Engineering Pore Environments of Sulfate-pillared Metal-Organic Framework for Efficient C 2 H 2 /CO 2 Separation with Record Selectivity.

Engineering pore environments exhibits great potential in improving gas adsorption and separation performances but requires specific means for acetylene/carbon dioxide (C 2 H 2 /CO 2 ) separation due to their identical dynamic diameters and similar properties. Herein, we report a novel sulfate-pillared MOF adsorbent (SOFOUR-TEPE-Zn) using 1,1,2,2-tetra(pyridin-4-yl) ethene (TEPE) ligand with dense electronegative pore surfaces. Compared to the prototype SOFOUR-1-Zn, SOFOUR-TEPE-Zn exhibits a higher C 2 H 2 uptake (89.1 cm 3 g -1 ), meanwhile the CO 2 uptake reduces to 14.1 cm 3 g -1 , only 17.4% of that on SOFOUR-1-Zn (81.0 cm 3 g -1 ). The high affinity toward C 2 H 2 than CO 2 is demonstrated by the benchmark C 2 H 2 /CO 2 selectivity (16833). Furthermore, dynamic breakthrough experiments confirm its application feasibility and good cyclability at various flow rates. During the desorption cycle, 60.1 cm 3 g -1 C 2 H 2 of 99.5% purity or 33.2 cm 3 g -1 C 2 H 2 of 99.99% purity can be recovered by stepped purging and mild heating. The simulated pressure swing adsorption processes reveal that 75.5 cm 3 g -1 C 2 H 2 of 99.5+% purity with a high gas recovery of 99.82% can be produced in a counter-current blowdown process. Modeling studies disclose four favorable adsorption sites and dense packing for C 2 H 2 . This article is protected by copyright. All rights reserved.