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Dechlorination of trichloroethene in a continuous-flow bioelectrochemical reactor: Effect of cathode potential on rate, selectivity, and electron transfer mechanisms

TitoloDechlorination of trichloroethene in a continuous-flow bioelectrochemical reactor: Effect of cathode potential on rate, selectivity, and electron transfer mechanisms
Tipo di pubblicazioneArticolo su Rivista peer-reviewed
Anno di Pubblicazione2011
AutoriAulenta, F., Tocca L., Verdini R., Reale P., and Majone M.
RivistaEnvironmental Science and Technology
Volume45
Paginazione8444-8451
ISSN0013936X
Parole chiavearticle, Average rate, bacterium, Biodegradation, Bioelectrochemical reactors, Bioreactor, Bioreactors, Bioremediation, carbon, carbon source, Cathode potential, Cathodes, continuous flow bioelectrochemical reactor, continuous flow reactor, Continuous-flow, dechlorination, Effect of cathode, electric current, Electric current measurement, Electricity, electrochemical analysis, electrochemical method, Electrochemical Techniques, Electrochemistry, electrode, Electrodes, electron, Electron donors, Electron transfer mechanisms, Electron transitions, electron transport, Electrons, Environmental, Extracellular electron transfer, Fluid, Graphite, Graphite cathodes, ground water, groundwater, halogenation, Hydrogen, Hydrogen production, Indoles, Long-term viability, methanogenesis, Organic carbon, Oxidation-Reduction, performance assessment, reaction rate, Reductive dechlorination, remediation, Standard hydrogen electrodes, Time Factors, Trichloroethenes, Trichloroethylene, Waste disposal
Abstract

The exciting discovery that dechlorinating bacteria can use polarized graphite cathodes as direct electron donors in the reductive dechlorination has prompted investigations on the development of novel bioelectrochemical remediation approaches. In this work, we investigated the performance of a bioelectrochemical reactor for the treatment of trichloroethene (TCE). The reactor was continuously operated for about 570 days, at different potentiostatically controlled cathode potentials, ranging from -250 mV to -750 mV vs standard hydrogen electrode. The rate and extent of TCE dechlorination, as well as the competition for the available electrons, were highly dependent on the set cathode potential. When the cathode was controlled at -250 mV, no abiotic hydrogen production occurred and TCE dechlorination (predominantly to cis-DCE and VC), most probably sustained via direct extracellular electron transfer, proceeded at an average rate of 15.5 ± 1.2 μmol e -/L d. At this cathode, potential methanogenesis was almost completely suppressed and dechlorination accounted for 94.7 ± 0.1% of the electric current (15.0 ± 0.8 μA) flowing in the system. A higher rate of TCE dechlorination (up to 64 ± 2 μmol e -/L d) was achieved at cathode potentials lower than -450 mV, though in the presence of a very active methanogenesis which accounted for over 60% of the electric current. Remarkably, the bioelectrochemical reactor displayed a stable and reproducible performance even without the supply of organic carbon sources with the feed, confirming long-term viability. © 2011 American Chemical Society.

Note

cited By 35

URLhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-80053409340&doi=10.1021%2fes202262y&partnerID=40&md5=fbfc7d00e161eddb434e1067b95a61a9
DOI10.1021/es202262y
Citation KeyAulenta20118444