Study On Ag/tio₂ Photocatalyst Prepared By Photocatalytic Oxidation-reduction Reaction

A novel coupling reaction of photocatalytic oxidation-reduction was designed and developed in this master dissertation.The silver nitrate solution and phenol solution were mixed togrther with TiO₂ catalyst.The effects of the operation conditions and process parameters on the coupling reaction activity of the photocatalytic oxidation-reduction were investigated.Meanwhile,the Ag/TiO₂ photocatalysts were prepared by this coupling reaction.The optimal conditions of the photocatalytic oxidation reaction to phenol solution were studied.The optimal parameters were that the phenol solution concentration was 0.02 g.L^-1,the dosage of TiO₂ catalyst was 0.75 g.L^-1,pH value was 6,the temperature was 298 K and the ultrasonic frequency was 45 KHz,the ultrasonic power was 150 W.Meanwhile,the optimal condition and operation parameters of photocatalytic reduction reaction were also studied.According to the coupling reaction of photocatalytic oxidation-reduction,the photocatalytic oxidation of phenol solution and the photocatalytic reduction of the silver nitrate solution were discussed.The results indicated that the reaction activity in the coupling reaction system exceeded that in the single reaction system.It is because that the oxidation of phenol solution consumes photo-yielding holes and the photo-yielding electrons were drained to reduce silver nitrate solution promptly and efficiently.The optimum reaction parameters and the process condition were that the silver nitrate solution initial concentration was 0.2 g.L^-1,the initial concentration of phenol was 0.02 g.L^-1,the dosage of TiO₂ catalyst was 0.75 g.L^-1,pH value was 6,the temperature was 298 K,and the ultrasonic frequency was 45 KHz,the ultrasonic power was 270 W.The preparation technology and reaction conditions of Ag/TiO₂ photocatalyst prepared by the photocatalytic oxidation-reduction reaction were studied.The effect of the silver nitrate solution initial concentration,the reaction time,the dosage of TiO₂ catalyst,the initial concentration of phenol,pH value and the reaction atmosphere on the photocatalytic degradation rate were investigated.The degradation rate of the composite photocatalyst was carried out in a NDC-type cylinder photo-reactor and the results showed that the optimal conditions were that the silver nitrogen solution initial concentration was 0.02 g.L^-1,the reduction time was 2 h,the dosage of TiO₂ catalyst was 0.75 g.L^-1,the initial concentration of phenol was 0.02 g.L^-1,pH value was 4.0 and the reaction atmosphere was N₂.The results of main parameter,the degradation rate of Ag/TiO₂ photocatalyst prepared by the photocatalytic oxidation-reduction reaction to the phenol solution were studied,respectively.The photocatalytic activity of Ag/TiO₂ was improved greatly.