoveland]

gsd - 21-9-2013 at 19:57

Quote: Originally posted by AndersHoveland  
If you simply make sure that the effluent is well aerated, the sulfur dioxide can be oxidized by air to sulfate. This only works if the sulfur dioxide is very dilute and the pH is not too low.



Another method is to use an ozonator. This could be very effective, because the small amounts of nitric oxides produced as a byproduct by the ozonator can help catalyze the oxidation of sulfite by air.

Quote: Originally posted by gsd  
In my experience, the best (and the cheapest) oxidising agent for SO2 is Manganese Dioxide in the form of Pyrolusite ore

bad idea, then the effluent would be contaminated with manganese. even worse

[Edited on 22-9-2013 by AndersHoveland]


Wow! Non-catalytic oxidation of SO2 to SO3 at room temperature! Do you have a patent for this AndersHoveland? This radical technology will make all existing Sulfuric Acid plants obsolete and earn you tons of money.

I also like the idea of Ozonizing voluminous industrial effluent containing about 10 % SO2 by about 3% Ozone produced in an sophisticated equipment - the costs be damned.

BTW Mn is considered as a micronutrient and it's presence in effluent is tolerated to some extend unlike that of other heavy metals like Pb, Cr etc.

And MnO2 treatment is not end of problem. It is just to get rid of SO2. Post This treatment, the effluent must be braught to pH of about 7 to precipitate all soluble metals before discharging.

Gsd