Hydrogen peroxide treated g-CN 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 HO-g-CN), 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 HO-g-CN nanosheet was inserted into the doping solution to fabricate PES/HO-g-CN 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 HO-g-CN had more porosity, smoother surface and more hydrophilic. Also, the influence of various weight percentage of HO-g-CN was investigated systematically on the membrane performance. By blending of HO-g-CN nanosheet in the membrane matrix, the permeability was raised from 4.1 (for bare membrane) to 30.1 L m h bar. Additionally, the effect of the HO-g-CN material on the antifouling features indicated that the flux recover ratio of the HO-g-CN MMMs was improved and the resistance parameters were reduced. Also, the effect of the HO-g-CN material on the antifouling features indicated that the flux recover ratio of the HO-g-CN 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 HO-g-CN in the membrane structure could significantly improve the membrane flux and antifouling properties without reduction in membrane rejection efficiency.