Reductive Dechlorination

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Woojin Lee - One of the best experts on this subject based on the ideXlab platform.

  • Reductive Dechlorination of carbon tetrachloride by bioreduction of nontronite
    Journal of Hazardous Materials, 2017
    Co-Authors: Sungjun Bae, Ji Bong Joo, Woojin Lee
    Abstract:

    Abstract Reductive Dechlorination of carbon tetrachloride (CT) was investigated during bioreduction of iron-containing clay mineral (i.e., nontronite) by iron-reducing bacteria (Shewanella putrefaciens CN32 (CN32)). In the absence of CT, the production of Fe(II) significantly increased in nontronite suspension with CN32 in 124 d (11.1% of Fe(III) reduction), resulting in formation of new secondary Fe(II) mineral phase (i.e., vivianite (FeII3(PO4)2·8H2O)). In the presence of CT, an acceleration of CT Dechlorination was observed after 13 d and it reached almost 68% of removal efficiency at 32 d in nontronite suspension with CN32, which was 1.8 times higher than that by CN32 alone (37%). Significant amounts of formate (30.1%) and CO (2.4%) were measured during the CT Dechlorination in the nontronite suspension with CN32. Results obtained from Fe(II) measurement and X-ray diffraction (XRD) showed the acceleration of Fe(II) production after 13 d and the formation of vivianite in the range of 13–25 d, suggesting that the biogenic vivianite enhanced the CT Dechlorination in this study. Experimental results from batch kinetic tests, Fe(II) measurements, XRD analysis, and by-product study suggested that the formation of vivianite can play a crucial role for the enhanced Reductive Dechlorination of CT in phosphorous enriched subsurface environments with iron-containing clay minerals.

  • synergistic effect of nano sized mackinawite with cyano cobalamin in cement slurries for Reductive Dechlorination of tetrachloroethylene
    Journal of Hazardous Materials, 2016
    Co-Authors: Daeseung Kyung, Sangwoo Kim, Sungjun Bae, Youngho Sihn, M T Amin, A A Alazba, Woojin Lee
    Abstract:

    Experiments were conducted to investigate the Reductive Dechlorination of tetrachloroethylene (PCE) by nano-Mackinawite (nFeS) with cyano-cobalamin (Cbl(III)) in cement slurries. Almost complete degradation of PCE by nFeS-Cbl(III) was observed in cement slurries in 5 h and its degradation kinetics (k(obs-PCE)=0.57 h(-1)) was 6-times faster than that of nFeS-Cbl(III) without the cement slurries. PCE was finally transformed to non-chlorinated organic compounds such as ethylene, acetylene, and C3-C4 hydrocarbons by nFeS-Cbl(III) in cement slurries. X-ray photoelectron spectroscopy and PCE degradation by cement components (SiO2, Al2O3, and CaO) revealed that both the reduced Co species in Cbl(III) and the presence of Ca in cement played an important role for the enhanced Reductive Dechlorination of PCE. The increase in the concentration of Cbl(III) (0.005-0.1 mM), cement ratio (0.05-0.2), and suspension pH (11.5-13.5) accelerated the PCE degradation kinetics by providing more favorable environments for the production of reactive Ca species and reduction of Co species. We also observed that the degradation efficiency of PCE by nFeS-Cbl(III)-cement lasted even at high concentration of PCE. The experimental results obtained from this study could provide fundamental knowledge of redox interactions among nFeS, Cbl(III), and cement, which could significantly enhance Reductive Dechlorination of chlorinated organics in contaminated natural and engineered environments.

