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

• Published in: Environmental monitoring and assessment Vol. 195; no. 4; p. 461
• Main Authors: Mussa, Zainab Haider, Al-Qaim, Fouad Fadhil
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.04.2023; Springer Nature B.V
• Subjects: Anodes; Atmospheric Protection/Air Quality Control/Air Pollution; By products; Byproducts; Chemical oxygen demand; Chlorides; Chlorine compounds; Constants; Degradation; Diclofenac; Earth and Environmental Science; Ecology; Ecotoxicology; Electric potential; Electrochemical oxidation; Electrochemistry; Electrodes; Electrolysis; Electrolytes; Electrolytes - chemistry; Energy consumption; Environment; Environmental Management; Environmental Monitoring; Environmental science; Graphite; Graphite - chemistry; HPLC; Liquid chromatography; Monitoring/Environmental Analysis; Nonsteroidal anti-inflammatory drugs; Organic compounds; Oxidation; Oxidation process; Oxidation-Reduction; Oxygen; Oxygen requirement; Rate constants; Removal; Sodium; Sodium channels (voltage-gated); Sodium Chloride; Substrates; Voltage; Water Pollutants, Chemical - chemistry; Remediation; Chlorinated by-products; Electrochemical process; HPLC; Graphite; Diclofenac
• ISSN: 0167-6369; 1573-2959
• DOI: 10.1007/s10661-023-11085-0

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: 0.5 g NaCl, 5 V, and 80 min of electrolysis, while the removal% of chemical oxygen demand (COD) was 88% under the same conditions, but 360 min 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 0.054 min −1 , between 0.0024 and 0.0326 min −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 0.1 g NaCl and 7 V, respectively. Some chlorinated by-products, C 13 H 18 Cl 2 NO 5 , C 11 H 10 Cl 3 NO 4 , and C 13 H 13 Cl 5 NO 5 , were selected and elucidated using LC-TOF/MS.