| Summary: | 碩士 === 萬能科技大學 === 工程科技研究所 === 95 === This study evaluated the photocatalytic degradation performance of TiO2 supported by Na-Y zeolite with different loading contents and the titanate nanotubes (TNT) prepared via a hydrothermal treatment of TiO2 powders (P25) in a 10 M NaOH solution at 150 oC for 24 h and subsequently washed with HCl aqueous solution of different concentrations (0.1, 0.01, and 0.001 N), using the photocatalytic oxidation of basic dye, Basic Violet 10 (BV10), in aqueous solution.
For the former, the physical and chemical states of zeolite-supported TiO2 were evaluated via powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), and nitrogen adsorption-desorption isotherms. The effects of some operational parameters, including TiO2 content, calcination temperature, pH value, initial dye concentration, and catalyst dosage, on the photocatalytic degradation performance were examined. The results showed that the photocatalytic reaction followed the first-order kinetics for all catalysts. Moreover, it was found that higher TiO2 content (20 wt.% TiO2), calcination temperature (600 oC), pH values (9-10), and catalyst dosage (5333 ppm), as well as smaller initial dye concentration (10 ppm), might induce a better photodegradation efficiency.
For the latter, TNT samples with different contents of remnant sodium in nanotubes were characterized, as synthesized and after heat-treatment, by transmission electron microscopy, X-ray diffraction, and nitrogen adsorption–desorption isotherms. It was found that if the sodium was not completely exchanged with proton, the removal of sodium increased the specific surface area (and pore volume), while the thermal stability was reduced. When the sodium content of TNT was approximately 0 wt.% (nearly complete proton exchange), the nanotubular structure of titanates might be destroyed. The effects of the alterations of microstructures induced by the exchange of sodium and heat-treatment on the photocatalytic activity of TNT were discussed with the variations of specific surface area, pore volume, and the amounts of anatase phase in TNT.
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