Improved photocatalytic performance of (ZnO/TiO₂)-β-CD on decolorization of brilliant green dye under UV light irradiation

Abstract

The photocatalytic activity of modified semiconductor nanocomposite (ZnO/TiO₂)-β-CD system, for decolorization of brilliant green dye has been studied under UV light (λ_max= 365 nm) irradiation and results are compared with the activities of (ZnO/TiO₂), bare ZnO and bare TiO₂. The nanocomposite has been characterized by X-ray diffraction, scanning electron microscopy, UV-vis diffuse reflectance spectroscopy. UV–visible analysis has also been used to confirm the complexation pattern between β-CD and the dye. Various experimental parameters like ZnO:TiO₂ ratio, initial concentration of dye, irradiation time and <i>p</i>H have been investigated. Kinetic results show that the decolorization reaction follows pseudo-first order kinetics. The mineralization of brilliant green has been confirmed by chemical oxygen demand measurements. A suitable reaction mechanism for decolorization of the dye by (ZnO/TiO₂)-β-CD has also been proposed. The present results show that (ZnO/TiO₂)-β-CD system is an efficient and low cost modified photocatalyst for the treatment of waste water from textile industries.