Efficient photodegradation of 2,4-dichlorophenol in aqueous solution catalyzed by polydivinylbenzene-supported zinc phthalocyanine

摘要

In this study, photodegradation of 2,4-dichlorophenol (2,4-DCP) in aerated aqueous solution at pH 13 in the presence of hydrogen peroxide catalyzed by polydivinylbenzene-supported zinc phthalocyanine (PDVB-ZnPc) prepared from chloromethylated polydivinylbenzene and zinc phthalocyanine via a Friedel–Crafts reaction has been investigated. The reaction intermediates were identified by gas chromatography–mass spectrometry (GC–MS). The reactive oxygen species involved in the reaction were determined by electron paramagnetic resonance (EPR) technique. Based on the experimental results obtained, PDVB-ZnPc was found to be effective for removing and mineralizing the toxic 2,4-DCP in aqueous solution. The removal yield amounted to 98% after 4 h of irradiation. The reaction followed pseudo-first-order kinetics, and was well fitted into the Langmuir–Hinshelwood-type equation. The optimal concentration of PDVB-ZnPc was 1.0 g/l. The reaction intermediates were some biodegradable organic acids which were subsequently mineralized to CO32- and Cl- in alkaline solution. Hydroxyl radical and superoxide anion radical other than singlet oxygen were probably generated during the photodegradation of 2,4-DCP in our reaction system.