Solar Photocatalytic Degradation of Reactive Yellow 81 and Reactive Violet 1 in Aqueous Solution Containing Semiconductor Oxides
A. Giwa, P.O. Nkeonye, K.A. Bello, E.G. Kolawole, A.M.F. Oliveira Campos

Abstract
The textile industry consumes considerable amounts of water during the dyeing and finishing operations. Dyes are extensively used and hence wastewaters discharged in rivers or public sewage treatment plants are highly contaminated. In this work, the photocatalytic decolorization and degradation of two reactive dyes, Reactive Yellow 81 (RY81) and Reactive Violet 1 (RV1) in aqueous solution with TiO2-P25 (Degussa) as photocatalyst in slurry form has been investigated using solar rays. The effects of various parameters such as catalyst loading, pH, and initial concentration of the dye on decolorization and degradation have been determined. Chemical oxygen demand and UV-vis spectrophotometer were used to study the mineralization and degradation of the dyes respectively. The most effective catalyst was Degussa P25, which produced decolouration of 92% for Reactive Yellow 81 (50 mg/L) and 85% for Reactive Violet 1 (50 mg/L) in 20 minutes. The results are thus promising in terms of possible application of sunlight/TiO2 catalysed degradation to coloured waste.

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