Preferential Adsorption Performance of Ethane in a\nRobust Nickel-Based Metal–Organic Framework for Separating\nEthane from Ethylene

Abstract

Development of an\nethane-selective adsorbent to separate ethane\nfrom ethylene is a challenging issue with great significance for ethylene\npurification. The adsorptive separation technique based on physical\nadsorption holds a great promise to address this issue. Herein, we\nreport a robust ethane-selective metal–organic framework, Ni­(BODC)­(TED),\nand investigate its separation performance on C₂H₆/C₂H₄. The as-synthesized Ni­(BODC)­(TED) exhibits\nexcellent water vapor stability and high capacity of C₂H₆ molecules with an uptake of 3.36 mmol/g at 298 K and\n100 kPa, higher than those of many adsorbents reported in recent years.\nIts C₂H₆/C₂H₄ selectivity\npredicted by the ideal adsorbed solution theory (IAST) model reaches\n1.79. A molecular simulation is applied to unveil the preferential\nadsorption mechanism of ethane. Calculation shows that five strong\nC–H···H interactions are formed between C₂H₆ and the framework of Ni­(BODC)­(TED), and the\nisosteric heat of ethane on Ni­(BODC)­(TED) is 27.02 kJ/mol, higher\nthan that of ethylene, resulting in preferential adsorption of ethane.\nNi­(BODC)­(TED) would become a promising member of the family of ethane-selective\nmaterials for the industrial separation of ethane from ethylene.