Photocatalytic RGO membrane with carbon nitride nanotube intercalation for enhanced wastewater purification

Graphene oxide (GO) has a great potential to be prepared as the membrane separation material because of its interlayer structure. While, low permeability and fouling issues restrict further applications of GO membrane. In this study, a novel photocatalytic self-cleaning graphene oxide (GO) membrane was synthesized via combination with g-C3N4 nanofillers and polydopamine (PDA). Here, g-C3N4 acted as the roles of expanding the interlayer structure and providing the photocatalytic active sites. The GO composites and corresponding membranes were characterized. A series of membrane separation experiments indicated that due to the intercalation of g-C3N4, a pure water flux (PWF) of RGO/PDA/g-C3N4 composite membrane was 98.72 L·m-2·h-1, which had enhanced 116.87% in comparison to RGO/PDA membrane. Also, the photocatalytic degradation experiments revealed the RGO/PDA/g-C3N4 composite membrane was equipped with a superior photocatalytic degradation capacity towards methylene blue (MB) and rhodamine b (RhB) solutions. Moreover, the RGO/PDA/g-C3N4 composite membrane possessed certain continuous filtration performance with stable rejections towards dyes solutions under light irradiation for 50 min. Meanwhile, due to the assemble of photocatalytic active sites on the GO membrane, it was endowed an excellent recycle performance for 5 cycles with the rejection of 96.5% for MB aqueous solution. Hence, it can be expected that the GO membrane prepared in this study posed a great application potential in wastewater treatment.