Electro-Fenton degradation of synthetic dye mixture: influence of intermediates

J. Environ. Eng. Manage 01/2009; 19:277-282.

ABSTRACT Electro-Fenton process is a potentially useful oxidation process for destroying toxic organic compounds in aqueous medium. In this study, the electro-Fenton degradation of a solution mixture of Malachite Green (MG) and Orange II catalyzed by ferric ions was examined. Results showed that this system could degrade and mineralize the dye mixture. It was shown that absorbance decrease in MG was accelerated in the presence of Orange II, whereas absorbance decrease of Orange II at the same conditions was depressed. This behavior was attributed to generation of hydroquinone-like intermediates from degradation of Orange II that can accelerate Fenton reaction by reduction of Fe 3+ to Fe 2+ ions. GC-MS detection of the products formed in the Orange II electro-Fenton degradation showed the generation of dihydroxynaphthalene compounds that are probably responsible for acceleration of MG degradation.

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