CNT@Cu3(BTC)2 and Metal–Organic Frameworks for Separation of CO2/CH4 Mixture

Effectively separating CO 2 from the natural gas, which is one of alternative “friendly” fuels, is a very important issue. A hybrid material CNT@Cu 3 (BTC) 2 has been prepared to separate CO 2 from the CO 2 /CH 4 mixture. For comparison of separation efficiency, a series of representative metal–organic frameworks (MOF-177, UMCM-1, ZIF-8, MIL-53 (Al), and Cu 3 (BTC) 2 ) have also been synthesized by the solvothermal method. Adsorption isotherms of CO 2 and CH 4 pure gases are measured by Hiden Isochema Intelligent Gravimetric Analyzer (IGA-003). The dual-site Langmuir–Freundlich (DSLF)-based ideal adsorption solution theory (IAST) is used to predict adsorption of each component in the CO 2 /CH 4 mixture. The IAST-predicted results show that the hybrid material CNT@Cu 3 (BTC) 2 exhibits the greatest selectivity among the six materials, and its selectivity keeps in the range of 5.5 to 7.0 for equimolar CO 2 /CH 4 mixture at 1 < p < 20 bar, which is higher than activated carbons. Moreover, the selectivity of CNT@Cu 3 (BTC) 2 for the CO 2 /CH 4 mixture keeps almost no change with the composition of CH 4, which is one of the excellent properties as a promising separation material. In short, this hybrid material CNT@Cu 3 (BTC) 2 shows great potential in separation and purification of CO 2 from various CO 2 /CH 4 mixtures by adsorptive processes in important industrial systems.