Investigation of photocatalytic and visible light self-cleaning performance of 2D/2D g-C3N4-ZrO2 based PES/PDA membranes for organic contaminants degradation

Abstract

This study fabricated a novel photocatalytic, self-cleaning membrane by depositing a 2D-2D g-C3N4/ZrO2 photocatalyst on polydopamine-coated polyethersulfone. The morphologies and surface chemistry of the membranes were studied through FESEM-EDX, AFM, and XPS. The results showed the satisfactory binding stability of the photocatalyst on the polyethersulfone/polydopamine. Also, depositing of the photocatalyst on the polyethersulfone/polydopamine strongly enhanced hydrophilicity. The optimized photocatalytic membrane (39.68 Lm2h) had a substantially higher water flux than polyethersulfone (13.61 Lm2h) and polyethersulfone/polydopamine (19.42 Lm2h). The photocatalytic membranes showed high dye removal and protein rejection rates. The flux recovery ratio was 83.32 % after 30 min of visible-light exposure. The conversion of irreversible contaminants into reversible ones under visible-light demonstrated the self-cleaning nature of the membrane. In addition, the photocatalytic membrane showed substantial stability in the vibration and shear force tests. Therefore, the polyethersulfone/polydopamine/(g-C3N4/ZrO2) membrane is a promising candidate for removing organic contaminants from water due to high rejection, water flux rate, and satisfactory stability. This study not only proposed an efficient methodology to fabricate a novel photocatalytic self-cleaning membrane with high stability but also provided further insights into the effects of the 2D structure of photocatalyst on the flux and photocatalytic degradation performance of such membranes.