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 CO 2 and H 2 S was investigated. Adsorption isotherms of CO 2 and H 2 S were measured at different temperatures, whereas adsorption at low H 2 S concentrations from 700 to 10000 ppm with balance CO 2 was studied at 298 K. It was found that both CO 2 and H 2 S adsorb and the selectively toward H 2 S versus CO 2 decreases at an increasing H 2 S concentration. Because TRI-PE-MCM-41 hardly adsorbs any of the common gases, such as CH 4, 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 CO 2 and H 2 S. These findings lay the ground for the development of a single-stage process for the removal of CO 2 and H 2 S from biogas, using amine-supported PE-MCM-41.