Photocatalytic Degradation of Gaseous Formaldehyde Using TiO2 Film

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• 作者：Tetsuro Noguchi ; Akira Fujishima ; Phillip Sawunyama ; and Kazuhito Hashimoto
• 刊名：Environmental Science & Technology
• 出版年：1998
• 出版时间：December 1, 1998
• 年：1998
• 卷：32
• 期：23
• 页码：3831 - 3833
• 全文大小：77K
• 年卷期：v.32,no.23(December 1, 1998)
• ISSN：1520-5851

文摘

The photocatalytic degradation of gaseous formaldehyde-amajor cause of sick building syndrome-was studiedusing a TiO₂ thin film. TiO₂ thin films have many uniquephotoinduced properties, for example, self-cleaning, anti-fouling, and anti-bacterial functions. UV illumination of theTiO₂ thin film placed in a gaseous formaldehyde/airenvironment resulted in the total mineralization offormaldehyde to CO₂ and H₂O. We invoked a Langmuir-Hinshelwood kinetic model to analyze the dependence ofreaction rates on the concentration of formaldehyde. Inaddition, the overall decomposition rate constant forformaldehyde was comparable to that of acetaldehyde (astandard test reactant) for initial concentrations of upto 1000 ppmv. However, the apparent adsorption constantK_app of formaldehyde onto TiO₂ was ca. 2.5 times largerthan that of acetaldehyde. Thus in the low concentrationregime, the reactivity of formaldehyde appeared to begreater than that of acetaldehyde. In like manner, a darkadsorption experiment also showed the high adsorptioncapacity of TiO₂ for formaldehyde. Therefore, we concludethat TiO₂ serves as both a good adsorbent and aphotocatalyst for the elimination of gaseous formaldehyde.