Improvement of Permeation Performance of Polyethersulfone (PES) Ultrafiltration Membranes via Addition of Tween-20

In this study, effects of Tween-20 (polyoxyethylene sorbitan monolaurate) as a variable surfactant additive on morphology, permeation performance and antifouling properties of asymmetric polyethersulfone (PES) membranes were investigated. The membranes prepared from PES/polyethylene glycol (PEG)/N,N-dimethyl-formamide (DMF) system via phase inversion induced by immersion precipitation in water coagulation bath. The membranes performances were evaluated using ultrafiltration (UF) experiments. The scanning electron microscope and atomic force microscopy analysis were performed to investigate the membrane morphology. The obtained results indicate that by increasing the concentration of Tween-20, the membrane morphology changes slowly from thin finger-like structure with spongy structure to long and wide finger-like structure with some macrovoids. Addition of surfactant to the casting solution increases the porosity of the membrane sublayer. It was found out that the rejection ratio of Bovine serum albumin (BSA) decreases, while the flux recovery ratio remarkably increases and the degree of irreversible fouling decreases. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 504-513, 2010