Degradation of diclofenac from aqueous solution by electro-oxidation using different anode materials.

Diclofenac (DCF) is a frequently detected pharmaceutical pollutant in wastewater and poses ecological risks due to its persistence during conventional treatment. This study investigates the electro-oxidation (EO) of DCF using three commercially available anode materials (Ti/IrO2, Pt/Ti, and mixed metal oxide (MMO)) under varying operational conditions to identify an optimal balance between oxidation capacity and energy efficiency. The effects of current density (2-20 mA/cm2), initial pH (3.5-9), and initial DCF concentration (5-40 mg/L) on degradation performance, kinetics, and specific energy consumption (SEC) were evaluated. Among the tested anodes, Pt/Ti showed the highest overall performance, achieving 71.2% DCF removal under the optimum conditions (10 mA/cm2, pH 7, and initial DCF concentration 10 mg/L). Under these conditions, the SEC was calculated as 19.7 kWh/g DCF (140 kWh/m3), indicating an effective balance between degradation efficiency and energy consumption. Kinetic analysis revealed that while increasing current density significantly enhanced degradation rates, it also led to a rise in energy demand. The initial DCF concentration was found to have a relatively minor effect on degradation kinetics. The Pt/Ti anode demonstrated a stable performance across a wide pH range, with neutral pH providing slightly more favorable conditions. The overall results indicate that Pt/Ti anodes can provide stable electrochemical performance with moderate energy consumption and represent a feasible electrode option for DCF removal in EO-based treatment systems.HighlightsComparative evaluation of Pt/Ti, Ti/IrO2, and MMO anodes for DCF degradation.Pt/Ti showed a high DCF removal rate with moderate energy consumption.Higher current density enhanced kinetics; however, it increased energy costs.The Pt/Ti anode demonstrated a stable performance across a wide pH range.Initial DCF concentration showed a relatively minor effect on reaction kinetics.