Impact of graphitic carbon nitride/polydopamine on permeance and antifouling performance of reverse osmosis membranes

[Display omitted] •A graphite carbon nitride/polydopamine (g-C3N4/PDA) incorporated TFN membrane was fabricated.•The g-C3N4/PDA incorporated TFN had enhanced water permeance and antifouling properties.•The impact of g-C3N4/PDA on membrane preparation, structural variation and performance enhancement was studied. Nanotechnology advancements have significantly contributed to the development of thin-film nanocomposite (TFN) reverse osmosis membranes for addressing global water scarcity through more efficient separation and purification processes. However, the impact of nanomaterials on membrane preparation, structure, and performance remains insufficiently understood. In this study, graphitic carbon nitride/polydopamine (g-C3N4/PDA) incorporated TFN membrane was proposed and systematically investigated through experimental methods and molecular dynamics (MD) simulations. The incorporation of g-C3N4/PDA increased the resistance to MPD diffusion during the interfacial polymerization process, the obtained TFN membrane displayed a thinner, smoother active layer and enhanced hydrophilicity. Therefore, the membrane exhibited a remarkable water flux of 53.43 L·m−2·h−1, triple that of the conventional membrane, with a NaCl rejection of 98.9 %. Meanwhile, the TFN membrane displayed excellent antifouling properties against both organic, inorganic and mixed foulants, maintaining a high flux recovery rate during long-term operation. MD simulation further revealed the stable interaction between g-C3N4/PDA nanocomposites and the polyamide matrix, enhancing structural compatibility and improving membrane performance. This study provides insights into the role of nanomaterials in the active layer of the membrane, offering both theoretical and practical guidance for the design of advanced TFN membranes with enhanced water permeance and antifouling performance.