Zhonghua Xiang,† Xuan Peng,‡ Xuan Cheng,† Xiujin Li,§ and Dapeng Cao*,†
†Division of Molecular and Materials Simulation, State Key Laboratory of OrganicInorganic Composites, ‡College of Information Science, and §Department of Environmental Engineering, Beijing University of Chemical Technology, Beijing 100029, China
ABSTRACT: Effectively separating CO2 from the natural gas, which is one of alternative “friendly” fuels, is a very important issue. A hybrid material CNT@Cu3(BTC)2 has been prepared to separate CO2 from the CO2/CH4 mixture. For comparison of separation efficiency, a series of representative metalorganic frameworks (MOF-177, UMCM-1, ZIF-8, MIL-53 (Al), and Cu3(BTC)2) have also been synthesized by the solvothermal method. Adsorption isotherms of CO2 and CH4 pure gases are measured by Hiden Isochema Intelligent Gravimetric Analyzer (IGA-003). The dual-site LangmuirFreundlich (DSLF)-based ideal adsorption solution theory (IAST) is used to predict adsorption of each component in the CO2/CH4 mixture. The IAST-predicted results show that the hybrid material CNT@Cu3(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 CO2/CH4 mixture at 1 < p < 20 bar, which is higher than activated carbons. Moreover, the selectivity of CNT@Cu3- (BTC)2 for the CO2/CH4 mixture keeps almost no change with the composition of CH4, which is one of the excellent properties as a promising separation material. In short, this hybrid material CNT@Cu3(BTC)2 shows great potential in separation and purification of CO2 from various CO2/CH4 mixtures by adsorptive processes in important industrial systems.