Floating TiO₂ photocatalyst for efficient inactivation of E. coli and decomposition of methylene blue solution

The anatase phase TiO₂ films with nanocrystalline structure were successfully deposited on a water-floating non-expanded polystyrene (PS) beads via magnetron sputtering. The combination of UVB light and PS beads with TiO₂ film was used for decomposition of methylene blue as well as inactivation tests for intact and EDTA-treated Escherichia coli bacteria. Crystal structure, elemental composition, elemental mapping, surface morphology and chemical bonds of TiO₂ film were investigated. E. coli inactivation experiments showed that such floating photocatalyst could destroy >90% bacteria in 45 min under UVB irradiation. Results demonstrated that combination of TiO₂ and UVB light leads to disruption of the outer membrane which causes effective inactivation of E. coli bacteria.