A nanofiltration (NF) membrane containing a NaOH-treated electrospun polyacrylonitrile (HPAN) substrate, an interfacial polymerization (IP) polyamide (PA) layer, a chitosan (CS) coating layer, and an Ag/AgBr/AgVO3 photocatalyst loading layer was prepared. The structural evolution of the membranes was investigated, and their performance was estimated in accordance with the water flux and rejection rate. A probable mechanism for the photocatalytic activity of Ag/AgBr/AgVO3 was proposed. The loading of the Ag/AgBr/AgVO3 heterojunction on the HPAN/PA/CS NF membrane endowed the membrane with excellent self-cleaning properties owing to the photolytic degradation of the dye. The filtration and degradation processes of the Ag/AgBr/AgVO3-loaded membrane constantly promoted each other, and the treatment efficiency achieved with the integrated (filtration + degradation) process was superior to those obtained with the filtration and degradation processes alone. The Ag/AgBr/AgVO3-NF membrane exhibited excellent recyclability and stability when subjected to five integrated filtration-degradation processes. In addition, the Ag/AgBr/AgVO3-NF membrane exhibited an elastic modulus of 65.75 MPa and a toughness of 38.9 kJ/m3 along with a good disinfection effect on Escherichia coli in visible light. The as-prepared photocatalyst-loaded NF membrane with excellent antifouling performance, antimicrobial activity, high strength, and recyclability showed potential for continuous water purification operation.
Keywords: antibacterial activity; antifouling performance; integrated filtration−degradation; nanofiltration membrane; photocatalysis; recyclability.