H2S adsorption/oxidation on materials obtained using sulfuric acid activation of sewage sludge-derived fertilizer

Sewage sludge-derived fertilizer, Terrene, was used as a precursor of adsorbents tested for removal of hydrogen sulfide from moist air. The adsorbents were obtained by pyrolysis of sulfuric acid-treated granular fertilizer at 600, 800, and 950degreesC in a nitrogen atmosphere. The highest H2S removal capacity was obtained for the sample carbonized at 950degreesC. This is a result of a combined effect of the specific chemistry of the inorganic phase and the development of microporosity within the carbon deposit. On the surface of the materials studied hydrogen sulfide is converted to elemental sulfur, sulfides, and sulfates as a result of the reaction with salts/oxides and the presence of an oxidizing atmosphere. The pores are gradually filled as the surface reactions proceed. The removal of H2S occurs until all the small micropores are filled with the reaction/oxidation products. (C) 2002 Elsevier Science (USA).