Development of loose thin film nanofibrous composite nanofiltration membrane with modified g-C3N4 nanosheets barrier layer for efficient separation of salt/dye mixtures

• Published in: Separation and purification technology 2023-02, Vol.306, p.122661, Article 122661
• Main Authors: Zhang, Hong, Zhang, Tonghui, Ding, Siping, Wang, Xuefen
• Format: Article
• Language: English
• Subjects: Filtration-assisted interfacial polymerization; g-C3N4 nanosheets; Loose nanofiltration; Salt/dye separation
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2022.122661

•Highly permeable LNF membrane was fabricated by filtration-assisted interfacial polymerization.•The GNs barrier layer endowed the LNF membrane with long-term stability and sustainability.•The GNs barrier layer enables the LNF membrane superior dye degradation ability. To effectively separate salt/dye mixtures from textile wastewater, the development of nanofiltration (NF) membranes with stable and loose structure for high permeability is getting an urgent task. In this study, a novel loose thin film nanofibrous composite NF membrane was fabricated by filtration-assisted interfacial polymerization for dye/salt separation, in which two-dimensional g-C3N4 nanosheets (GNs) modified with polyethylenimine (PEI) were sturdily integrated together via reaction with organic phase trimesoyl chloride (TMC) to form a polyamide (PA) soldered GNs barrier layer onto polyacrylonitrile (PAN) nanofibrous substrate. Benefiting from the inimitable photocatalytic activity of GNs, the organic dyes adhered and accumulated on the membrane surface could be easily cleared up under visible light irradiation for the great recyclability of the composite membrane. The optimized robust GNs composite membrane possessed high water permeability (40.9 L m−2 h−1 bar−1), superior dyes rejections (>94%) for Congo Red, Methyl Blue and Reactive Black 5 and low salt rejections (