Oil removal from an oil-in-water emulsion by electrochemical process using Taguchi method

Abstract

In this study an electrochemical treatment process of an oil-in-water emulsion was investigated using an anode composed of carbon-polytetrafluoroethylene and manganese oxide as an electrocatalyst. The effects of operating parameters including initial chemical oxygen demand (COD), NaCl concentration, pH, voltage and time on decreasing COD of the emulsion were studied. The Taguchi method was used in the design of experiments, and to analyze data. L₁₆(4⁵) orthogonal array was selected for experimental designing. Analysis of variance was applied to determine optimum conditions and the most significant parameters affecting the response of the process. According to the results of analysis, time is the most effective parameter, with percentage contribution of 65.6% followed by NaCl concentration of 17.49%, voltage of 7.29%, and initial COD concentration of 7.09%. Also it was found that pH has an insignificant effect on COD removal percentage. The optimum conditions were found as follows: the fourth level of initial COD (1,200 mg/L) and NaCl concentration (1,500 mg/L), third level of voltage (5 V) and fourth level of time (180 min). Finally the confirmation test was performed under optimum conditions. Observed value of this experiment (70.11%) was within the range of confidence limit of predicted performance (73.19 ± 5%).

Keywords:

• Oil-in-water emulsion
• Electrocatalyst
• Electrochemical treatment
• Taguchi method