Simultaneous Adsorption of H2S and CO2 on Triamine-Grafted Pore-Expanded Mesoporous MCM-41 Silica

The feasibility of using triamine-grafted pore-expanded mesoporous MCM-41 silica (TRI-PE-MCM-41) as a potential adsorbent for simultaneous removal of CO2 and H2S was investigated. Adsorption isotherms of CO2 and H2S were measured at different temperatures, whereas adsorption at low H2S concentrations from 700 to 10000 ppm with balance CO2 was studied at 298 K. It was found that both CO2 and H2S adsorb and the selectively toward H2S versus CO2 decreases at an increasing H2S concentration. Because TRI-PE-MCM-41 hardly adsorbs any of the common gases, such as CH4, H-2, N-2, O-2, and CO, it was inferred that this material may be suitable for the purification of a variety of gas streams containing CO2 and H2S. These findings lay the ground for the development of a single-stage process for the removal of CO2 and H2S from biogas, using amine-supported PEMCM-41.