Facile synthesis of micro-eggette patterned nanofiltration membrane with enhanced anti-fouling and rejection performance

Widespread application of the nanofiltration (NF) technique in wastewater reuse is still hindered by the NF membrane's fouling propensity and rejection efficiency. This study presents the fabrication of a micro-patterned NF (M-NF) membrane structured with micro-eggette morphology for simultaneously enhancing anti-fouling and rejection performance. The M-NF membrane was synthesized by combining optimized micro-molding phase inversion and classic interfacial polymerization reaction. Microscopic characterization and chemical analysis confirmed the formation of uniform 4 μm height patterns and the crosslinked polyamide layer. Separation and fouling tests demonstrated that the M-NF membrane possesses better anti-fouling and rejection performance. Ex-situ and in-situ fouling tests illustrated that, compared to the control membrane, the M-NF membrane could maintain high water permeation during fouling filtration while showing reduced flux decline, greater fouling resistance, and less fouling deposition owing to its enhanced trough and crest by micro-eggette morphology. The M-NF membrane also achieved 5–38 % higher mono/di-valent salts rejection and 6–8 % higher PFOS rejection than that of the NF270 membrane. Further computational fluid dynamics simulations showed that the surface pattern-disturbed hydrodynamic flow promoted the hydrodynamic forces exerted on the pollutant molecules. This work demonstrates the strong potential of membrane surface patterning for improving novel NF membranes' antifouling and rejection abilities.