Bioelectrochemical Dechlorination of 1,2‐DCA with an AQDS‐Functionalized Cathode Serving as Electron Donor

Abstract

In the present study we describe a simple method to immobilize the redox mediator anthraquinone‐2,6‐disulfonate (AQDS) at the surface of graphite electrodes, by means of a commercial anion exchange membrane. Cyclic voltammetry experiments confirmed the efficacy of the immobilization protocol and the long‐term (over 70 days) electrochemical stability of the AQDS‐functionalized electrode. Potentiostatic (–300 mV vs. SHE) batch experiments proved the capability of the electrode in accelerating the bioelectrochemical reductive dechlorination of the groundwater contaminant 1,2‐dichloroethane (1,2‐DCA) to harmless ethene by a mixed microbial culture, by serving as electron donor in the process. Considering the reported broad range of anodic and cathodic reactions catalyzed by AQDS, the herein described functionalized electrode has a remarkable potential for application in the environmental and industrial sector.

Opportunities for groundwater microbial electro‐remediation

“…Through AQDS addition, the 1,2‐DCA dechlorination rate increased from 20 μmol l −1 day −1 in the first work (Leitão et al ., ) to 65 μmol l −1 day −1 in the last one (Leitão et al ., ). AQDS could even be immobilized on the electrode surface for an easier application (Leitão et al ., ).…”

“…The list of chlorinated aliphatic compounds treated in MET can be further extended to the successful treatment of 1,2‐dichloroethane (1,2‐DCA) (Leitão et al ., , , ). Initially, the 1,2‐DCA conversion to ethene was evaluated at different cathode potentials from −300 to −900 mV versus SHE using a Dehalococcoides ‐enriched microbial culture.…”

Progress Towards Bioelectrochemical Remediation of Hexavalent Chromium

“…In environmental remediation, BESs, through biologically-mediated oxidation (at the anode) and reduction (at the cathode), potentially provide a flexible platform for treating many pollutants frequently found at contaminated sites, in co-contamination cases [40,41]. Solid electrodes can serve, in fact, either as an electron sink, for the oxidation of petroleum hydrocarbons [42][43][44] or As(III) [45], or as electron donor, for reduction of chlorinated hydrocarbons [46,47], nitrate [48], or oxidized metals, including Cr(VI) [49].…”