Biogas is a valuable renewable energy source used as a fuel or feedstock to produce hydrogen, syngas, and chemicals. In addition to the main constituents, CH4 and CO2, biogas also contains several undesirable contaminants. Although it is in small amounts in biogas, hydrogen sulfide must be removed because it is a toxic and corrosive gas pollutant to the air. Thus, the objective of this study was to investigate the operating conditions of a process for the purification of biogas by removing H2S through a pseudo-catalyst solution based on a fertilizer containing FeEDTA. Then, the operating conditions were optimized to obtain maximum H2S removal and minimum degradation of the pseudo-catalyst solution. Operating at the optimum conditions, a maximum H2S absorption capacity and a minimum pseudo-catalyst solution degradation rate achieved were 0.83 molH2S/molPCS and 0.020%/min, respectively. Therefore, oxidative absorption using a pseudo-catalyst solution based on a fertilizer containing FeEDTA is a potential route for biogas purification.