Photocatalytic decolorization kinetics of diazo dye Congo Red aqueous solution by UV/TiO2 nanoparticles

The efficiency of color removal from aqueous Congo Red dye (CR) solution has been investigated in TiO2 suspensions irradiated with artificial UV light. Batch photocatalytic tests were carried out by varying the amount of TiO2 and the irradiation time using the same initial CR concentration. The experimental results indicated that the decolorization rate follows pseudo first-order kinetics with respect to CR concentration. The doses of TiO2 were 0.25, 0.5 and 1.0 g L-1 and the wavelength of incident ultraviolet light was predominantly 254 nm. CR adsorption on the surface of TiO2 is also investigated and described.