Removal of hydrogen sulfide from biogas by adsorption and photocatalysis: a review

Biogas is a renewable fuel produced from modern biomass, yet biogas contains traces of hydrogen sulfide, a toxic compound, that must be removed before biogas usage. Here we review the removal of hydrogen sulfide by biological treatment, chemical treatment, porous solid treatment and photocatalysis. Adsorption and photocatalysis methods are compared by figures of merit calculations. Adsorption is used commercially but is limited by the lifespan of adsorbent materials. Photocatalysis appears as an affordable alternative, and the combination of adsorption and photocatalysis is promising. The figure of merit calculation appears as a good indicator of the performance of adsorbent materials and photocatalysts.