Electrochemical degradation of acid orange II dye using mixed metal oxide anode: Role of supporting electrolytes

• Factorial design was applied to the optimization of MMO anodic oxidations.
• The oxidation of AO II was strongly favored by the presence of chlorides.
• A sudden rise in the significance of variables was observed for chloride media.
• Evidences from electrochemical measurements were presented.

Here, the electrochemical degradation of 50 mg/dm3 Acid Orange II dye over mixed metal oxide anode has been conducted in the presence of different supporting electrolytes (sulfate, chloride, and their mixture of different proportion). A factorial design methodology was adopted to evaluate the statistically important input variables, among treatment time (30–60 min), flow rate (300–600 ml/min), applied current density (2.58–5.16 mA/cm2) and total concentration of supporting electrolytes (1.0–4.0 mM), on degradation performance; the latter was assessed in terms of color removal rate. The results obtained, demonstrated that the electrolytic oxidation was strongly favored by the presence of chlorides. In addition, the information obtained from electrochemical measurements and UV–vis spectra were used to better clarify the different roles of operating parameters recorded.

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