An ethane-trapping Zn (II) cluster-based metal-organic framework with suitable pockets for efficient ethane/ethylene separation

Abstract

Efficient separation of ethane (C2H6) from ethylene (C2H4) using C2H6-selective adsorbents is more efficient but challenging due to their similar physical and chemical properties. Herein, we report a Zn (II) cluster-based metal-organic framework, Zn4O(NTB)2, with suitable cavity pockets and favorable adsorption sites for the reverse capture of C2H6 from C2H6/C2H4 mixtures. Both high C2H6 uptake (2.83 mmol g−1) and C2H6/C2H4 selectivity (2.06) at 273 K and 1 bar was achieved, outperforming many top-ranking C2H6-selective adsorbents. Moreover, dispersion-corrected density functional theory (DFT) and grand canonical Monte Carlo (GCMC) simulation revealed that CH···O and CH···π interactions are formed with C2H6 in the suitable pockets with saturated Zn clusters and nonpolar pore surfaces. Dynamic breakthrough experiments demonstrated its practical separation performances with various gas-mixture compositions and those containing water vapor.