Construction of a highly stable g-C3N4/NH2-MIL-88B(Fe)/CD@graphene oxide self-cleaning membrane for dye wastewater separation and degradation

Abstract

A g-C₃N₄/NH₂-MIL-88B(Fe)/CD@GO membrane (M2) was prepared by a simple vacuum filtration method. By embedding a Z-scheme heterojunction composite photocatalyst into graphene oxide (GO) nanosheets, not only can the water molecule transport channel be regulated, but the membrane can also be endowed with photocatalytic activity and membrane fouling is effectively alleviated. The pure water permeation flux of M2 (253.26 L m⁻² h⁻¹ bar⁻¹) was 13 times that of the original GO membrane (18.83 L m⁻² h⁻¹ bar⁻¹). What's more, even after 10 cycles, M2 still maintains excellent separation efficiency and flux. After six cycles, the rejection of Congo Red (CR), Malachite Green (MG) and Rhodamine B (RhB) by M2 was over 95%. At the same time, under the conditions of an extreme pH value and high salt concentration, the rejection of dye remained at the original level after six cycles. Therefore, the novel photocatalytic membrane has excellent separation performance, stability and photocatalytic activity, and can be used as a potential membrane for wastewater purification and environmental protection.