  • Enhanced Reductive Dechlorination of tetrachloroethene by nano-sized mackinawite with cyanocobalamin in a highly alkaline condition
    Journal of environmental management, 2015
    Co-Authors: Sangwoo Kim, Taehyung Park, Woojin Lee
    Abstract:

    In this study, we characterize the Reductive Dechlorination of tetrachloroethene (PCE) by nano-sized mackinawite (nFeS) with cobalamin (Cbl(III)) at a high pH and investigate the effects of environmental factors, including the concentrations of the target contaminant, reductant, and catalyst and suspension ions on the Dechlorination kinetics of PCE. Ninety five percent of the PCE was degraded by nFeS with Cbl(III) in 15 h. Cyclic voltammetry conducted with regard to the Reductive Dechlorination showed a higher redox potential of mackinawite under a high-pH condition (−1.01 V), suggesting that the oxidation state of the central cobalt ion in the cobalamin could be reduced to Cbl(I). The change of cobalamin species on the nFeS surface was verified under different pH conditions by UV–vis spectroscopy. The rate constant of PCE Dechlorination increased from 0.1582 to 0.4284 h−1 due to the increase in the nFeS content (2.085–20.85 g/L). As the concentration of Cbl(III) increased from 0 to 0.5 mM, the Dechlorination kinetics of PCE was accelerated (0–1.4091 h−1) but reached a state of equilibrium from 0.5 to 1 mM. The increase in the initial PCE concentration (0.035–1.0 mM) slowed down the Dechlorination kinetics (0.2036–0.0962 h−1). The Dechlorination kinetics was enhanced by 1.5–11 times when 10 mM of ions (Na+, K+, Mg2+, Ca2+, CO32−, SO42−, and NO3−) were added, while an addition of HCO3 decelerated it by 10 times. This study can provide background knowledge pertaining to the PCE Dechlorination by a natural reductant under a high-pH condition and the effect of environmental factors on the Dechlorination kinetics for the development of novel remediation technologies.

  • enhanced Reductive Dechlorination of tetrachloroethene during reduction of cobalamin iii by nano mackinawite
    Journal of Hazardous Materials, 2012
    Co-Authors: Amnorzahira Amir, Woojin Lee
    Abstract:

    Abstract We demonstrated adsorption and reduction of cobalamin(III) (Co(III)) on nano-mackinawite (nFeS) surface and their impact on Reductive Dechlorination of tetrachloroethene (PCE). The adsorption of Co(III) on the nFeS surface followed Langmuir isotherm and the reduction of Co(III) provided different reactive surface chemical species on nFeS surface. Content of Fe2+ S on nFeS surface decreased (45.9–14.5%) as Fe2+ S was oxidized to Fe3+ S and Fe3+ O coupled with the surface reduction of Co(III) to cobalamin(II) (Co(II)). S2− and Sn2− contents on the nFeS surface also decreased by 48.5% and 82.3%, respectively during the formation of sulfidecobalamin(II) ( S2− Co(II)) by the reactive surface sulfur. PCE was fully degraded in nFeS Co(III) suspension at pH 8.3 in 120 h. The Dechlorination kinetic rate constant of PCE in the nFeS Co(III) suspension (kFeS Co(III) = 0.188 ± 0.003 h−1) was 145 times greater than that in nFeS suspension, showing a potential role of S2− Co(II) as an electron transfer mediator to shuttle electrons for the enhanced Reductive Dechlorination. PCE was transformed to acetylene and 1,3-butadiene as major products via Reductive β-elimination and isomerization reactions, respectively. The experimental findings can provide basic knowledge to identify a reaction mechanism for the enhanced Reductive Dechlorination of chlorinated organic by biogeochemical reactions possibly observed in natural reducing environments.

  • enhanced Reductive Dechlorination of tetrachloroethene by nano sized zero valent iron with vitamin b12
    Chemical Engineering Journal, 2011
    Co-Authors: Amnorzahira Amir, Woojin Lee
    Abstract:

