Fenton-like degradation of 2,4-dichlorophenol using calcium peroxide particles: performance and mechanisms

Abstract

The degradation process of 2,4-dichlorophenol (2,4-DCP) in aqueous solution by a Fenton-like system using calcium peroxide (CaO₂) particles as a source of solid H₂O₂ was investigated. EDTA was added to the system to chelate iron and promote the Fenton-like reaction. The results show that 2,4-DCP can be readily degraded in a CaO₂/EDTA-chelated Fe(II) system. Compared with an H₂O₂/EDTA-chelated Fe(II) system, 2,4-DCP degradation showed a moderate reaction rate owing to the slow dissolution process of the CaO₂ particle. Complicated degradation kinetics were observed and the possible reason was revealed. The initial amount of EDTA chelated iron lost during the Fenton-like reaction was in the range 20–30%. The effects of different reaction parameters, such as initial pH, CaO₂ dosage and amount of EDTA–chelated iron, on 2,4-DCP degradation were studied. According to the identification of dominant reactive species and degradation intermediates, a possible theoretical degradation pathway of 2,4-DCP was proposed.