Preparation of Amino-Functional UiO-66/PIMs Mixed Matrix Membranes with [bmim][Tf2N] as Regulator for Enhanced Gas Separation

Development of mixed matrix membranes (MMMs) with excellent permeance and selectivity applied for gas separation has been the focus of world attention. However, preparation of high-quality MMMs still remains a big challenge due to the lack of enough interfacial interaction. Herein, ionic liquid (IL)-modified UiO-66-NH2 filler was first incorporated into microporous organic polymer material (PIM-1) to prepare dense and defect-free mixed matrix membranes via a coating modification and priming technique. IL [bmim][Tf2N] not only improves the hydrophobicity of UiO-66-NH2 and facilitates better dispersion of UiO-66-NH2 nanoparticles into PIM-1 matrix, but also promotes the affinity between MOFs and polymer, sharply reducing interface non-selective defects of MMMs. By using this strategy, we can not only facilely synthesize high-quality MMMs ignoring non-selective interfacial voids, but also structurally regulate MOF nanoparticles in the polymer substrate and greatly improve interface compatibility and stability of MMMs. The method also gives suitable level of generality for fabrication of versatile defect-free MMMs based on different combination of MOFs and PIMs. The prepared UiO-66-NH2@IL/PIM-1 membrane exhibited outstanding gas separation behavior with large CO2 permeation of 8283.4 Barrer and high CO2/N-2 selectivity of 22.5.

Automated summary

Development of mixed matrix membranes (MMMs) with excellent permeance and selectivity for gas separation has garnered global attention. By incorporating ionic liquid (IL)-modified UiO-66-NH2 filler into microporous organic polymer material (PIM-1), researchers have successfully prepared dense and defect-free MMMs. The IL not only enhances the hydrophobicity of the filler and promotes better dispersion into the matrix, but also reduces non-selective defects at the interface, improving overall membrane performance.