H2S in-situ removal from biogas using a tubular zeolite/TiO2 photocatalytic reactor and the improvement on methane production

• A zeolite/TiO2 photocatalytic reactor was developed for H2S in-situ removal.
• The reactor exhibited excellent H2S removal rate and lower SO2 selectivity.
• Bio-methane production was enhanced following H2S in-situ removal.
• The cost-effectiveness of the photocatalytic removal of H2S from biogas was studied.

A tubular photocatalytic reactor filled with zeolite/TiO2 was developed with the objective of H2S selective removal from synthetic gas as well as in-situ removal from raw biogas and its improvement of methane production via anaerobic digestion of waste sludge with 25% addition of swine manure. For the H2S selective removal from synthetic gas, reactor C (containing zeolite/TiO2) is better than reactor D (containing zeolite/TiO2 and TiO2 film), reactor A (containing zeolite) and B (containing TiO2 film). For H2S in-situ removal experiment using reactor C, H2S removal rate reached 98.1% and no SO2 was detected. Furthermore, H2S in-situ removal enhanced biogas production of 4.5% and bio-methane production of 16.1%, compared to the blank control. Considering the excellent H2S removal rate, lower SO2 selectivity and improvement for bio-methane production, H2S in-situ removal using zeolite/TiO2 proved to have promising applications in biogas purification.