The catalytic oxidation of malachite green by the microwave-Fenton processes

Catalytic oxidation of malachite green using the microwave-Fenton process was investigated. 0% of malachite green de-colorization using the microwave process and 23.5% of malachite green de-colorization using the Fenton process were observed within 5 minutes. In contrast 95.4% of malachite green de-colorization using the microwave-Fenton was observed in 5 minutes. During the microwave-Fenton process, the optimum operating conditions for malachite green de-colorization were found to be 3.40 of initial pH, 0.08 mmol/L of Fe^2 + concentration and 12.5 mmol/L of H₂O₂ concentration. Confirmatory tests were carried out under the optimum conditions and the COD removal rate of 82.0% and the de-colorization rate of 99.0% were observed in 5 minutes. The apparent kinetics equation of −dC/dt = 0.0337 [malachite green]^0.9860[Fe^2 +]^0.8234[H₂O₂]^0.1663 for malachite green de-colorization was calculated, which implied that malachite green was the dominant factor in determining the removal efficiency of malachite green based on microwave-Fenton process.