Evaluation of self-cleaning performance of the modified g-C3N4 and GO based PVDF membrane toward oil-in-water separation under visible-light

Photocatalytic membranes (PMs), coupling of membrane filtration and photocatalysis , have exhibited the potential for application in the wastewater treatment . In this study, we firstly adopted the supramolecular aggregates of melamine (M), cyanuric acid (C), and urea (U) in specific dimethyl sulfoxide (DMSO) as precursors to prepare carbon nitride MCU-C 3 N 4 with high photocatalytic performance, and a kind of novel-designed photocatalytic membrane was prepared via filtrating the mixture of graphene oxide (GO) nanosheets and MCU-C 3 N 4 on PVDF membrane supports, and then crosslinked using glutaraldehyde (GA) to construct a steady coating on the GO/MCU-C 3 N 4 /PVDF membrane. GO/MCU-C 3 N 4 /PVDF composite membrane exhibited higher permeation flux than that of GO/PVDF membrane and exhibited excellent separation performance for oil-in-water emulsion. A visible light-driven self-cleaning four-stage filtration by a self-built dead-end filtration system was carried out to evaluate membrane antifouling property, and GO/MCU-C 3 N 4 /PVDF membrane (M2) possessed higher flux recovery ratio (FRR) (∼92.36%) and lower irreversible fouling resistance (R ir ) ratio (∼8%) under 30min visible-light irradiation, maintaining relatively higher FRR (>72%) during 4 cycling of four-stage filtrating experiments. GO/MCU-C 3 N 4 /PVDF PMs are equipped with high permeation flux, separation performance, anti-fouling property and stability, indicating potential application in water treatment .