Photodestruction and COD removal of toxic dye erioglaucine by TiO2-UV process: influence of operational parameters

Aqueous solutions of Erioglaucine, a hazardous dye, are photodegraded under ultraviolet light using TiO2 as catalyst. The process has been carried out at different pHs, amounts of catalyst, concentrations of the dye, and effects of the electron acceptor H2O2. It is found that under the influence of TiO2 as catalyst the coloured solution of the dye Erioglaucine becomes colourless and the process follows first-order reaction kinetics. The optimum conditions for the degradation of the dye have been found as 7.0 x 10(-5) M dye concentration, pH 8.5, and 12 mg catalyst dose. In order to evaluate the effect of the electron acceptor, the effect of H2O2 on the degradation process is also monitored and it is found that generation of hydroxyl radicals and retardation of electron-hole recombination takes place. It was observed that photocatalytic degradation by TiO2 is an effective, economic and faster mode of removing Erioglaucine from aqueous solution. Chemical oxygen demand and dye absorbance of the photodegraded dye solution substantially decreased. The adsorption trends of Erioglaucine at various initial concentrations followed the Langmuir isotherm trend.