Solar Light Induced Degradation of Reactive Dye Using Photocatalysis

Abstract

Outdoors experiment with natural solar light instead of using artificial UV light was also conducted to investigate alternative energy source applicability on organics degradation. The results of this study were as follows. Degradation of the reactive dye, Red 120, with TiO₂/solar light was enhanced by augmentation in TiO₂ loading, and UV light intensity but was inhibited by increase in initial dye concentration. With both solar light illumination and TiO₂ present, reactive dye was more effectively eliminated than with either solar light or TiO₂ alone. Photocatalytic removal efficiency of reactive dye increased with increasing TiO₂ dosage. However, over 1.5 gL⁻¹ of TiO₂ dosage, the efficiency reached a plateau. The degradation rate of reactive dye, Red 120, was strongly dependent on initial dye concentration, and all the experimental data were fit to the first-order rate equation. Photocatalytic degradation of reactive dye increased linearly with increasing UV light intensity. It is found that the presence of thick clouds in the sky markedly increased the time required for degradation of reactive dye. On the basis of these experimental observations, the photo-oxidation degradation of reactive dye using TiO₂ under solar light irradiation can be feasible application of the advanced oxidation process.

Keywords:

• Photocatalytic
• Reactive dye
• TiO₂
• Solar light