Papers by Author: Cheng Che Chiang

Abstract: Magnetic photocatalystic particles (MPCs) become an alternative process for water and wastewater treatment due to the high removal rate of organic pollutants and a good recovery. Little information of MPCs on the control of microorganisms was obtained in previous researches. In this study, the synthesized MPCs combined with 365 nm UVA irradiation under a light of 1.0 mW/cm² were applied to control a typical gram-negative strain Staphylococcus sciuri (99% Identified by the NCBI website), which was isolated from an indoor traditional market in the middle area of Taiwan. As a result, the highest bactericidal efficiency (BE) of MPCs contained 0.50 g magnetic particles in nutrient broth was achieved to 68.18% at 50 mins. Considering to each contribution of bacterial control, UVA irradiation played an important role of BE increased from 34.88% at 10 mins to 63.64% at 50 mins. Photocatalystic reaction provided extra more 11.02% of BE at initial 20 mins. The synthesized MPCs demonstrated good crystallinity of anatase by SEM-EDS and XRF. The 76% MPCs can be recovered by simple magnets after photocatalystic reaction.

Abstract: 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.