Tannic acid coordinated ZIF-8 interlayers regulated polyamide membranes for boosted ion selectivity and antifouling property

Traditional polyamide nanofiltration membranes are restricted by their permeance-selectivity trade-off and fouling intolerance, which collectively constrains efficient ionic separations. To address these, hydroxyl-rich core-shell ZIF-8 nanoparticles were synthesized via tannic acid-mediated coordination (TA/ZIF-8), achieving polyphenol-tailored structural regulation. Herein, the TA/ZIF-8 nanoparticles were engineered to regulate polyamide membranes fabrication via vacuum-assisted filtration by confining interfacial polymerization. Critically, enhanced hydrophilicity and dispersion were induced by TA-Zn 2+ coordination, while monomer diffusion was restricted by the hydrogen bonding between TA/ZIF-8 and piperazine. Consequently, ultrathin polyamide layers characterized by striped/nodular morphologies and elevated roughness were formed. Modulated by the TA/ZIF-8 interlayer, the crosslinking density was reduced, whereas the surface hydrophilicity and electronegativity were simultaneously augmented. As a result, an exceptional water permeance (31.8 L m −2  h −1  bar −1 ) coupled with a high Na 2 SO 4 rejection (98.3%) and a superior Cl − /SO 4 2− selectivity (46.5) was achieved by the optimized membranes. Furthermore, the membranes demonstrated exceptional antifouling property, robust stability, and outperformed literature NF benchmarks. This work establishes TA/ZIF-8 interlayers as a scalable platform for transcending permeability-selectivity limits in antifouling desalination nanofiltration membranes.