The removal of hydrogen sulfide from biogas by water absorption combined with iron oxide (Fe2O3)

The removal of hydrogen sulfide (H₂S) from biogas is necessary due to the H₂S having corrosive properties to ensure safe biogas utilization. Iron oxide (Fe₂O₃) sorbents are extensively studied for H₂S removal due to their easy operation and low operating cost. This study aimed to measure the efficiency of H₂S removal from biogas by the technique of water absorption combined with Fe₂O₃ chemical adsorption. The biogas flow rate of 1 l/min with an H₂S concentration of 3,000–3,200 ppm was monitored for the experimental time of 60 min. The experiments were tested by varying 100–300 ml water absorbent, 10–40 g Fe₂O₃, and combining 100–300 ml water with 25 g Fe₂O₃. It was found that the volume of water and Fe₂O₃ had significant effects on H₂S removal from biogas. The combination of 300 ml of water and 25 g of Fe₂O₃ has shown promising results, with the highest H₂S removal efficiency of 84.8%. This system offered exceptional techniques of absorption combined with chemical adsorption capacity and, therefore, capable of upgrading biogas to biomethane.