Bactericidal Activity of Photocatalytic Reaction in Aqueous Media by the TiO₂-Coated Stainless Steel Sieves

Thin films with the high content of Ti coated on the stainless steel (SS) sieves were successfully prepared through the sol gel method. Photocatalytic reaction on the TiO₂-coated SS sieves with UVA (ultraviolet light with the range of 315-400 nm) radiation is effective to destroy three selected bacterial strains with log-phase period. As a result, bactericidal ability was achieved to 77% in aqueous media. Amount of bacterial numbers, 3.4×10⁷ CFU/ml can be removed in this study, compared with our previous study, 1.85×10³ CFU/ml in the air media. Good contribution of bactericidal ability in 385 nm UVA radiation or heavy metals including Fe, Mn, Cr, Ni and Ti from the SS sieve was obtained as the range of 30-76%. The percentage of 10-17% contribution of bactericidal ability was increased with the photocatalytic reaction additive. It concluded the performance of bactericidal ability in aqueous solution is ascribed to the combination of UVA radiation, heavy metals on the sieve and photocatalytic reaction. The SS sieve coated with TiO₂ particles can be applied as a disinfectant for the effluent of wastewater treatment plant or water supply system in the future.