International Journal of Photoenergy 
Volume 2008 (2008), Article ID 978329, 7 pages
doi:10.1155/2008/978329
Research Article

Photocatalytic Degradation of a Water Soluble Herbicide by Pure and Noble Metal Deposited TiO2 Nanocrystalline Films

Katerina Pelentridou,1 Elias Stathatos,2 Helen Karasali,3 Dionysios D. Dionysiou,4 and Panagiotis Lianos1

 1Engineering Science Department, University of Patras, 26500 Patras, Greece
2Electrical Engineering Department, Technological-Educational Institute of Patras, 26334 Patras, Greece
3Benaki Phytopathological Institute, Pesticide control and Phytopharmacy, 14561 Athens, Greece
4Department of Civil and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221-0071, USA
Received 1 April 2008; Revised 12 May 2008; Accepted 5 July 2008

Recommended by Jean-Marie Herrmann

Abstract

We present the photocatalytic degradation of a water soluble sulfonylurea herbicide: azimsulfuron in the presence of titania nanocrystalline films. Efficient photodegradation of herbicide was achieved by using low-intensity black light tubes emitting in the Near-UV. The degradation of the herbicide follows first-order kinetics according to the Langmuir-Hinshelwood model. Intermediate products were identified by the LC-MS-MS technique during photocatalytic degradation. In order to increase photodegradation rate of the herbicide, we examined the effect of titania modification by depositing noble metals at various quantities and valence states. The presence of platinum at neutral valence state and optimum concentration induced higher photodegradation rates while silver-modified titania exhibited similar photocatalytic rates with those obtained with pure nanocrystalline TiO2 films. Finally, the effect of initial pH value was also examined. Acidic or alkaline media were unfavorable for azimsulfuron photodegradation.