Graphene oxide-cellulose nanocrystal (GO-CNC) composite functionalized PVDF membrane with improved antifouling performance in MBR: Behavior and mechanism

The graphene oxide-cellulose nanocrystal (GO-CNC) composites were facilely synthesized and used as a novel hydrophilic additive to blend into poly(vinylidene fluoride) (PVDF) microporous membrane aiming at improving the antifouling performance of the resultant GO-CNC/PVDF membrane in MBR. The physicochemical properties of the GO-CNC composite and its functionalized PVDF membrane were investigated in detail by SEM-EDX, FTIR, XRD, water contact angle, zeta potential, permeability and fouling analysis. Results revealed that the hydrophilic GO-CNC composite functionalized PVDF microfiltration membrane exhibited higher wettability, lower protein and polysaccharides adsorption, and higher permeability compared to CNC/PVDF and previously reported GO/PVDF membranes. During long-term operation in MBR, the GO-CNC/PVDF membrane displayed superior antifouling performances with characteristic of less EPS accumulation, higher flux recovery ratio, lower irreversible fouling level and longer cleaning cycle, due to higher hydrophilicity and porosity as well as more negative zeta potential in comparison with the pristine PVDF and CNC/PVDF membranes. It can be expected that as a novel hydrophilic and antifouling additive, GO-CNC composite functionalized membranes would receive more extensive applications in MBR system for wastewater treatment and water reclamation.