Hydrogen peroxide generation and capillary electrophoresis for electro-Fenton oxidation

J. Environ. Eng. Manage 01/2009; 19:307-314.


Optimum conditions for generating hydrogen peroxide in Electro-Fenton oxidation in an undivided cell at a carbon cloth cathode were individuated, examining the effect of cathode potential, technique for providing oxygen, pH and concentration of electrolyte. The best conditions are: cathode potential -1 V vs. Ag/AgCl, air sparing 1 L min -1 at the cathode, pH 3.0 in 0.05 M sodium sulphate electrolyte. Capillary electrophoresis was investigated as a potential analytical technique for monitoring electro-Fenton oxidation of chlorinated anilines by determining the inorganic ions produced. The sequential analysis of the six ionic species investigated required less than 1 h on a routine basis. In the electro-Fenton oxidation of chloroanilines, stoichiometric amounts of ammonium and chloride ions were measured after 180-min treatment; no nitrite or nitrate ions were detected. Fe 2+ was continuously regenerated at the cathode and the observed time trends of Fe 2+ and Fe 3+ concentrations showed marked differences in the presence or absence of chloroanilines.

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    ABSTRACT: This study was designed to investigate the oxidation (decolorization/degradation) of Sunset Yellow FCF azo-dye (which is largely used as colorant in common foods and drugs industries) in aqueous solutions with electro-generated Fenton's reagent (H2O2/Fe2+). This has been carried out at room temperature in an undivided electrochemical reactor of a RVC cathode and a platinum gauze anode. The progress of oxidation of Sunset Yellow FCF azo-dye by electro-generated Fenton's reagent has been monitored by UV–visible absorption, chemical oxygen demand (COD) and HPLC measurements. The results obtained under the optimal operational parameters (0.05 M Na2SO4 aqueous solution of pH 3 containing 0.1 mM FeSO4 while controlling the RVC cathode applied potential at − 1.0 V vs. SCE) showed that complete decolorization (100%) and significant mineralization (approximately 97%) of Sunset Yellow FCF azo-dye have been achieved by electro-Fenton oxidation for 120 min. The rate of the oxidation reaction of Sunset Yellow FCF azo-dye in aqueous solution by electro-generated Fenton's reagent has been found to fit to pseudo first-order kinetics.Research highlights► Oxidation of Sunset Yellow until significant mineralization was achieved. ► Results indicated complete decolorization and destruction of aromatic rings. ► Rate of oxidation by electro-Fenton's reagent fits pseudo first-order kinetics.
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