Sewage sludge-derived materials as efficient adsorbents for removal of hydrogen sulfide

Sewage sludge-derived materials were used as adsorbents of hydrogen sulfide from moist air. The adsorbent obtained by carbonization at 950 degreesC has a capacity twice of that of coconut shell-based activated carbon. The capacity of the sludge-derived materials increases with increasing carbonization temperature. It is likely that during carbonization at 950 degreesC a mineral-like phase is formed that consists of such catalytically active metals as iron, zinc, and copper. The results obtained demonstrate that the presence of iron oxide significantly increases the capacity of commercial carbon and activated alumina. The sludge-derived adsorbents are efficient for hydrogen sulfide removal until the pore entrances are blocked with sulfur as the product of oxidation reaction. For materials in which the catalytic effect is predominant, hydrogen sulfide is adsorbed until all pores are filled with sulfur. There is also indication that chemisorption plays a significant role in the removal of hydrogen sulfide from moist air.