Anaerobic digesters at dairy farms, wastewater treatment plants and landfills produce valuable biogas. However this gas contains hydrogen sulfide (H2S) which must be removed to protect engines and catalysts. Even trace amounts can damage catalysts used for hydrogen production. The most well known H2S treatment system is an iron sponge. Since the H2S removal capacity of the iron sponge is in the range of 80-90%, a second removal system must be used for applications requiring high level sulfur removal.
Impregnating Granular Activated Carbon (GAC) with alkaline or oxide solids enhances the physical adsorptive characteristics of the carbon with chemical reactions. Sodium hydroxide, sodium carbonate, and potassium hydroxide are common impregnants that can more than double activated carbon