Electro-Fenton oxidation of Sunset Yellow FCF azo-dye in aqueous solutions

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.