fig4

Figure 4. Evaluation of Cu/TiO₂ for the removal of common water pollutants: organic dye, bacteria, and biofilm. (A) Scheme of photocatalytic degradation of RhB dye using Cu/TiO₂; (B) The degradation kinetics of RhB using TiO₂ and Cu/TiO₂; (C) The fitted first-order degradation kinetics of RhB by Cu/TiO₂ under visible light irradiation; (D) The effect of various scavengers on the RhB degradation over 3 h; (E) Scheme of photocatalytic destruction of planktonic E. coli by Cu/TiO₂ NPs under visible light irradiation; (F) E. coli inactivation rates of TiO₂ and Cu/TiO₂ NPs with and without visible light irradiation. Inset: Photographs of bacterial colonies of E. coli treated with TiO₂ and Cu/TiO₂ NPs with and without visible light irradiation over time; (G) The optical and microscope images of the biofilm in the microplate wells after treatment with TiO₂ and Cu/TiO₂ (H) The CV assay showing the remaining biofilm after treatment with TiO₂ and Cu/TiO₂ under 180-min visible light irradiation or in the dark; (I) The biofilm disruption efficacy of TiO₂ and Cu/TiO₂ (scale bars represent standard deviation of nine replicates (n = 9) (mean ± SD); n.s > 0.05; ^**P > 0.05; ^***P > 0.001). RhB: Rhodamine B; NPs: nanoparticles; CV: crystal violet.