Degradation by PULSE Corona Discharges: STUDY ON the POSSIBLE Chemical Degradation Pathway for Diclofenac

DEGRADATION BY PULSE CORONA DISCHARGES: STUDY ON THE POSSIBLE CHEMICAL DEGRADATION PATHWAY FOR DICLOFENAC

Torres-Godoy, C., Tennessee Technological University

Dr. Callender, A., Tennessee Technological University

Dr Arce, P, E., Tennessee Technological University

Dr George, D., Tennessee Technological University

The removal of hazardous organic pollutants, such as, polychlorinated biphenyls (PCB’s), polycyclic aromatic hydrocarbons (benzopyrene, dibenzo anthracene), pesticides (DDT, lindane), pharmaceutical products (Diclofenac, Ibuprofen, Carbamazepine) from waste water is a growing issue in environmental science and technology. Innovative methods for water remediation have been examined for removing contaminants from waste sites.

Pulsed corona discharge (PCD) is a non-thermal plasma technology characterized by low gas temperatures and high electron temperatures. This technology has the potential of effective water decontamination and the capability of efficient removal or degradation of organic contaminants. Two key aspects (chemical and physical) exist during a pulsed corona discharge process, and are thought to occur simultaneously in synergism for direct or indirect degradation of organic compounds. The chemical aspect of the process, which is the main focus of this research, mainly involves the formation of various active radicals, such as, ^.OH. ^.H, ^.O, ^.O₂ and ^.HO₂ and active molecules, such as, H₂O₂ and O₃ and their chemical reactions and pathways. All these active species and reactions involve a high oxidation potential to break the molecular bonds of organic contaminants; and, therefore, to lead to effective decontamination of water fluent.

Using the fundamentals of organic chemistry with pulsed corona discharge principles, this research explores the degradation pathway of diclofenac in PCD using LC-MS to identify the intermediate degradation products.  The rate of diclofenac degradation is confirmed through the use of ion-exchange chromatography to determine the amount of chloride released.  The role of parameters such as electrode distance (gap) and solution conductivity are also assessed.