Performance of novel a Ag-n-TiO2/PVC reinforced hollow fiber membrane applied in water purification: in situ antibacterial properties and resistance to biofouling

To improve the anti-biofouling properties of membranes, Ag-embedded nano-sized titanium dioxide (Ag-n-TiO2) particles were utilized as biocidal agents to modify polyvinyl chloride (PVC) membranes. Both Ag-n-TiO2/PVC flat sheet membranes and reinforced hollow fiber membranes were fabricated by a phase inversion method with varying Ag-n-TiO2 particle concentrations. As a result, the hydrophilicity, permeability, and retention capability increased with Ag-n-TiO2 concentrations from 0 to 1.5 wt%. In addition, the in situ antibacterial and anti-formation of biofilm properties of the modified membranes were greatly enhanced in the conventional inhibition zone test, Escherichia coli (E. coli) absorption experiment, fluorescent staining experiment, as well as long-term continuous biofouling test. The best results were obtained for the PVC membrane modified by 1.0 wt% Ag-n-TiO2. The optimized membrane presented not only better permeability and in situ antibacterial properties in the E. coli adhesion test, but also an enhancement in resisting biofilm formation and a more steady permeation flux in long-term filtration than the unmodified membrane.