Optimization of electro-Fenton/BDD process for decolorization of a model azo dye wastewater by means of response surface methodology

This work discusses the decolorization and degradation of textile azo dye solutions containing Acid Yellow 36 (AY-36) by the electro-Fenton process (EF) using an undivided electrochemical cell containing a boron doped diamond (BDD) electrode as cathode for H2O2 production. The independent parameters of current density, dye concentration, Fe2 + concentration and electrolysis time in the range of 8–23 mA/cm2, 60–80 mg/L, 0.1–0.3 mM and 10–50 min, respectively, were evaluated. Experimental data were optimized by means of a 24 factorial design and Response Surface Methodology (RSM). These results revealed that the optimal operating conditions to achieve 95.9% efficiency for dye decolorization with complete degradation were current density = 15 mA/cm2, AY-36 concentration = 80 mg/L, Fe2 + content = 0.3 mM and electrolysis time = 50 min. This was confirmed with UV–vis and HPLC assessments during the EF/BDD treatment.

► Hydrogen peroxide was electrogenerated at BDD cathode.
► The dye Acid Yellow 36 was decolorized by electro-Fenton process.
► Decolorization depended on current density, dye and Fe2+ contents and electrolysis time.
► These variable parameters were optimized by response surface methodology.