High-performance thin-layer hydrogel composite membranes for ultrafiltration of natural organic matter

Thin-layer hydrogel composite (TLHC) ultrafiltration (UF) membranes were synthesized by photo-grafting of either poly(ethylene glycol) methacrylate (PEGMA) or N, N-dimethyl-N -(2-methac ryloyloxyethyl- N-(3-sulfo propyl) ammonium betaine (SP E) onto commercial polyethersulfone (PES) UF membranes. The performance of TLHC UF membranes was evaluated for natural organic matter (NOM ) filtration and compared to commercial PES UF membranes. The fouling evaluation was done by investigation of membraneâsolute interactions (adsorptive fouling) and membrane-solute-solute interactions (UF). The results sugg est that the TLHC membranes convincingly displayed a higher adsorp tive fouling resistance than unmodiï¬ed PES UF membranes. In long-term stirred dead-end UF, a much lower fouling was observed for TLHC membranes than for commercial membranes with the same ï¬ux and rejection. Further, water ï¬ux recovery was also much higher. An analysis using an existing blocking model was perf ormed in order to eluci date the effect of a polymer hydrogel layer on fouling mechanism as well as cake layer characteristics. The TLHC membranes synthesize d by photo-g rafting of PEGM A (40 g/L) and PEGMA with a low concentration of cross-linker mon omer in the reaction mixture (ratio: 40/0.4 (g/L)/( g/L))showed a much better performance than the other composite membranes. Those membranes could reduce the cake resistance on the membrane surface. This work has relevance for the design of high-per formance UF membranes for applica tions in water treatmen