Hydrogen sulfide removal from the waste gas of phosphoric acid plant

The wet manufacturing process of the phosphoric acid plant generates a waste gas containing hydrogen sulfide (H2S), a malodorous and toxic gas. In this study, a new application, coupling the neutralization in potassium hydroxide (KOH) solution and the catalytic oxidation (designated as KOC), was developed to treat H2S. In fact, the waste gas of the phosphoric acid plant was neutralized in KOH solution in the presence of the air oxygen as an oxidizing agent and the activated carbon (AC) prepared from an agricultural waste, that is, the olive stone, as a catalyst. The process was efficient in both batch and cyclic configurations. The KOC batch process offers the retention of more than 40 mgS and allows high removal of H2S compared to absorption alone. The KOC cyclic process treated 800 mgS/g of AC.