Antifouling and flame-retardant oil-water separation membranes via the one-step surface segregation approach

The development of highly efficient, cost-effective, and multifunctional ultrafiltration membranes remains a key goal in oil-water separation technology. This study presents a simple yet effective one-step surface segregation approach to fabricate oil-water separation membranes with both antifouling and flame-retardant properties. These features are critical for enhancing membrane performance, as severe fouling is a major challenge in membrane-based separations, and flame retardancy is essential for the separation of combustible oils and the safe storage of flammable polymer membranes. In this approach, SbCl₃ and PVP were dissolved in the casting solution, while tannic acid (TA) was dissolved in the coagulation bath. During the non-solvent-induced phase separation (NIPS) processes, SbCl₃ hydrolyzed into the Sb₄O₅Cl₁₂and then reacted with TA in formation of the metal-polyphenol coordination to generate the clusters. Simultaneously, PVP spontaneously migrated toward the water phase and bonded with TA via hydrogen interactions. The resulting membrane exhibited outstanding performance, achieving a 94 % permeability recovery rate when separating emulsified oil-water mixtures, excellent self-cleaning performance against oil droplets, and flame resistance when exposed to an open flame. This straightforward and efficient one-step approach offers a promising pathway for the development of advanced multifunctional membranes for oil-water separation applications.