H2S adsorption on nanostructured iron oxide at room temperature for biogas purification: application of renewable energy

ABSTRACT The energetic use of biogas is limited by the presence of contaminants which hinder the process and generate excessive maintenance costs. This study aims to evaluate the H2S adsorption on nanostructured iron oxide (NIO), towards applications for landfill gas cleaning. The iron oxide utilized in this study is obtained from mining residues, which provides economic and environmental advantages compared to other recognized adsorbents. In order to determine the performance of NIO, adsorption tests were performed in a lab scale with the use of synthetic gas (H2S + N2) and a continuous up-flow reactor. Experiments produced data regarding the process efficiency as a function of different operating conditions including gas hourly space velocity, H2S inlet concentration and gas humidity. Fresh and sulfided samples were characterized by SEM, TEM, BET, EDX and XRD techniques. The characterization results suggest that under lower GHSV (1,250 h-1), lower H2S inlet concentrations (200 ppm) and dry gas, the highest breakthrough capacity was recorded at 2.5 mg H2S per gram of NIO. Due to the good efficiency in removing H2S under ambient conditions, NIO can be considered a cost-effective promising alternative for biogas desulfurization.