    Abstract We demonstrated that the addition of vitamin B 12 can significantly enhance the Reductive Dechlorination of tetrachloroethene (PCE) by nano-sized zero valent iron (nZVI). A remarkable Reductive Dechlorination of PCE (0.25 ± 0.01 h −1 ) was observed in nZVI suspension (0.05 g/24 mL) with 0.5 mM vitamin B 12 in 6 h, while no significant Reductive Dechlorination of PCE was observed in the nZVI suspension without vitamin B 12 . Vitamin B 12r of which central metal is Co 2+ was identified as predominant specie during the Dechlorination of PCE. The Dechlorination kinetic rate constant of PCE in nZVI/vitamin B 12 system was significantly dependent on the suspension pH and concentrations of vitamin B 12 , nZVI, and PCE. An enhancement in PCE Dechlorination kinetic (0.180 ± 0.006–0.709 ± 0.004 h −1 ) due to the formation of hydroxovitamin B 12r was observed by increasing the suspension pH (5–9). The Dechlorination kinetic rate constant of PCE increased proportionally (0.0010 ± 0.0009–1.3660 ± 0.2940 h −1 ) as the concentration of vitamin B 12 increased (5 nM to 5 mM). As the concentration of nZVI increased by 50 times (0.01–0.50 g), the Dechlorination kinetic increased approximately 137 times (0.007 ± 0.001–0.961 ± 0.182 h −1 ). However, the Dechlorination kinetic decelerated (0.184 ± 0.010–0.039 ± 0.006 h −1 ) as PCE concentration increased (0.005–1.0 mM). This study provides basic understanding on the role of vitamin B 12 /vitamin B 12r as an electron mediator in the enhanced Reductive Dechlorination of PCE by nZVI occasionally observed in remediation sites.

Frank E Loffler - One of the best experts on this subject based on the ideXlab platform.

  • impact of fixed nitrogen availability on dehalococcoides mccartyi Reductive Dechlorination activity
    Environmental Science & Technology, 2019
    Co-Authors: Devrim Kaya, Birthe V Kjellerup, Karuna Chourey, Robert L Hettich, Dora M Taggart, Frank E Loffler
    Abstract:

    Biostimulation to promote Reductive Dechlorination is widely practiced, but the value of adding an exogenous nitrogen (N) source (e.g., NH4+) during treatment is unclear. This study investigates th...

  • Nitrous Oxide Is a Potent Inhibitor of Bacterial Reductive Dechlorination.
    Environmental Science & Technology, 2019
    Co-Authors: Yongchao Yin, Jun Yan, Gao Chen, Fadime Kara Murdoch, Nina Pfisterer, Frank E Loffler
    Abstract:

    Organohalide-respiring bacteria are key players for the turnover of organohalogens. At sites impacted with chlorinated ethenes, bioremediation promotes Reductive Dechlorination; however, stoichiometric conversion to environmentally benign ethene is not always achieved. We demonstrate that nitrous oxide (N2O), a compound commonly present in groundwater, inhibits organohalide respiration. N2O concentrations in the low micromolar range decreased Dechlorination rates and resulted in incomplete Dechlorination of tetrachloroethene (PCE) in Geobacter lovleyi strain SZ and of cis-1,2-dichloroethene ( cDCE) and vinyl chloride (VC) in Dehalococcoides mccartyi strain BAV1 axenic cultures. Presumably, N2O interferes with Reductive Dechlorination by reacting with super-reduced Co(I)-corrinoids of Reductive dehalogenases, which is supported by the finding that N2O did not inhibit corrinoid-independent fumarate-to-succinate reduction in strain SZ. Kinetic analyses revealed a best fit to the noncompetitive Michaelis-Menten inhibition model and determined N2O inhibitory constants, KI, for PCE and cDCE Dechlorination of 40.8 ± 3.8 and 21.2 ± 3.5 μM in strain SZ and strain BAV1, respectively. The lowest KI value of 9.6 ± 0.4 μM was determined for VC to ethene Reductive Dechlorination in strain BAV1, suggesting that this crucial Dechlorination step for achieving detoxification is most susceptible to N2O inhibition. Groundwater N2O concentrations exceeding 100 μM are not uncommon, especially in watersheds impacted by nitrate runoff from agricultural sources. Thus, dissolved N2O measurements can inform about cDCE and VC stalls at sites impacted with chlorinated ethenes.

