Abstract
The separations of CO2/CO/CH4/H-2, CO2/H-2, CH4/H-2, and CO2/CH4 mixtures at pressures ranging to 7 MPa are important in a variety of contexts, including H-2 production, natural gas purification, and fuel-gas processing. The primary objective of this study is to demonstrate the selective adsorption potential of an rht-type metal-organic framework [Cu-3(TDPAT)(H2O)(3)]center dot 10H(2)O center dot 5DMA (Cu-TDPAT), possessing a high density of both open metal sites and Lewis basic sites. Experimental high pressure pure component isotherm data for CO2, CO, CH,, and H-2 are combined with the Ideal Adsorbed Solution Theory (IAST) for estimation of mixture adsorption equilibrium. The separation performance of Cu-TDPAT is compared with four other microporous materials, specifically chosen in order to span a wide range of physicochemical characteristics: MgMOF-74, MIL-101, LTA-5A, and NaX. For all mixtures investigated, the capacity of Cu-TDPAT to produce the desired product, H-2 or CH4, satisfying stringent purity requirements, in a fixed bed operating at pressures exceeding about 4 MPa, is either comparable to, or exceeds, that of other materials.