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International Journal of Photoenergy
Volume 2012, Article ID 626759, 8 pages
Research Article

Photocatalytic Degradation of Organic Dyes under Visible Light on N-Doped Photocatalysts

1Department of Industrial Engineering, University of Salerno, Via Ponte Don Melillo, Salerno, 84084 Fisciano, Italy
2Department of Chemical Engineering, University of Rome “La Sapienza”, Via Eudossiana 18, 00184 Rome, Italy

Received 4 August 2012; Revised 5 September 2012; Accepted 12 September 2012

Academic Editor: Jiaguo Yu

Copyright © 2012 Olga Sacco 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.


This study was focused on the application of white and blue light emitting diodes (LEDs) as sources for the photocatalytic degradation of organic dyes in liquid phase with visible light. The photocatalytic activity of N-doped titanium dioxide, synthesized by direct hydrolysis of titanium tetraisopropoxide with ammonia, was evaluated by means of a batch photoreactor. The bandgap energy of titanium dioxide was moved in the visible range from 3.3 eV to 2.5 eV. The visible light responsive photocatalysts showed remarkably effective activity in decolorization process and in the removal of total organic carbon. Methylene blue was also used as a model dye to study the influence of several parameters such as catalyst weight and initial concentration. The effect of dye on the photocatalytic performance was verified with methyl orange (MO). The results demonstrated that the right selection of operating conditions allows to effectively degrade different dyes with the N-doped TiO2 photocatalysts irradiated with visible light emitted by LEDs.