Anti-pollution polyethersulfone/sulfonated polysulfone (PES/SPSf) membrane with different sulfonation degree by reverse thermally induced phase separation (RTIPS) procedure

ABSTRACT Polyethersulfone/sulfonated polysulfone (PES/SPSf) microfiltration (MF) membranes were fabricated via reverse thermally induced phase separation (RTIPS) method and non-solvent induced phase separation (NIPS) method using N,N-dimethyl acetamide (DMAc) and diethylene glycol (DEG) as solvent and non-solvent, respectively. Attenuated total reflectance Fourier transforminfrared (ATR-FTIR) revealed that SPSf was successfully blended with PES in PES/DMAc/DEG solution system. Membranes with completely sponge-like morphology and uniform porous top surface were prepared by RTIPS method, while dense skin surface and finger-like structure presented in the membranes by NIPS method. In addition, pure water flux and bovine serum albumin (BSA) rejection rate of most membranes fabricated via RTIPS method were higher than that of NIPS method. As for membranes prepared by RTIPS method, pure water flux first increased from 511 to 2,119 L/m 2 h and then decreased to 1,499 and 1,896 L/m 2 h, simultaneously, when the pure water flux reached 2,119 L/m 2 h, the BSA rejection rate could still kept at a high level (70.11%). Furthermore, the water flux recovery ratio of membranes containing SPSf were much higher (>80%) than that of the pure PES membrane (59.21%). These results indicated that the permeability and anti-pollution performance of the PES/SPSf membrane could be enhanced with increasing sulfonation degree of SPSf, moreover, RTIPS method was a superior method for membrane preparation.