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

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.