High performance ultrafiltration membrane by coupling magnetic migration and in-situ surface modification

Ultrafiltration (UF) membrane technology has drawn much attraction during the past decades to address the challenge of global clean water scarcity. Herein, we proposed a facile methodology to prepare a gradient polysulfone-based (PSf) UF membrane with effective antifouling properties via coupling magnetic field-assisted directional migration and in-situ hydrolysis of fluoro-agent during non-solvent induced phase separation (NIPS). The effect of GO-Fe3O4 gradient distribution and fluorosilane (FAS) in-situ surface modification on membrane morphology, hydrophilicity, porosity, water flux and antifouling properties have been investigated. Optical microscopy and SEM-EDX observations indicated that hydrophilic GO-Fe3O4 nanofiller could directionally migrate in casting solution and eventually result in gradient distribution in PSf matrix under the magnetic field. In addition, the surface enrichment of GO-Fe3O4 provided reaction sites to anchor low energy FAS via in-situ hydrolysis on the membrane surface and realized dual antifouling mechanism (fouling-resistance and fouling-release), which guaranteed UF membranes with excellent antifouling properties and remarkable long-term stability and reusability. Our study provided a new incentive to the development of high performance UF membranes by coupling magnetic migration and in-situ surface modification.