Synthesis of Fe/MgO nano-crystal catalysts by sol–gel method for hydrogen sulfide removal

The Fe/MgO nano-crystal catalysts were synthesized for removal of hydrogen sulfide (H2S) in a biogas. The nano-crystalline catalyst supporting powders, magnesium oxide (MgO), were obtained by sol–gel method. Ferric ion from ferric nitrate solution was supported on the MgO nano-crystal powders to give 17.5 nm Fe/MgO crystal size by wet impregnation and calcinations. Catalytic activity for H2S oxidation was carried out in a semi-batch reactor. Fe/MgO nano-crystal catalysts were held in an aqueous suspension with simulated H2S gas bubbling for catalytic oxidation and regeneration. The catalysts showed marked catalytic properties such that elemental sulfur was produced during the regeneration with air. Fresh and spent catalysts were characterized by XRD, EDX, FTIR, TEM, and CHNS techniques. The performance of the synthesized Fe/MgO catalysts on H2S oxidation from a biogas was examined using a packed column scrubber. The results show that the H2S was specifically absorbed and oxidized by the Fe/MgO catalysts suspension at room temperature. The scrubbing process performed with no absorbing or reaction of CH4 and CO2 from the biogas.