Preparation and characterization of polyethersulfone/N-phthaloyl-chitosan ultrafiltration membrane with antifouling property

In order to reduce fouling, membranes are modified by several techniques, among them, blending with hydrophilic additives are the most practical. N-phthaloyl-chitosan (NPhthCs) was obtained by the reaction of chitosan with phthalic anhydride in dimethylformamide and used as additive in the casting solution. Polyethersulfone (PES) membranes without and with NPhthCs were prepared by phase inversion via immersion precipitation. Modified membranes showed higher hydraulic permeance (27 +/- 4 L m(-2) h(-1) bar(-1)) and hydrophilicity by contact angle (CA) measurement (CA = 56 +/- 5 degrees) than pure PES membranes. In bovine serum albumin (BSA) membrane filtration experiments, PES/NPhthCs membranes showed higher permeate fluxes, but the relative flux loss and recovery and also the BSA retention (90 +/- 2% PES and 86 +/- 10% PES/NPhthCs membranes) were not significantly different. Resistance-in-series analysis showed that both concentration polarization and fouling resistances were significantly lower for PES/NPhthCs membranes, indicating that the chemical modification improved the antifouling property of these membranes.