Purification and upgrade of biogas using biomass-derived adsorbents: Review

Abstract

The contaminants in biogas, which include carbon dioxide and hydrogen sulfide, limit its application as engine fuel because they reduce its energy content and cause corrosion to metals. The aim of this study was to review the applications of biomass materials in the purification and upgrading of biogas. The CO 2 adsorption capacity of activated carbon is dependent on the surface area and pore size of the adsorbent. Biochar has a high adsorption capacity of H 2 S, which is dependent on the media alkalinity and the surface chemistry. The capture of CO 2 and H 2 S by biomass adsorbent occurs through both physisorption and chemisorption. An increase in adsorption temperature decreases the adsorption capacity of CO 2 but increases the adsorption capacity of H 2 S for biomass adsorption. Published data indicate that modification with KOH adsorbents improves CO 2 uptake significantly. Furthermore, impregnation of biomass adsorbents with agents like amine compounds can increase the adsorption capacity of H 2 S