Electrochemical Oxidation of Different Therapeutic Classes of Pharmaceuticals Using Graphite-PVC Composite Electrode

Abstract

This study reports electrochemical treatment of different therapeutic classes of pharmaceuticals (caffeine, prazosin, enalapril, carbamazepine, nifedipine, levonorgestrel, and simvastatin) in a mixture. The electrochemical process was investigated using graphite-PVC anode at different applied voltages (3, 5, and 12 V), initial concentrations of studied pharmaceuticals in aqueous solution (5 and 10 mg/L), and concentrations of sodium chloride (1 and 2 g/L). The % removal of pharmaceuticals increased with the applied voltage, and was found higher than 98% after 50 min of electrolysis at 5 V. Energy consumption ranged between 0.760 and 3.300 Wh/mg using 12 V being the highest value compared to 3 and 5 V. The formation of chlorinated by-products from four selected pharmaceuticals, simvastatin (C₁₁H₁₃Cl₃O₅, and C₁₀H₁₂Cl₄O₃), prazosin (C₁₃H₁₂Cl₃N₅O₃ and C₁₀H₁₁Cl₄N₂O₂), carbamazepine and caffeine (C₁₅H₁₁N₂O₂Cl and C₈H₉N₄O₂Cl) was identified and elucidated using liquid chromatography-time of flight mass spectrometry (LC-TOF/MS).