Amine-Grafted MCM-48 and Silica Xerogel as Superior Sorbents for Acidic Gas Removal from Natural Gas
In an effort to develop selective solid sorbents for acidic gas (CO 2 and H 2 S) removal from natural gas mixtures, we synthesized amine-surface-modified silica xerogel and MCM-48 materials. With large amounts of basic amine groups on the surface, the sorbents are able to selectively bind the acidic gases CO 2 and H 2 S. High adsorption capacities and adsorption rates were obtained for both gases. The adsorption−desorption isotherms of the gases and thermogravimetric analysis of the sorbents showed that these sorbents can be regenerated completely under mild conditions such as those used in pressure swing or temperature swing adsorption processes. We have also investigated the effect of moisture on the adsorption of CO 2 and H 2 S by TPD-MS and infrared spectroscopy. The results indicated that the presence of water vapor doubled the amount of CO 2 adsorbed and barely affected the H 2 S adsorption.