Photoinduced hydrophilicity and photocatalytic decomposition of endocrine-disrupting chemical pentachlorophenol on holla
- PDF / 255,734 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 2 Downloads / 148 Views
Mamoru Watanabe, Hiromitsu Nakajima, Masaru Harada, Kenjiro Fujimoto, and Satoshi Awatsu Advanced Materials Laboratory, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan
Yoshio Hasegawa KAKEN Cooperation, Shikada 873-3, Asahi, Kashima, Ibaraki 311-1416, Japan (Received 6 July 2002; accepted 21 November 2002)
Surface properties and photocatalytic oxidation reactions on the hollandite-type compound K2Ga2Sn6O16 (KGSO) were examined for photoinduced hydrophilicity and oxidative decomposition of an endocrine-disrupting chemical, pentachlorophenol (C6Cl5OH, PCP), under ultraviolet (UV) illumination. The thin films and mesoporous powders of hollandite were used for examination of surface properties and photocatalysis, respectively. The photoinduced surface property was examined by measurement of the contact angle of water, ortho-chlorophenol (o-C6H4ClOH), and toluene on the surface of KGSO. The contact angle of H2O and o-C6H4ClOH decreased to 0° under UV illumination. The toluene showed little change in contact angle under UV irradiation. It is concluded that the surface of KGSO shows photoinduced hydrophilicity for H2O and aromatic compounds with hydroxyl groups (–OH). In addition, KGSO clearly showed a photo-oxidative decomposition of PCP under weak UV illumination at room temperature. The decomposition speed of C6Cl5OH on KGSO was much faster than that on previous reported nano-sized SnO2 photocatalysts. It is expected that photo-oxidative decomposition of aromatic compound will be controlled by a combination of optimum composition of the hollandite phase and control of the morphology of the hollandite particles. This suggests that hollandite would be a promising photocatalyst for decomposition of aromatic compounds in endocrine-disrupting chemicals.
I. INTRODUCTION
Endocrine-disrupting chemicals such as pentachlorophenol C6Cl5OH (PCP)1 are hazardous for the generative function of living creatures.2 Social interest has been focused on the health risk assessment of a wide range of chemical toxicities, such as those that interfere with the reproductive systems3–5 and the removal of these compounds from the environment. Photocatalysis presents an effective route for removing these pollutants especially where low concentrations are encountered.6 Most current studies on photocatalysis are related to using titanium dioxide (TiO2);7,8 however, a diversity of photocatalysts a)
Address all correspondence to this author. e-mail: [email protected]
1046
http://journals.cambridge.org
J. Mater. Res., Vol. 18, No. 5, May 2003 Downloaded: 18 Mar 2015
will be required to deal with the increasing number of identified harmful chemicals which occur under a range of different conditions. The authors observed previously that selective reduction of nitric oxide with propylene occurred on thermally activated hollandites.9–11 Mesoporous hollandite powders were also shown to have a high adsorption capacity for nitric oxide and a high selectivity for the reduction under lean burn conditions.
Data Loading...
