High-Performance Adsorbent for Ethane/Ethylene Separation Selected through the Computational Screening of Aluminum-Based Metal–Organic Frameworks

Abstract

The development of a high-performance ethane (C2H6)-selective adsorbent for the separation of ethane/ethylene (C2H6/C2H4) gas mixtures has been investigated for high-efficiency adsorption-based gas separation. Herein, we investigated Al-based metal–organic frameworks (MOFs) to identify an efficient C2H6-selective adsorbent (CAU-11), supported by a computational simulation study. CAU-11 exhibited numerous advantageous properties (such as low material cost, structural robustness, high reaction yield, and high C2H6/C2H4 selectivity) compared to other Al-based MOFs, indicating immense potential as a C2H6-selective adsorbent. CAU-11 exhibited preferential C2H6 adsorption in single-component gas adsorption experiments, and its predicted ideal adsorption solution theory selectivity of C2H6/C2H4 was over 2.1, consistent with the simulation analysis. Dynamic breakthrough experiments using representative compositions of the C2H6/C2H4 gas mixture confirmed the excellent separation ability of CAU-11; it produced high-purity C2H4 (>99.95%) with productivity values of 0.79 and 2.02 mol L–1 while repeating the cyclic experiment with 1:1 and 1:15 v/v C2H6/C2H4 gas mixtures, respectively, at 298 K and 1 bar. The high C2H6/C2H4 separation ability of CAU-11 could be attributed to its non-polar pore environment and optimum pore dimensions which strengthen the interaction of its pores (via C–H···π interactions) with C2H6 to a greater extent than with C2H4.

Ultramicroporous Metal–Organic Framework with Inert Pore Surfaces for Inversed Separation of Ethylene from C2 Hydrocarbons Mixtures

“…Then, the Q st value for C 2 H 6 is still greater than that for C 2 H 4 with the increase in gas loadings, and the final order of Q st values is C 2 H 2 > C 2 H 6 > C 2 H 4 . Notably, the Q st value of C 2 H 6 at zero loading is higher than those of famous MOFs, such as CAU-11 (31.0 kJ mol –1 ), BUT-315-a (33.4 kJ mol –1 ), JXNU-9 (23.6 kJ mol –1 ), and Fe 2 (BDP) 3 (23.9 kJ mol –1 ) and lower than those of MAF-49 (60 kJ mol –1 ) and NKMOF-8-Br (40.8 kJ mol –1 ) . In addition, the Clausius–Clapeyron equation was also used to obtain the isosteric heat of adsorption.…”