The best ammonia absorbent is diluted sulphuric acid. If the emission is directed by suction or bubbling through diluted sulphuric acid (as diluted as 0.05 M H2SO4) you could scrub much of the ammonia. The concentration of sulphuric acid used depends on staff safety and the amount of ammonia scrubbed but it can be adjusted to your needs. Ammonia saturation in scrubbed acid can be checked by pH meter other chemical methods with neutral pH indicating saturation. The ammonia scrubbed produces a good fertiliser ammonium sulphate in solution which can be processed if you liaise with a fertiliser company hence does need to be dumped as waste.

The best and simplest way is to under a counter-current absorption column for the purpose. The ammonia gas will flow upwards in the column against water spray. The ammonia gas is water soluble and will dissolve in water and form NH4OH (ammonium hydroxide).

NH3 + H2O = NH4OH

Hope this helps answer your question.

Professor Yehia Khalil, Yale University, USA

Fellow of the University of Oxford, UK

According to my opinion the best method should be selected according to ammonia concentration in the waste stream. Whem the concentrations are low (up to 1000 mg.m-3), the best and economically most feasible is biofiltration.

Regards

Vit 

Dear Nauman,

I agree with Selva to scrub the ammonia gas with dilute acid for complete (over 99%) recovery and neutralization of the alkaline ammonia gas as compared to just water.

In addition, if you prefer to convert the waste ammonia gas into a valuable nutrient/fertilizer then use phosphoric instead of sulfuric acid as to produce di-ammonium phosphate (DAP) which is commonly used both in agriculture and in biological wastewater treatment.

Regards,

Bruno