In-situ mineralization of photocatalytic Ag/Ag3PO4 for self-cleaning ultrafiltration membranes

Photocatalytic membranes have emerged as promising catalytic oxidation materials to mitigate fouling with self-cleaning capacity, yet their visible-light activity and charge recombination remain challenging. In this work, hydrophilic Ag/Ag 3 PO 4 -PDA-n@PES ultrafiltration (UF) membranes were fabricated via polydopamine-assisted surface modification of polyethersulfone (PES) substrates followed by in-situ mineralization of Ag/Ag 3 PO 4 nanoparticles. The membranes were systematically characterized, and the optimized Ag/Ag 3 PO 4 -PDA-5@PES exhibited a water flux of 125 L m −2  h −1 (LMH) and 89.0 % bovine serum albumin (BSA) rejection, outperforming the pristine PES (98 LMH, 66 %). Under visible light, the membrane achieved 87–89 % degradation of organic dyes with a kinetic constant of 0.0254 min −1 for Rhodamine B (RhB), retaining >80 % efficiency after five cycles. In cyclic filtration with RhB, only a 13 % flux decline occurred after three backwashing/self-cleaning cycles, with a flux recovery of 98 %, confirming its strong antifouling and self-cleaning capacity. Moreover, a continuous operation with synthetic urine wastewater achieved 80–95 % chemical oxygen demand (COD) and 90–95 % chroma removal, demonstrating the membrane's practical potential in wastewater treatment.