Electrochemical Advanced Oxidation of Carbamazepine on Boron-Doped Diamond Anodes. Influence of Operating Variables

A wide variety of drugs have been found in wastewater treatment effluents, rivers, and lakes, including analgesics, antibiotics, and antiepileptics. Electrochemical advanced oxidation processes are promising technologies to treat low contents of toxic and biorefractory pollutants in water. Anodic oxidation of carbamazepine, the most frequently detected drug in water bodies, was carried out using boron-doped diamond (BDD) anodes at galvanostatic mode. To optimize the process and study the interaction between the four modified variables (pH, current, concentration of supporting electrolyte Na2SO4, and solution flow rate) a design-of-experiments procedure has been carried out. The influence of these four variables has been evaluated. The influence of current was the greatest in the studied variables, the second one was the salt concentration, and the third one was the flow rate. ANOVA test reported significant for 5 of the 14 involved variables and the response surface methodology technique used to optimize carbamazepine degradation. An optimum carbamazepine degradation of 100% was found at pH 9, flow rate equal to 1.25 cm(3) min(-1), and current density equal to 190 mA cm(-2) using a supporting electrolyte concentration equal to 0.48 mol L-1.