Crosslinking mineralized interlayer engineering of in situ self-cleaning nanofiltration membranes based on polyethylene substrates

Conventional nanofiltration (NF) membranes are limited by their greater thickness and less stable ultrafiltration substrates, as well as the significant challenges posed by membrane fouling. In this work, we developed composite NF membranes with a multifunctional mineralized interlayer through metal polyphenol network (MPN) precursor-mediated cross-linking mineralization on hydrophobic polyethylene (PE) substrates. The incorporation of a mineralized layer enhanced the wettability of PE and optimized the structure of polyamide (PA) via an interlayer modulation strategy, resulting in PA-Fe 3 O 4 -PE membranes exhibiting water permeance up to 21.9 LMH bar −1 and selectivity up to 68.8 for Cl - /SO 4 2- . Furthermore, PA-Fe 3 O 4 -PE displayed a highly polarized surface that significantly improved its antifouling properties. The confined space within PA-Fe 3 O 4 -PE enabled efficient regeneration through in situ self-cleaning, achieving flux recovery above 95% during all three fouling-regeneration cycles while maintaining high stability and recoverability under extreme real-world wastewater conditions. This study provides novel insights into the preparation of multifunctional composite NF membranes and their sustainable application in water treatment.