Modulator regulated Zr-MOF membrane for organic azeotropic separation

High-connectivity metal-organic framework (MOF) membranes with high chemical stability and tunable pore structure have shown great potential for liquid molecular separation. However, it remains a challenge to construct intrinsic lattice apertures in MOF membranes to achieve high separation efficiency owing to the presence of angstrom-sized lattice defects. Herein, for the first time, we report a modulator engineering strategy to prepare a high-connectivity Zr-MOF, MOF-801 membrane for separating organic azeotropic mixtures via pervaporation. The relationship between the concentration and acidity of modulators (formic acid, acetic acid, and trifluoroacetic acid) in synthesis system and pore aperture in MOF membrane was investigated systematically. Benefiting from weakening competitive coordination effect between modulator and ligands to construct intrinsic lattice, the optimized MOF membrane prepared by 15 % of acetic acid exhibited excellent separation performance with flux of ∼3700 g m⁻² h⁻¹ and separation factor of ∼630 for methanol/dimethyl carbonate (DMC) mixture with methanol content of 10 wt% at 40 °C, surpassing the separation performance of state-of-the-arts membranes. Our work provides a facile approach to precisely manipulate the lattice aperture of MOF molecular sieving membranes.