Leveraging synergistic polar and nonpolar binding sites in a fluorinated metal–organic framework for efficient ethane/ethylene separation

Constructing favorable C2H6-selective adsorbents for one-step C2H4 purification from C2H6/C2H4 mixtures is a matter of considerable significance, but is still a very challenging task in the field of petrochemical industry. Herein, we report a well-designed ant-type metal–organic framework (NUM-16) with appropriate pore size and pore environment for preferential trapping C2H6. NUM-16a (activated NUM-16) performs a high C2H6 uptake of 4.39 mmol/g and a good adsorption selectivity for C2H6/C2H4 (10:90, v/v) mixture at 298 K and 1 bar. The separation mechanism, as unveiled by the grand canonical Monte Carlo simulations and density functional theory calculations, is mainly attributed to synergistic polar and nonpolar binding sites on the pore surface of NUM-16a, which provide stronger affinities to C2H6 than C2H4. Under ambient conditions, dynamic breakthrough experiments revealed that NUM-16a demonstrates the enormous potential for actual C2H6/C2H4 separation and is expected to be applied to the correlative industrial process. Both experiments and theoretical calculations distinctly demonstrated that the reasonable integration of polar and nonpolar binding sites in C2H6-preferred MOFs is a feasible strategy for efficient C2H6/C2H4 separation. This work afforded some useful insights into designing and developing high-powered MOF adsorbents to solve tricky industrial separation challenges.