Defect-Engineered Ultrathin Zeolitic Imidazolate Frameworks-8 Membranes: Unlocking Ultrafast Water Transport and Precise Molecular/Ionic Sieving

The rational design of high-performance metal–organic framework (MOF) membranes for sustainable saline wastewater treatment remains a critical challenge in addressing global water scarcity. Herein, we report an ultrathin zeolitic imidazolate frameworks-8 (ZIF-8) membrane with precisely engineered missing-linker defects, fabricated through a dual metal source strategy, followed by controlled ligand thermolysis. This process precisely introduces missing-linker defects while minimizing the intercrystalline voids. The resultant architecture, characterized by enhanced water affinity, enlarged effective pore apertures, coupled with reduced membrane thickness, enables ultrafast molecular transport, achieving ultrahigh water permeance of 122.5 L m –2 h –1 bar –1 while maintaining near-complete dye rejection (>99.8%). Notably, the membrane exhibits minimal NaCl rejection (9.4%), yielding a salt/dye separation factor of 303.2, surpassing all reported nanofiltration membranes. This work establishes controlled defect engineering as a powerful strategy to overcome the permeability-selectivity trade-off, providing a promising platform for single-step purification of dye-contaminated saline streams.