Synergistic Multiscale Design of Metal–Organic Framework Membrane via Biomineralization-Inspired Templating for High-Efficiency Azeotrope Separation

Membrane-based pervaporation offers an energy-efficient route for azeotrope separation, yet fabricating membranes that combine structural integrity with precise molecular sieving remains challenging. This work introduces a biomineralization-inspired strategy to synergistically engineer metal-organic framework MIL-100 membranes across micro-, nano-, and molecular scales by using a readily accessible and metastable CuBTC template membrane. The template-anchored point-by-point nucleation directs spatially precise assembly of MIL-100 nanocrystals into a dense, defect-free membrane. Concurrently, a dynamic competition between template "sacrifice" and preservation generates a hierarchical "ship-in-bottle" structure, where encapsulated CuBTC nanoclusters effectively narrow MIL-100 mesocages to molecular dimensions, enabling sharp water/organic discrimination. For a 90 wt % ethanol/water feed, it achieves a separation factor of 3200 with a flux of 2.58 kg m^-2 h^-1, outperforming state-of-the-art membranes. This bioinspired mineralization strategy provides a universal route for designing crystalline porous membranes with exceptional selectivity and stability for energy-efficient molecular separations.