Preparation and characterizations of poly(vinylidene fluoride)/oxidized multi-wall carbon nanotube membranes with bi-continuous structure by thermally induced phase separation method

Poly(vinylidene fluoride)/oxidized multi-wall carbon nanotube (PVDF/O-MWCNT) flat membranes with bi-continuous structures were successfully prepared via the thermally induced phase separation (TIPS) method. The effects of O-MWCNT content, PVDF concentration and quenching temperature on the membrane properties were systematically discussed. The results indicate that the membrane structure changes to a denser one and the pure water fluxes (PWFs) of the resultant membranes decline with the increase of O-MWCNT content. With the addition of O-MWCNTs from 0.0 to 0.6 wt%, the BSA rejections of the resultant PVDF/O-MWCNT membranes are improved dramatically. The highest BSA rejection attained is above 90.0%, implying that a novel PVDF/O-MWCNT ultrafiltration membrane is fabricated. The surface hydrophilicity and anti-fouling ability of the membranes are improved with the addition of O-MWCNTs. Furthermore, the mechanical properties of the resultant membranes are enhanced compared with the pristine PVDF membranes. This work demonstrates that O-MWCNTs play a critical role in determining the morphologies and performances of PVDF/O-MWCNT membranes prepared via the TIPS method.