Hydrogen peroxide treated g-C3N4 as an effective hydrophilic nanosheet for modification of polyethersulfone membranes with enhanced permeability and antifouling characteristics

Abstract In this study, first, graphitic carbon nitride was treated with hydrogen peroxide (abbreviated as H2O2-g-C3N4), then was used as a new hydrophilic nanomaterial in the fabrication of polyethersulfone (PES) mixed matrix membrane (MMM) for improving flux, protein and dye separation efficiency and antifouling properties. The H2O2-g-C3N4 nanosheet was inserted into the doping solution to fabricate PES/H2O2-g-C3N4 nanocomposite membrane with the non-solvent induced phase inversion procedure. The results of the SEM and AFM images and also porosity and contact angle analysis were indicated that the modified membranes with H2O2-g-C3N4 had more porosity, smoother surface and more hydrophilic. Also, the influence of various weight percentage of H2O2-g-C3N4 was investigated systematically on the membrane performance. By blending of H2O2-g-C3N4 nanosheet in the membrane matrix, the permeability was raised from 4.1 (for bare membrane) to 30.1 L m-2 h-1 bar-1. Additionally, the effect of the H2O2-g-C3N4 material on the antifouling features indicated that the flux recover ratio of the H2O2-g-C3N4 MMMs was improved and the resistance parameters were reduced. Also, the effect of the H2O2-g-C3N4 material on the antifouling features indicated that the flux recover ratio of the H2O2-g-C3N4 MMMs was improved and the resistance parameters were reduced. Finally, the dye rejection efficiency of the nanocomposite membranes for Orange II and Reactive Yellow 168 was improved. As a result, it could be mentioned that the mixing low amount of H2O2-g-C3N4 in the membrane structure could significantly improve the membrane flux and antifouling properties without reduction in membrane rejection efficiency.