Degradation of 4-Chlorophenol by Means of Fenton Oxidation Processes: Mechanism and Kinetics

Abstract

Stopped-flow technology and HPLC analysis were used to study the degradation mechanism and reaction kinetics of 4-chlorophenol (4-CP) in Fenton oxidation process. The results indicated that benzoquinone and hydroquinone were simultaneously produced in process of Fenton oxidizing 4-CP by stopped-flow technology analysis. The data obtained by HPLC showed that hydroquinone was generated in great quantities following the decrease of benzoquinone. It could be inferred by batch experiments that benzoquinone would be transformed into hydroquinone in Fenton process and hydroperoxyl radical (HO2·) would take the main part in this process. In our study, there would exist two catalytic systems in Fenton process, and one was Fe2+and Fe3+, the other was hydroquinone and benzoquinone. Moreover, the rate constants of hydroquinone, benzoquinone, and 4-chlorocatechol were 2.78 × 106 L s−1 mol−1, 9.38 × 108 L s−1 mol−1, and 6.47 × 106 L s−1 mol−1, respectively.