Study On Photocatalytic Oxidation Of Indoor Formaldehyde And Sulfur Dioxide By Modified TiO₂Self-cleanins Film

The different varieties of doping modified nanometer TiO2photocatalyst were prepared by adopting sol-gel method, titanium dioxide films were prepared on glass substrates and the best preparation conditions was developed. Choosing the activated carbon as carrier, which has strong adsorption ability and large specific surface area, and the TiO2thin films separately test their photocatalytic efficiency by oxidation of the formaldehyde and sulfur dioxide. Through the examination methods of XRD, EDS, UV and so on, the TiO2photocatalyst has been carried on the microscopic analysis separately. The hydrophobic nature of the films had been characterized by the automatic contact angle meter. The factors, reaction kinetics, reaction mechanism about photocatalytic technology of nano-titanium dioxide for treating the indoor noxious gas pollution were studied by experiments. The experiments were carried out in the new photoreactor which was designed by ourselves. The experimental results showed that after doping modification, the visible-light catalytic activity of TiO2improved, the efficiency of TiO2that vanadium mixed for the formaldehyde could be reached71.3%, and the efficiency of TiO2that nitrogen and vanadium mixed together for the sulfur dioxide reached as high as93.2%. The reaction mechanism included two process, adsorption and photocatalytic oxidation, through the analysis of the oxidation product together with the catalyst characterized, and the photocatalytic oxidation played a leading role. It existed competition adsorption between the gas mixture in the reaction through the treatment of the gas mixture, the SO2had a big influence on the formaldehyde, and the influence on N-V-TiO2was smaller than V-TiO2. Dealing with the data, it indicated that the catalytic response dynamics of nanometer TiO2to formaldehyde accorded with the law of the first grade reaction, the reaction rate was about0.257mg/m3·min. The TiO2films had good hydrophobic nature and degradation efficiency, their contact angle could be greater than130°. The results provided the reference and maybe helpful for further application.