In Situ Modification of Polycrystalline PCN‐250 Membrane for Efficient Separation of Organic Solvent Mixtures

By targeting the secondary building units (SBUs) within the metal–organic framework (MOF) structure, the polycrystalline PCN‐250 MOF membrane was modified through an in situ imidazole functionalization approach. This simple yet effective modification successfully reduced the pore size of the membrane. As a result, the imidazole‐functionalized PCN‐250 membrane achieved efficient separation of methanol‐containing mixtures, including methanol/ n ‐hexane, methanol/dimethyl carbonate, and methanol/toluene. Compared with conventional distillation, pervaporation using this membrane required only 33.4% of the energy to achieve optimal separation performance under identical operating conditions. In addition, the modified membrane achieved high flux while retaining the excellent acid resistance of the original PCN‐250 material, providing a performance advantage over other MOF membranes used in similar applications.