Degradation of rhodamine dye using a modified flow photocatalytic reactor in the presence of external oxidants

Abstract

The current work addresses the challenge of effectively degrading Rhodamine B dye, a common environmental pollutant using a modified zig-zag flow type photocatalytic reactor with the main objective of process intensification. A detailed study into the effect of initial dye concentration and operating solution pH on the degradation of Rhodamine B elucidated that the Rh B dye degradation was higher at a lower solution pH (pH 2) and at an optimum initial (20 ppm) dye concentration. Among different photocatalysts studied including TiO₂, ZnO, and CaO, maximum degradation was seen for the TiO₂ with 83.3% at optimum loading of TiO₂ (1 g/L). Lower degradations of 76.2% at 1.5 g/L of ZnO and 65.9% at 1.5 g/L of CaO were seen for other photocatalysts. Additionally, the introduction of oxidants such as hydrogen peroxide and Fenton reagent further intensified dye degradation, with the combined UV/Fenton process achieving maximum degradation of 94.8% and the highest COD removal of 68.4%. Overall, it is recommended to utilize zig-zag flow design photocatalytic reactor with combined Fenton's reagent for optimal dye degradation.