Advanced oxidation of Reactive Blue 181 solution: A comparison between Fenton and Sono-Fenton Process

In this work, the decolorization of C.I. Reactive Blue 181 (RB181), an anthraquinone dye, by Ultrasound and Fe²⁺ H₂O₂ processes was investigated. The effects of operating parameters, such as Fe²⁺ dosage, H₂O₂ dosage, pH value, reaction time and temperature were examined. Process optimisation pH, ferrous ion (Fe²⁺), hydrogen peroxide (H₂O₂), and reaction time], kinetic studies and their comparison were carried out for both of the processes. The Sono-Fenton process was performed by indirect sonication in an ultrasonic water bath, which was operated at a fixed 35-kHz frequency. The optimum conditions were determined as Fe²⁺] = 30 mg/L, H₂O₂] = 50 mg/L and pH = 3 for the Fenton process and Fe²⁺] = 10 mg/L, H₂O₂] = 40 mg/L and pH = 3 for the Sono-Fenton process. The colour removals were 88% and 93.5% by the Fenton and Sono-Fenton processes, respectively. The highest decolorization was achieved by the Sono-Fenton process because of the production of some oxidising agents as a result of sonication. The paper also discussed kinetic parameters. The decolorization kinetic of RB181 followed pseudo-second-order reaction (Fenton study) and Behnajady kinetics (Sono-Fenton study).