A non-steroidal drug "diclofenac" is a substrate for electrochemical degradation process using graphite anode.

Abstract

In the electrochemical degradation process, the elimination of organic pollutants could be enhanced using supporting electrolyte and applied voltage. After degradation of the target organic compound, some by-products are formed. Chlorinated by-products are the main products formed in the presence of sodium chloride. In the present study, an electrochemical oxidation process has been applied to diclofenac (DCF) using graphite as an anode and sodium chloride (NaCl) as a supporting electrolyte. Monitoring the removal of the by-products and elucidating them were provided using HPLC and LC-TOF/MS, respectively. A high removal% of 94% DCF was observed under the conditions: 0.5g NaCl, 5V, and 80min of electrolysis, while the removal% of chemical oxygen demand (COD) was 88% under the same conditions, but 360min of electrolysis was required. The pseudo-first-order rate constant values were quite varied based on the selected experimental conditions; the rate constants were between 0.0062 and 0.054min-1, between 0.0024 and 0.0326min-1 under the influence of applied voltage and sodium chloride, respectively. The maximum values of energy consumption were 0.93 and 0.55 Wh/mg using 0.1g NaCl and 7V, respectively. Some chlorinated by-products, C13H18Cl2NO5, C11H10Cl3NO4, and C13H13Cl5NO5, were selected and elucidated using LC-TOF/MS.