Layer-by-layer self-assembly of polycation/GO nanofiltration membrane with enhanced stability and fouling resistance

Polyelectrolyte multilayering is a good technique used to fabricate nanofiltration (NF) membranes. However, the stability and fouling resistance of the polyelectrolyte membranes should be improved for industrial application. In this study, graphene oxide (GO) nanosheets were assembled with polycation to form a multilayer on a polyacrylonitrile substrate via a layer-by-layer self-assembly strategy. The migration and rearrangement of the polyelectrolyte chain were restricted because of the confinement effect of a neighboring GO nanosheet layer. Therefore, the anti-swelling property of the polycation/GO multilayer membrane was enhanced, which resulted in a more stable performance. The fouling resistance of the multilayer membrane was also improved because of the anti-fouling capability of the GO nanosheets. The polycation/GO multilayer membrane was used to remove dye from water. During the separation of methyl blue molecule from water at 5 bar, the flux and retention rate of the obtained multilayer membrane could reach 6.42 kg m−2 h−1 bar−1 and 99.2%, respectively. Compared with a pure polyelectrolyte multilayer membrane, the separation performance, stability, and fouling resistance of the polycation/GO membranes were significantly enhanced. The polycation/GO multilayer membrane can be potentially used to fabricate NF membranes because it is cost efficient and GO nanosheets can be produced in a large scale.