Hydrogen Sulfide Removal from Biogas Using Carbon Impregnated with Oxidants

Hydrogen sulfide removal from small quantities of gas such as biogas or landfill gas is usually carried out via technologies based on its adsorption onto solid sorbents. Biogas or landfill gas has a high moisture content; thus, for H 2 S removal, nonpolar-activated carbon is the most suitable sorbent. However, the adsorption capacity of common activated carbon for H 2 S is small. Therefore, sorbents that have been properly impregnated are often used because they react with H 2 S to form various products. This leads to great differences among the different sorbents regarding the adsorption capacity and H 2 S removal efficiency. Various commercially available impregnated sorbents for H 2 S capture were tested at different reaction conditions (type of impregnation agent, gas moisture content, and oxygen presence in gas). The test results showed that the H 2 S adsorption capacity of the sorbents is strong depending on the reaction conditions. To properly select a suitable sorbent for a specific industrial application, it is necessary to know the gas composition, in particular, oxygen and water content.