Constructing polyamide nanofiltration membranes via interfacial growth of aminated ZIF-8 for enhanced flux and selectivity

To address the structural defects and performance limitations caused by nanoparticle aggregation and insufficient interfacial compatibility in conventional thin-film nanocomposite polyamide (PA) nanofiltration membranes, an interfacial engineering strategy was developed to construct organic solvent nanofiltration membranes via the in situ growth of amino-functionalized ZIF-8 (ZIF-8-NH 2 ) nanoparticles. A continuous and well-anchored ZIF-8-NH 2 interlayer was introduced between the polyimide support and the PA selective layer, which effectively mitigated nanoparticle aggregation and enhanced interfacial integrity, thereby promoting the formation of a dense and uniform PA layer. Performance evaluation demonstrated that, at an optimized ZIF-8-NH 2 growth cycle of three, the resulting membrane exhibited a pure-water permeance of 41.3 L·m −2 ·h −1 ·bar −1 and a methanol permeance of 16.9 L·m −2 ·h −1 ·bar −1 , while achieving rejection values of 65.1 % for NaCl and 99.9 % for Na 2 SO 4 . In ethanol, the membrane exhibited a low molecular weight cutoff of 456 g·mol −1 and maintained Congo red rejection above 99 % during continuous operation for 5 days, confirming its structural stability and operational durability.