Screening and Design of COF-Based Mixed-Matrix Membrane for CH4/N2 Separation

Abstract Membrane separation is a high-efficiency, energy-saving, and environment-friendly separation technology. Covalent organic framework (COF)-based mixed-matrix membranes (MMMs) have broad application prospects in gas separation and are expected to provide new solutions for coal-bed methane purification. Herein, a high-throughput screening method is used to calculate and evaluate COF-based MMMs for CH4/N2 separation. General design rules are proposed from thermodynamic and kinetic points of view using the computation-ready, experimental COFs. From our database containing 471671 generated COFs, 5 COF membrane materials were screened with excellent membrane selectivities, which were then used as the filler of MMMs for separation performance evaluation. Among them, BAR-NAP-Benzene_CF3 combined with polydimethylsiloxane and styrene-b-butadiene-b-styrene show high CH4 permeability of 4.43×10–13 mol·m·s–1·Pa–1·m–2 and high CH4/N2 selectivity of 9.54, respectively. The obtained results may provide reasonable information for the design of COF-based membranes for the efficient separation of CH4/N2.