  • guided cobalamin biosynthesis supports dehalococcoides mccartyi Reductive Dechlorination activity
    Philosophical Transactions of the Royal Society B, 2013
    Co-Authors: Jun Yan, Frank E Loffler, Yi Yang
    Abstract:

    Dehalococcoides mccartyi strains are corrinoid-auxotrophic Bacteria and axenic cultures that require vitamin B12 (CN-Cbl) to conserve energy via organohalide respiration. Cultures of D. mccartyi strains BAV1, GT and FL2 grown with limiting amounts of 1 µg l−1 CN-Cbl quickly depleted CN-Cbl, and Reductive Dechlorination of polychlorinated ethenes was incomplete leading to vinyl chloride (VC) accumulation. In contrast, the same cultures amended with 25 µg l−1 CN-Cbl exhibited up to 2.3-fold higher Dechlorination rates, 2.8–9.1-fold increased growth yields, and completely consumed growth-supporting chlorinated ethenes. To explore whether known cobamide-producing microbes supply Dehalococcoides with the required corrinoid cofactor, co-culture experiments were performed with the methanogen Methanosarcina barkeri strain Fusaro and two acetogens, Sporomusa ovata and Sporomusa sp. strain KB-1, as Dehalococcoides partner populations. During growth with H2/CO2, M. barkeri axenic cultures produced 4.2 ± 0.1 µg l−1 extracellular cobamide (factor III), whereas the Sporomusa cultures produced phenolyl- and p -cresolyl-cobamides. Neither factor III nor the phenolic cobamides supported Dehalococcoides Reductive Dechlorination activity suggesting that M. barkeri and the Sporomusa sp. cannot fulfil Dehalococcoides ' nutritional requirements. Dehalococcoides Dechlorination activity and growth occurred in M. barkeri and Sporomusa sp. co-cultures amended with 10 µM 5′,6′-dimethylbenzimidazole (DMB), indicating that a cobalamin is a preferred corrinoid cofactor of strains BAV1, GT and FL2 when grown with chlorinated ethenes as electron acceptors. Even though the methanogen and acetogen populations tested did not produce cobalamin, the addition of DMB enabled guided biosynthesis and generated a cobalamin that supported Dehalococcoides ' activity and growth. Guided cobalamin biosynthesis may offer opportunities to sustain and enhance Dehalococcoides activity in contaminated subsurface environments.

  • dehalococcoides and Reductive Dechlorination of chlorinated solvents
    2013
    Co-Authors: Kirsti M Ritalahti, Frank E Loffler, Stephen H. Zinder
    Abstract:

    Since the beginning of the twentieth century, short-chain C1 to C3 chlorinated aliphatic hydrocarbons (CAHs) have been manufactured in large amounts and extensively used in industrial, military, agricultural and household applications. The widespread use of CAHs is based on their desirable properties including low cost, easy availability, excellence as solvents, chemical stability, and fire safety (i.e., most chlorinated solvents are nonflammable and do not form explosive mixtures with air). The widespread use, careless handling and storage, ignorance of health effects and environmental dangers, and the lack of regulations over decades of extensive use has resulted in wide-ranging groundwater contamination. A major strategy for the bioremediation of these solvents is Reductive Dechlorination by microorganisms, most predominantly members of the Dehalococcoides group, the only microbes known to detoxify chlorinated ethenes to ethene. Members of this group have streamlined genomes highly adapted to using chlorinated hydrocarbons as electron acceptors, and are likely to play important roles in Reductive dehalogenation of diverse organohalides in the environment.

  • graphite electrode as a sole electron donor for Reductive Dechlorination of tetrachlorethene by geobacter lovleyi
    Applied and Environmental Microbiology, 2008
    Co-Authors: Sarah Strycharz, Trevor L Woodard, Jessica P Johnson, Kelly P Nevin, Robert A Sanford, Frank E Loffler
    Abstract:

    The possibility that graphite electrodes can serve as the direct electron donor for microbially catalyzed Reductive Dechlorination was investigated with Geobacter lovleyi. In an initial evaluation of whether G. lovleyi could interact electronically with graphite electrodes, cells were provided with acetate as the electron donor and an electrode as the sole electron acceptor. Current was produced at levels that were ca. 10-fold lower than those previously reported for Geobacter sulfurreducens under similar conditions, and G. lovleyi anode biofilms were correspondingly thinner. When an electrode poised at −300 mV (versus a standard hydrogen electrode) was provided as the electron donor, G. lovleyi effectively reduced fumarate to succinate. The stoichiometry of electrons consumed to succinate produced was 2:1, the ratio expected if the electrode served as the sole electron donor for fumarate reduction. G. lovleyi effectively reduced tetrachloroethene (PCE) to cis-dichloroethene with a poised electrode as the sole electron donor at rates comparable to those obtained when acetate serves as the electron donor. Cells were less abundant on the electrodes when the electrodes served as an electron donor than when they served as an electron acceptor. PCE was not reduced in controls without cells or when the current supply to cells was interrupted. These results demonstrate that G. lovleyi can use a poised electrode as a direct electron donor for Reductive Dechlorination of PCE. The ability to colocalize dechlorinating microorganisms with electrodes has several potential advantages for bioremediation of subsurface chlorinated contaminants, especially in source zones where electron donor delivery is challenging and often limits Dechlorination.

