Accessing of graphene oxide (GO) nanofiltration membranes for microbial and fouling resistance

GO is of great interesting for membrane materials due to its unique properties including antimicrobial activity and antifouling property. However, the differences between GO nanosheets and layered GO membranes gained little attention. Herein, we fabricated GO membranes that have a thickness of around 30 nm and a void d-spacing of 0.67 nm (wet state) with single layer GO nanosheets of 10-75 nm in lateral size and investigated their antimicrobial and antifouling potential for practical use. It exhibits typical nanofiltration performance, with the rejections of 65.23%, 17.79%, 42.10% and 12.47% to Na2SO4, NaCl, Mg2SO4 and MgCl2, respectively. The antimicrobial test demonstrated that GO nanosheets lose their antimicrobial activity after they stacked together. A 14-day test showing that GO membrane has excellent resistance for organic fouling, with reversible fouling of more than 98%. But when it comes to tapwater, the proportion of irreversible fouling is surging to more than fifty percent even after cleaning with 2000 mg/L of sodium hypochlorite. Thus, we suggested that there are more details should be investigated before put layered GO membrane into practical use. Surprisingly, GO membrane exhibits excellent mechanical stability during the 14-day test, showing its exciting potential in water treatment.