CH4/N2 adsorption separation research of MOFs with divalent Cr/Mo/Ni unsaturated metal sites
(2.Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization, Taiyuan, Shanxi, China 030024)
【Abstract】Based on the strong interaction energy between the coordinatively unsaturated metal sites (UMSs) and the gas molecules, M-BTC (M = Cr, Mo, Ni), isostructural with HKUST-1 (Cu-BTC), were successfully synthesized via the coordination reaction of the high-activity divalent metal (Cr2+/Mo2+/Ni2+) and organic ligand (H3BTC), and then the impact of gas–metal interactions on the selective adsorption of CH4 from N2 was investigated by comparing with classical materials (Cu-BTC). The results show the good CH4 selective adsorption properties of M-BTC (M = Cr, Mo, Ni) with UMSs. Among these materials, Ni-BTC with unsaturated Ni2+ sites presents the highest adsorption heat value for CH4, leading to the excellent CH4/N2 adsorption separation properties; but the Cr-BTC with high Cr2+ activity shows the lower ability for CH4/N2 separation than Cu-BTC. Taking into consideration the IAST calculation results, we verified the ability for the selective adsorption of CH4 molecules on M-BTC (M = Cr, Mo, Ni) and Cu-BTC followed as Ni-BTC > Mo-BTC > Cu-BTC > Cr-BTC.
【Keywords】 methane; nitrogen; adsorption; adsorbents; coordinatively unsaturated metal sites;
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