Performance evaluation of Zn-Fe adsorbent for H2S adsorption during biogas purification

The trend of research using mixed metal oxide as a selective adsorbent for H2S gas is increasing. Inline with that, this paper evaluated the performance of Zn-Fe/Al2O3 adsorbent in adsorbing H2S as one of the steps in biogas purification process. The Zn-Fe/Al2O3 was successfully synthesized by microwave-assisted wet impregnation technique. The results showed that some operation parameters such as biogas space velocity, H2S inlet concentration, and biogas humidity had obvious influence on the performance of the gas adsorber. At low gas hourly space velocity (GHSV) of 1750 h−1, low H2S inlet concentrations (100 ppm), and no moisture in biogas, the highest breakthrough capacity was achieved with 3.23 mg H2S per gram adsorbent. Fresh and spent adsorbents were characterized by SEM–EDX to investigate the impact of H2S adsorption on the physical properties of the adsorbent. According to the good performance in removing H2S under ambient conditions, the Zn-Fe/Al2O3 is expected to be a promising adsorbent for H2S adsorption in biogas purification process.