Lisa Alvarezcohen - One of the best experts on this subject based on the ideXlab platform.

  • acetylene fueled trichloroethene Reductive Dechlorination in a groundwater enrichment culture
    Mbio, 2021
    Co-Authors: Sara Gushgaridoyle, Shaun M. Baesman, Ronald S. Oremland, Ray Keren, Denise M Akob, Jillian F Banfield, Lisa Alvarezcohen
    Abstract:

    ABSTRACT In aquifers, acetylene (C2H2) is a product of abiotic degradation of trichloroethene (TCE) catalyzed by in situ minerals. C2H2 can, in turn, inhibit multiple microbial processes including TCE Dechlorination and metabolisms that commonly support Dechlorination, in addition to supporting the growth of acetylenotrophic microorganisms. Previously, C2H2 was shown to support TCE Reductive Dechlorination in synthetic, laboratory-constructed cocultures containing the acetylenotroph Pelobacter sp. strain SFB93 and Dehalococcoides mccartyi strain 195 or strain BAV1. In this study, we demonstrate TCE and perchloroethene (PCE) Reductive Dechlorination by a microbial community enriched from contaminated groundwater and amended with C2H2 as the sole electron donor and organic carbon source. The metagenome of the stable, enriched community was analyzed to elucidate putative community functions. A novel anaerobic acetylenotroph in the phylum Actinobacteria was identified using metagenomic analysis. These results demonstrate that the coupling of acetylenotrophy and Reductive Dechlorination can occur in the environment with native bacteria and broaden our understanding of biotransformation at contaminated sites containing both TCE and C2H2. IMPORTANCE Understanding the complex metabolisms of microbial communities in contaminated groundwaters is a challenge. PCE and TCE are among the most common groundwater contaminants in the United States that, when exposed to certain minerals, exhibit a unique abiotic degradation pathway in which C2H2 is a product. C2H2 can act as both an inhibitor of TCE Dechlorination and of supporting metabolisms and an energy source for acetylenotrophic bacteria. Here, we combine laboratory microcosm studies with computational approaches to enrich and characterize an environmental microbial community that couples two uncommon metabolisms, demonstrating unique metabolic interactions only yet reported in synthetic, laboratory-constructed settings. Using this comprehensive approach, we have identified the first reported anaerobic acetylenotroph in the phylum Actinobacteria, demonstrating the yet-undescribed diversity of this metabolism that is widely considered to be uncommon.

  • acetylene fuels tce Reductive Dechlorination by defined dehalococcoides pelobacter consortia
    Environmental Science & Technology, 2017
    Co-Authors: Xinwei Mao, Shaun M. Baesman, Ronald S. Oremland, Tong Liu, Sara Gushgari, Abigail Landers, Lisa Alvarezcohen
    Abstract:

    Acetylene (C2H2) can be generated in contaminated groundwater sites as a consequence of chemical degradation of trichloroethene (TCE) by in situ minerals, and C2H2 is known to inhibit bacterial Dechlorination. In this study, we show that while high C2H2 (1.3 mM) concentrations reversibly inhibit Reductive Dechlorination of TCE by Dehalococcoides mccartyi isolates as well as enrichment cultures containing D. mccartyi sp., low C2H2 (0.4 mM) concentrations do not inhibit growth or metabolism of D. mccartyi. Cocultures of Pelobacter SFB93, a C2H2-fermenting bacterium, with D. mccartyi strain 195 or with D. mccartyi strain BAV1 were actively sustained by providing acetylene as the electron donor and carbon source while TCE or cis-DCE served as the electron acceptor. Inhibition by acetylene of Reductive Dechlorination and methanogenesis in the enrichment culture ANAS was observed, and the inhibition was removed by adding Pelobacter SFB93 into the consortium. Transcriptomic analysis of D. mccartyi strain 195 sho...

