Title: Mechanism and kinetic model of the oxidative degradation of Rhodamine B dye in aqueous solution by ultrasound-assisted Fenton's process

Authors: Mahjabeen Akram; Sampa Chakrabarti

Addresses: Department of Chemical Engineering, University of Calcutta, 92, Acharya P.C. Road, Kolkata 700009, India ' Department of Chemical Engineering, University of Calcutta, 92, Acharya P.C. Road, Kolkata 700009, India

Abstract: A plausible mechanism for sono-Fenton reaction has been proposed and a kinetic model was developed with verification by experimental data. Degradation of Rhodamine B dye using sono-Fenton process has been investigated. Effects of initial pH, initial dye concentration, dosage of FeSO₄, H₂O₂ and ultrasonic power density were studied. Optimum values were: pH = 3, H₂O₂ = 2.74 × 10^-2 mol/dm³, FeSO₄ = 3.60 × 10^-4 mol/dm³. Maximum 99.57% decolourisation and 69.41% COD reduction were obtained in 30 minutes. Sono-Fenton process was more efficient than dark-Fenton or sonolysis under the same conditions. Decolourisation rate increased with increase in initial dye concentration up to 7.30 × 10^-4 mol/dm³ after which it decreased. Similarly, the maximum decolourisation rate was obtained at 2.74 × 10^-2 mol/dm³ of H₂O₂. Decolourisation increased with increasing FeSO₄ dosage and ultrasonic power density. Initial rate was influenced by initial dye concentration, ultrasonic power density and the initial dosage of H₂O₂ and FeSO₄.

Keywords: kinetics; mechanism; sono-Fenton's process; Rhodamine B dye; wastewater; ultrasonic cavitation; decolourisation; COD removal.

DOI: 10.1504/IJEWM.2022.120641

International Journal of Environment and Waste Management, 2022 Vol.29 No.1, pp.80 - 94

Received: 02 Sep 2019
Accepted: 22 Jan 2020
Published online: 31 Jan 2022 *

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