Title: Kinetics of the TiO₂-catalysed photodegradation of reactofix navy blue 2GFN dye

Authors: Sudhanshu Sharma, S.P. Bansal, K.S. Gupta

Addresses: Atmospheric Chemistry Lab, Department of Chemistry, University of Rajasthan, Jaipur 302 004, Rajasthan, India. ' Atmospheric Chemistry Lab, Department of Chemistry, University of Rajasthan, Jaipur 302 004, Rajasthan, India. ' Atmospheric Chemistry Lab, Department of Chemistry, University of Rajasthan, Jaipur 302 004, Rajasthan, India

Abstract: UV-irradiated TiO₂-catalysed as well as uncatalysed photodegradation of the dye, reactofix navy blue 2GFN, has been studied under various reaction conditions. The kinetics have been followed at 603 nm, the λ_max of the dye, in the visible region. The rate of the reaction depends on [dye] and [O₂], and on [TiO₂] when its concentration is below 0.2 g L^-1. On increasing [TiO₂] beyond 0.2 g L^-1, the rate attains a limiting value. On increasing pH, the rate decreases slightly. At 7.0 pH and 0.2 g L^-1 TiO₂, the photodegradation kinetics is in conformity with the following experimental rate law.

Robs=k2[dye]+k3[dye][O2] +

k8K1K2[dye][O2] ————————————— (1+K2[dye])(1+K1[O2])

here k₂ and k₃ are related to uncatalysed and k₈ to TiO₂ catalysed pathways. The complete decolourisation of the dye is achieved in about 20 minutes.

Keywords: photodegradation; photocatalysis; TiO₂; decolourisation; textile dyes; kinetics; titanium dioxide; wastewater treatment; reactofix navy blue 2GFN dye.

DOI: 10.1504/IJEP.2006.010490

International Journal of Environment and Pollution, 2006 Vol.27 No.1/2/3, pp.147 - 157

Published online: 25 Jul 2006 *

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