Involvement of chloride anion in photocatalytic process
YANG Shi-ying , CHEN Ying-xu , LOU Li-ping , WU Xiao-na
DOI:
Received ,Revised , Accepted , Available online
Volume 17,2005,Pages 761-765
- Summary
- References
- Related Articles
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(OII) in aqueous TiO2 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 OII. In the presence of 0.50 mol/L Cl-, the rate decreased by 70% for MB while increased 7.5-fold for OII. Furthermore, two bands in the ultraviolet region of OII were rapidly broken down. The proposed mechanism was discussed in detail.
