Preparation and characterization of modified polyethersulfone hollow fiber membranes by blending poly (styrene-alt-maleic anhydride)

In this study, pH-sensitive polyethersulfone (PES) hollow fiber membrane was prepared by blending a copolymer of poly (styrene-alt-maleic anhydride) (PSMA). The PSMA alternating copolymer was synthesized by a traditional synthetic route, and was characterized by Fourier transform infrared spectroscopy (FTIR) analysis, nuclear magnetic resonance (1H NMR) and gel permeation chromatography technique (GPC). The PES/PSMA membrane was then transformed to carboxylic PES/PSMA-H carboxylic membrane using sodium hydroxide solution, by which the anhydride groups were transformed to carboxyl groups, and the modified membranes showed excellent pH-sensitivity and pH-reversibility. Furthermore, the alternating copolymer modified PES hollow fiber membranes showed evident hysteresis of water flux, for which it would take several hours to reach the equilibrium state.

► We prepare an alternating copolymer poly (styrene-alt-maleic anhydride) (PSMA).
► The pH-sensitivity and pH-reversibility are investigated.
► The carboxylic PES/PSMA-H carboxylic membranes show evident hysteresis of water flux.
► Hydrodynamic permeability (km) is almost the same for the two membranes when the feed solution was at alkaline condition; and at acidic condition, the multiple of the permeability is almost the same as the content of the copolymer in the membrane.