Title : Iron hydroxide-based adsorbent: A case study in removing of H2S from biogas
Abstract:
Methane (CH4) - an important energy source - is the main component of the biogas generated in a Landfill-Based Anaerobic Digestion (LBAD) process but its use in practice is still dependent upon the presence of hydrogen sulfide (H2S). This study was aimed to evaluate the H2S removal efficiency of an economic iron hydroxide-based adsorbent from simulated biogas mixture. The properties of these porous materials such as crystal structures, surface patterns, surface area, pore volume and pore size were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET measurements. Its adsorption capacity was systematically measured as a function of drying temperature conditions, and the process variables like space velocity, retention time, relative humidity as well as the H2S concentrations. In summary, the results obtained from this study are indicated as follows: (i) the behavior of iron hydroxide-based adsorbents for removal of H2S from simulated digester gas mixture does not depend on the drying temperature treatment of samples and relative humidity of the inflow biogas. (ii) H2S removal efficiency increases as H2S concentration increases. This means that the very versatile properties in the different H2S concentration of iron hydroxide-based adsorbents make possible their application with a wide range of biogas and, in addition, they are very effective adsorbent for high-concentration H2S-containing processes.