SYNTHESIS AND CHARACTERIZATION OF BIMETALLIC MOF HKUST-1(CU, MG) ADSORBENTS AND THEIR APPLICATION IN NATURAL GAS PURIFICATION

Abstract

Carbon dioxide (CO2) is one of the most important greenhouse gases and its removal from natural gas by adsorption is highly desirable. This study investigates the synthesis process of the bimetallic metal-organic framework, HKUST-1(Cu, Mg) and its potential use in natural gas purification by preferentially adsorbing CO2 from CO2/CH4 mixture. HKUST-1(Cu, Mg) was prepared by solvothermal method at different temperatures (100-200 °C). The resulting MOFs were characterized by various analytical techniques (XRD, SEM, FTIR, and TGA). The experimental results showed that single metal MOF HKUST-1 can be prepared at 100 °C, whereas the bimetallic HKUST-1(Cu, Mg) can be prepared by raising the temperature to 180 °C. Furthermore, the synthesized single and bimetallic MOFs were studied for their CO2/CH4 separation performance. The sorption results showed that the partial substitution of Cu metal with Mg metal in the framework of bimetallic HKUST-1(Cu, Mg) enhanced the CO2 uptake and its selectivity over CH4 by 31.7%, and 38.60%, respectively, which can be attributed to changes in surface areas, pore structures and additional open metal site (OMS) induced by the secondary metal. These findings shed light on the optimal synthesis conditions and highlight the CO2 separation efficiency of HKUST-1(Cu, Mg) in natural gas upgrading.