Electrochemical degradation of trichloroethylene in aqueous solution by bipolar graphite electrodes

Abstract

In this study, we tested the use of the bipolar electrodes to enhance electrochemical degradation of trichloroethylene (TCE) in an undivided, flow-through electrochemical reactor. The bipolar electrode forms when an electrically conductive material polarizes between feeder electrodes that are connected to a direct current source and, therefore, creates an additional anode/cathode pair in the system. We hypothesize that bipolar electrodes will generate additional oxidation/reduction zones to enhance TCE degradation. The graphite cathode followed by graphite anode sequence were operated without a bipolar electrode as well as with one and two bipolar graphite electrodes. The system without bipolar electrodes degraded 29% of TCE while the system with one and two bipolar electrodes degraded 38% and 66% of TCE, respectively. It was found that the removal mechanism for TCE in bipolar mode includes hydrodechlorination at the feeder cathode, and oxidation through reaction with peroxide. The results show that the bipolar electrodes presence enhance TCE removal efficiency and rate and imply that they can be used to improve electrochemical treatment of contaminated groundwater.

Electrochemical Advanced Oxidation Processes (EAOP) to degrade per- and polyfluoroalkyl substances (PFASs)

“…The configuration might also behave as a flow-through cell (cylinder or porous panels) (d, e) to increase the transportation efficiency [33,36]. In Figure 3(d, e), in order to enhance the degradation efficiency, the space between the anode and cathode can be filled with nanomaterials (such as functionalised activated carbon) or an additional electrode couple [34,51]. …”

“…As a compulsory component of an electrochemical cell, the cathode reaction should be designed to maximise its benefit towards the degradation process. The emission of hydrogen on the cathode surface, as well as the production of H 2 O 2 [41], the reduction of metal ions (such as from Fe 3+ to Fe 2+ ) and the dechlorination and debromination of organohalogens should also be noticed [51,55,70,71].…”

“…Further research is thus highly desirable. For example, a similar approach has been described using a bipolar electrode to enhance EAOP's performance [51].…”

Transient reactive transport model for physico-chemical transformation by electrochemical reactive barriers

“…Electrochemical processes were initially investigated for oxidation of phenolic compounds in industrial wastewater [9–11]. The method was expanded for removal of various organic and inorganic contaminants for in situ groundwater remediation [2,4,5,12,13]. Research was focused on the influence of the electrode material, electrolyte composition, current density, and pH monitoring on remediation efficiency.…”

Electrochemical dechlorination of trichloroethylene in the presence of natural organic matter, metal ions and nitrates in a simulated karst media

“…Electrochemical methods are of interest for treating such contaminants in groundwater because of the capability to adjust redox conditions to changes in the influent composition and flow rate [2–4]. Electrochemical processes are effective for removal of chlorinated solvents such as trichloroethylene (TCE), regulated metals, and nitrates [5] via electrochemically induced oxidation or reduction mechanisms [6–10]. Indirect electrochemical reduction of TCE via hydrochlorination involves the reaction of chlorinated compounds with atomic hydrogen produced at the cathode due to water electrolysis [11].…”