| Summary: | 碩士 === 國立臺灣師範大學 === 工業教育學系 === 99 === This study investigated the production of titanium dioxide photocatalyst film by electrophoretic deposition (EPD) at constant current, and the practical applications for the degradation of formaldehyde gaseous pollutants. The titanium dioxide powder (Degussa P25), alginate dispersant, and water were used to prepare different concentrations of TiO2/water nanofluids as a working fluid for EPD by a two-step synthesis. Analyzed the physical and chemical characteristics for the different concentrations of TiO2/water nanofluids at different temperatures. In the electrophoretic deposition process, the surface characteristics of the deposited film and the material properties are discussed for the different process parameters of EPD. In photocatalytic experiments of deposited film, the photocatalytic efficiency was measured for the degradation of methylene blue under UVA and visible light irradiation. Finally, a performance test for the degradation of gaseous formaldehyde in the photocatalytic circulation reactor was performed.
The results indicate that the TiO2/water nanofluids change their physical and chemical properties at different temperatures. In deposited film production, using a constant current for the electrophoretic deposition process, the operating current and deposition time can be controlled to obtain a homogenized and smooth deposited film. In the methylene blue degradation experiment, the optimal process parameters for the degradation of methylene blue were those in sample NO.5 /9 mA/5 min under UV irradiation is best（78.40%）. In photocatalyst modification, the optimal parameters for the degradation of methylene blue are modified by LiNO3 (0.1 M) under visible light irradiation is best（35.23%）. In the degradation of formaldehyde gas pollutants, the ambient temperature affects the photocatalytic degradation performance for formaldehyde, and the modification of the photocatalyst by LiNO3 yields the optimal degradation performance for formaldehyde under ultraviolet and visible light irradiation. The successful development of a photocatalytic filter excited by visible light could effectively extend the range of applications in this study.
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