Applied Chemical Engineering

Sequential combination of electrocoagulation and Electro-fenton for COD removal of real petroleum refinery wastewater

Murtada S. Khalaf

Chemical Engineering Department, College of Engineering, University of Babylon, Babil, 51002, Iraq

Alaa N. Ghanim

Chemical Engineering Department, College of Engineering, University of Babylon, Babil, 51002, Iraq

DOI: https://doi.org/10.59429/ace.v8i4.5818

Keywords: Electrocoagulation; Electro-Fenton ; COD ; Kinetics ; hydrogen peroxide

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Abstract

Electrocoagulation (EC) and electro-Fenton (EF) are effective electrochemical methods utilized for the removal of organic pollutants from wastewater. Electrochemical techniques facilitate the removal of contaminants by metal dissolution., EF creates hydroxyl radicals (•OH) by reacting H₂O₂ with Fe²⁺, facilitating advanced oxidation. This study treated the Najaf refinery, Iraq wastewater with a combination EC/EF procedure. The raw wastewater had an initial chemical oxygen demand (COD) of 700 mg/L. EC was conducted for 60 minutes at pH = 7 and room temperature using four iron electrodes (total active area: 100 cm²). The EF process was carried out for 120 minutes at a pH of 3 utilizing two porous graphite electrodes with an area of 60 cm² each. The experiments included variations in the current density (20–50 mA/cm²), hydrogen peroxide H₂O₂ concentration addition (0.5–2.0 g/L), and pH values. The combined system attained a maximum COD removal efficiency of 99.42% at 40 mA/cm² and 0.5 g/L H₂O₂ , validating the significant potential of this approach for industrial wastewater treatment.

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