Preparation of Cu-BTC MOF extrudates for CH4 separation from CH4/N2 gas mixture

Abstract

Metal-Organic Frameworks (MOF) are promising materials for gas separation and storage. The shaping of MOFs is an essential step for their practical industrial application. In this work, Cu-BTC MOF extrudates (B-5, B-10, and B-15) were prepared by using 5, 10, and 15 wt% of carboxymethyl cellulose as a binder and well characterized by powder X-ray diffraction (PXRD), N2 adsorption-desorption at 77 K, FTIR, TGA, and Scanning Electron Microscopy (SEM). The equilibrium adsorption isotherms of CH4 and N2 with Cu-BTC extrudates were measured at 298, 313, and 328 K and up to 10 bar pressure and compared with zeolite 13X and 5A. The isotherm data of both adsorbates were fitted in Dual Site Langmuir equations, and adsorption selectivity of methane over nitrogen was predicted using Ideal Adsorbed Solution Theory (IAST) method for 20:80, 30:70, and 50:50 (mol%/mol%) CH4/N2 feed gas mixtures representing nitrogen bearing coal bed methane. The CH4/N2 selectivity of Cu-BTC extrudates B-5, B-10, and B-15 was higher than commercial zeolite 13X and 5A. For example, for the 20:80 CH4/N2 feed mixture, the CH4/N2 selectivity of Cu-BTC extrudates B-5, B-10, and B-15 was 3.21, 3.24, and 3.25, respectively, which are about 38 & 34% higher than zeolite 13X and 5A which makes them potential adsorbent for further dynamic studies for the said separation application.