Removal of hydrogen sulfide in the gas phase by carbide slag modified bentonite.

Bentonite-based adsorbents for the removal of hydrogen sulfide (H2S) were prepared by a wet-mixing method using carbide slag as the active component. The effects of carbide slag content, calcination temperature, calcination time, and reaction temperature on the H2S adsorption capacity were investigated. The results showed that compared with the blank bentonite adsorbent, the carbide slag-modified bentonite-based adsorbent enhanced the chemisorption of H2S. The adsorption capacity of the carbide slag modified bentonite adsorbent (2.50 mg g-1) was more than 40 times higher than that of the blank bentonite-based adsorbent (0.06 mg g-1) under optimal conditions. The optimal conditions for H2S removal were 3 : 5 ratio of carbide slag-to-bentonite, calcination temperature of 450 °C for 2 h, and reaction temperature of 95 °C. H2S was mainly removed in the mesopores and macropores of the adsorbent and was finally transformed to CaS and sulfate on the adsorbent surface. The adsorption process of H2S followed the Freundlich adsorption isotherm equation and Bangham adsorption kinetic model.