Titanium dioxide nanotubes(TNTs)were prepared and used as catalysts for degradation of humic acid by titanium dioxide nanotubes/UV/O3.With a view of kinetics,the effect of calcination temperature and the synergistic e...Titanium dioxide nanotubes(TNTs)were prepared and used as catalysts for degradation of humic acid by titanium dioxide nanotubes/UV/O3.With a view of kinetics,the effect of calcination temperature and the synergistic effect of photocatalysis and ozonation were analyzed.The influences of reaction temperature,original pH value,dosage of TNTs and dosage of ozone on the reaction kinetics were also investigated,and the reaction kinetics model was established.The result showed that photocatalysis and ozonation had a good synergistic effect and the best reaction temperature of TNTs was 400℃.The TOC removal of humic acid followed zero-order kinetics.In the model,the best reaction kinetics k was obtained under the condition with original pH value of 7.35,TNTs dosage of 0.806 g·L-1 and ozone dosage of 0.49 g·h-1.It was 0.8095 mg·L-1·min-1 when the reaction temperature was 25℃ while 0.8231 mg·L-1·min-1 at 30℃.The theoretical predictions were in good agreement with the experimental data.展开更多
The influence of calcination temperature on TiO2 nanotubes＇ catalysis for TiO2/UV/03 was investigated. TiO2 nanotubes （TNTs） were prepared via the sol-gel method and calcined at 300--700 ℃, which were labeled as T...The influence of calcination temperature on TiO2 nanotubes＇ catalysis for TiO2/UV/03 was investigated. TiO2 nanotubes （TNTs） were prepared via the sol-gel method and calcined at 300--700 ℃, which were labeled as TNTs-300, TNTs-400, TNTs-500, TNTs-600 and TNTs-700, respectively. TNTs were characterized by transmission electron microscopy （TEM） and X-ray diffraction （XRD）. It is found that TNTs calcined at 400 ℃ showed the best thermal stability. When the calcination temperature increased from 400 ℃ to 700 ℃, the special structure of tubes was destroyed and gradually converted into nanorods and/or particles. The transformation from anatase to rutile occurred at 600 ℃, and the rutile phase was enhanced when the calcination temperature was increased to over 600 ℃. The calcina- tion temperature＇s influence on TNTs＇ adsorption activity for for TiO2/UV/O3 was investigated in landfill leachate solution chemical oxygen demand （COD） and catalytic activity In landfill leachate solution, the adsorption activity of COD decreased in the reduced order of TNTs-300, TNTs-400, TNTs-500, TNTs-600 and TNTs-700. In photocatalytic ozonation, TNTs-400 showed the best catalytic activity while TNTs-700 exhibited the worst. In other three processes, the COD removal of TNTs-300/UV/O3 was higher than those of TNTs-500/UV/O3 and TNTs-600/UV/O3 in the first 20 rain, and then became close to those of the latter two in the following 40 rain. Compared with TNTs-300 and TNTs- 400, TNTs-600 had the best anti-fouling activity, while TNTs-500 and TNTs-700 had lower anti-fouling activity than the former three. In photocatalytic ozonation, the calcination temperature of 400 ℃ was appropriate when TNTs were obtained at the synthesis temperature of 105 ℃.展开更多
文摘Titanium dioxide nanotubes(TNTs)were prepared and used as catalysts for degradation of humic acid by titanium dioxide nanotubes/UV/O3.With a view of kinetics,the effect of calcination temperature and the synergistic effect of photocatalysis and ozonation were analyzed.The influences of reaction temperature,original pH value,dosage of TNTs and dosage of ozone on the reaction kinetics were also investigated,and the reaction kinetics model was established.The result showed that photocatalysis and ozonation had a good synergistic effect and the best reaction temperature of TNTs was 400℃.The TOC removal of humic acid followed zero-order kinetics.In the model,the best reaction kinetics k was obtained under the condition with original pH value of 7.35,TNTs dosage of 0.806 g·L-1 and ozone dosage of 0.49 g·h-1.It was 0.8095 mg·L-1·min-1 when the reaction temperature was 25℃ while 0.8231 mg·L-1·min-1 at 30℃.The theoretical predictions were in good agreement with the experimental data.
基金Supported by Tianjin Science and Technology Development Plan Project (No.06YFGZSH06700)
文摘The influence of calcination temperature on TiO2 nanotubes＇ catalysis for TiO2/UV/03 was investigated. TiO2 nanotubes （TNTs） were prepared via the sol-gel method and calcined at 300--700 ℃, which were labeled as TNTs-300, TNTs-400, TNTs-500, TNTs-600 and TNTs-700, respectively. TNTs were characterized by transmission electron microscopy （TEM） and X-ray diffraction （XRD）. It is found that TNTs calcined at 400 ℃ showed the best thermal stability. When the calcination temperature increased from 400 ℃ to 700 ℃, the special structure of tubes was destroyed and gradually converted into nanorods and/or particles. The transformation from anatase to rutile occurred at 600 ℃, and the rutile phase was enhanced when the calcination temperature was increased to over 600 ℃. The calcina- tion temperature＇s influence on TNTs＇ adsorption activity for for TiO2/UV/O3 was investigated in landfill leachate solution chemical oxygen demand （COD） and catalytic activity In landfill leachate solution, the adsorption activity of COD decreased in the reduced order of TNTs-300, TNTs-400, TNTs-500, TNTs-600 and TNTs-700. In photocatalytic ozonation, TNTs-400 showed the best catalytic activity while TNTs-700 exhibited the worst. In other three processes, the COD removal of TNTs-300/UV/O3 was higher than those of TNTs-500/UV/O3 and TNTs-600/UV/O3 in the first 20 rain, and then became close to those of the latter two in the following 40 rain. Compared with TNTs-300 and TNTs- 400, TNTs-600 had the best anti-fouling activity, while TNTs-500 and TNTs-700 had lower anti-fouling activity than the former three. In photocatalytic ozonation, the calcination temperature of 400 ℃ was appropriate when TNTs were obtained at the synthesis temperature of 105 ℃.
