Sulfonated poly(α,β,β-trifluorostyrene)-doped PVDF ultrafiltration membrane with enhanced hydrophilicity and antifouling property

Abstract

While polyvinylidene fluoride (PVDF) is widely used as a commercial UF membrane material, PVDF membrane often encounters fouling problems which significantly reduce the separation performance and service life of membrane. In this work, a special fluoro-contained polymer, sulfonated poly(α,β,β-trifluorostyrene) (SPTFS), is used to improve the hydrophilicity of PVDF membrane, thus to enhance the water flux and antifouling property of the membrane. PVDF membranes with different doping amount of SPTFS are prepared through conventional non-solvent induced phase separation method. Effects of doping SPTFS on the surface morphology, porosity, water contact angle and zeta potential of the prepared membranes are investigated. Compared with the pristine PVDF membrane, the SPTFS-doped membranes show improved hydrophilic property with enlarged finger-like pore structure, decreased water contact angle and higher negative surface charge density, as well as the increased filtration water flux. The enhanced anti-fouling property of the membrane is demonstrated by the cyclic filtration test and the in-situ monitoring of the adsorption and desorption of pollutants using a quartz crystal microbalance.