Degradation of Nile Blue by Photocatalytic, Ultrasonic, Fenton, and Fenton-like Oxidation Processes

Abstract

The aim of this study is to investigate new catalytic systems for the degradation of a dye that has been classified as first-degree toxic pollutant. Advanced oxidation process such as photocatalytic oxidation, ultrasonic oxidation, Fenton, and Fenton-like constitute a promising technology for the treatment of wastewater containing organic compounds. Waste effluents from textile industries are a major source of water pollution. These wastewaters contain dyes, which have high toxicity and low biodegradability. In this study, degradation of Nile Blue (NB), an azo dye, was studied using the photocatalytic oxidation (TiO2 and silver-loaded TiO2 (Ag-TiO2) as catalyst), ultrasonic oxidation, Fenton (Fe(II)/H2O2), and Fenton-like (Cu(II)/H2O2, V(IV)/H2O2) processes. It was found that the photocatalytic degradation of NB increased with decreasing pH, and the degradation rate also increased in the presence of TiO2/UV compared to UV irradiation alone. In addition, Ag loading on TiO2 dramatically reduced the degradation time. The ultrasonic degradation of NB was also studied using different initial dye concentrations at different pH values and amplitudes. Concentrations of Fe(II), Cu(II), V(IV) and H2O2 on degradation ratio were investigated. It is found that Fe(II) ion is more effective than Cu(II) and V(IV) ions in the degradation of NB.