1. Involvement of chloride anion in photocatalytic process.
- Author
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Shi-ying Yang, Ying-xu Chen, Li-ping Lou, and Xiao-na Wu
- Subjects
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CHLORIDES , *ANIONS , *PHOTOCATALYSIS , *POLLUTANTS , *PHOTODEGRADATION , *METHYLENE blue , *ULTRAVIOLET radiation , *DYES & dyeing , *PHOTOCHEMISTRY - Abstract
The effect of Cl^- on photocatalytic degradation (PCD) of pollutants is an important factor since it is ubiquitous in nature. In general, Cl^- showed an inhibition on photodegradation due to its scavenging HO^{·} radicals. In this paper, experiments were carried out to examine the effects of Cl^- on the PCD of Methylene Blue (MB) and Orange II (Oll) in aqueous TiO_2 suspensions under UV light illumination. It was found that low concentration of Cl^- (< 0.01 mol/L) showed little influence on both dyes, however, high concentration of Cl^- (> 0.10 mol/L) had a very different influence on the decolorization of dyes: a significant inhibition for MB but a great promotion for Oll. In the presence of 0.50 mol/L Cl^-, the rate decreased by 70% for MB while increased 7.5-fold for Oll. Furthermore, two bands in the ultraviolet region of Oll were rapidly broken down. The proposed mechanism was discussed in detail. [ABSTRACT FROM AUTHOR]
- Published
- 2005