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International Journal of Photoenergy
Volume 2012, Article ID 874509, 8 pages
http://dx.doi.org/10.1155/2012/874509
Research Article

Fabrication of Al-Doped TiO2 Visible-Light Photocatalyst for Low-Concentration Mercury Removal

1Graduate Institute of Engineering Science and Technology, National Kaohsiung First University of Science and Technology, No. 2 Jhuoyue Road, Nanzih, Kaohsiung 811, Taiwan
2Department of Environmental, Safety, and Health Engineering, Tungnan University, Section 3, 152, Peishen Road, Shenkeng, New Taipei 222, Taiwan
3Institute of Environmental Engineering and Management, National Taipei University of Technology, Section 3, No. 1, Chung-Hsiao E. Road, Taipei 106, Taiwan

Received 13 September 2011; Revised 30 December 2011; Accepted 31 December 2011

Academic Editor: Gongxuan Lu

Copyright © 2012 Cheng-Yen Tsai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

High-quality Al-doped TiO2 visible-light photocatalyst was prepared via a single-step direct combination of vaporized Ti, Al, and O2 using a 6 kW thermal plasma system. Results showed that the formed Al-doped TiO2 nanoparticles were a mixture of anatase and rutile phase and had a size between 10 and 105 nm. The absorption spectra of the nanoparticles shifted towards the visible light regions, depending on the Al2O3 addition. Ti4+ and Ti3+ coexisted in the synthesized Al-doped TiO2; the Ti3+ concentration, however, increased with increasing Al2O3 addition due to Al/Ti substitution that caused the occurrence of oxygen vacancy. Hg0 breakthrough tests revealed that the nanoparticles had an appreciable Hg0 removal under visible-light irradiation. Nevertheless, moisture reduced Hg removal by the nanoparticles, especially when visible-light irradiation was applied, suggesting that the competitive adsorption between H2O and Hg species on the active sites of TiO2 surface occurred.