Nano-titania/polyethersulfone composite ultrafiltration membranes with optimized antifouling capacity

Abstract

TiO2 nanoparticles synthesized via the sol–gel technique were used as an antifouling additive to produce polyethersulfone membranes by the isothermal immersion–precipitation method. In order to finely disperse the TiO2 in the dope, the sol–gel process for their formation involved DMAc as the solvent, same as that used for preparing the dopes. The pore size, water flux, tensile strength, and molecular weight cut-off of the membranes, as affected by the added amounts of TiO2 sol in the dope, exhibited an increase-then-decrease trend. All membranes demonstrated high rejections (≥ 92.3%) on filtration against BSA aqueous solutions. In the optimal case, nearly perfect rejection at the permeation flux of 91 LMH/bar was achieved for the membrane containing 1.68 wt% TiO2. This membrane also possessed the highest water flux (181 LMH/bar) and antifouling capability among all prepared membranes; specifically, the flux recovery ratio value remained as high as 94% even after three cycles of filtration-cleaning tests.