  • perfluoroalkyl acids inhibit Reductive Dechlorination of trichloroethene by repressing dehalococcoides
    Environmental Science & Technology, 2016
    Co-Authors: T S Weathers, Lisa Alvarezcohen, Katie C Hardingmarjanovic, Christopher P Higgins, Jonathan O Sharp
    Abstract:

    The subsurface recalcitrance of perfluoroalkyl acids (PFAAs) derived from aqueous film-forming foams could have adverse impacts on the microbiological processes used for the bioremediation of co-mingled chlorinated solvents such as trichloroethene (TCE). Here, we show that Reductive Dechlorination by a methanogenic, mixed culture was significantly inhibited when exposed to concentrations representative of PFAA source zones (>66 mg/L total of 11 PFAA analytes, 6 mg/L each). TCE Dechlorination, cis-dichloroethene and vinyl chloride production and Dechlorination, and ethene generation were all inhibited at these PFAA concentrations. Phylogenetic analysis revealed that the abundances of 65% of the operational taxonomic units (OTUs) changed significantly when grown in the presence of PFAAs, although repression or enhancement resulting from PFAA exposure did not correlate with putative function or phylogeny. Notably, there was significant repression of Dehalococcoides (8-fold decrease in abundance) coupled with a corresponding enhancement of methane-generating Archaea (a 9-fold increase). Growth and Dechlorination by axenic cultures of Dehalococcoides mccartyi strain 195 were similarly repressed under these conditions, confirming an inhibitory response of this pivotal genus to PFAA presence. These results suggest that chlorinated solvent bioattenuation rates could be impeded in subsurface environments near PFAA source zones.

Bruce E Rittmann - One of the best experts on this subject based on the ideXlab platform.

  • managing methanogens and homoacetogens to promote Reductive Dechlorination of trichloroethene with direct delivery of h2 in a membrane biofilm reactor
    Biotechnology and Bioengineering, 2012
    Co-Authors: Michal C Zivel, Rolf U Halden, Sudeep C Popat, Katherine Cai, Rosa Krajmalnikbrown, Bruce E Rittmann
    Abstract:

    A study with H(2)-based membrane biofilm reactors (MBfRs) was undertaken to examine the effectiveness of direct H(2) delivery in ex-situ Reductive Dechlorination of chlorinated ethenes. Trichloroethene (TCE) could be Reductively dechlorinated to ethene with up to 95% efficiency as long as the pH-increase effects of methanogens and homoacetogens were managed and dechlorinators were selected for during start-up by creating H(2) limitation. Based on quantitative PCR, the dominant bacterial groups in the biofilm at the end of reactor operation were Dehalococcoides, Geobacter, and homoacetogens. Pyrosequencing confirmed the dominance of the dechlorinators and identified Acetobacterium as the key homoacetogen. Homoacetogens outcompeted methanogens for bicarbonate, based on the effluent concentration of acetate, by suppressing methanogens during batch start-up. This was corroborated by the methanogenesis functional gene mcrA, which was 1-2 orders of magnitude lower than the FTHFS functional gene for homoacetogens. Imaging of the MBfR fibers using scanning electron microscopy showed a distinct Dehalococcoides-like morphology in the fiber biofilm. These results support that direct addition of H(2) can allow for efficient and complete Reductive Dechlorination, and they shed light into how H(2)-fed biofilms, when operated to manage methanogenic and homoacetogenic activity, can be used for ex-situ bioremediation of chlorinated ethenes.

  • bio Reductive Dechlorination of 1 1 1 trichloroethane and chloroform using a hydrogen based membrane biofilm reactor
    Biotechnology and Bioengineering, 2007
    Co-Authors: Jin Wook Chung, Bruce E Rittmann
    Abstract:

    A H2-based, denitrifying and sulfate-reducing membrane biofilm reactor (MBfR) was effective for removing 1,1,1-trichloroethane (TCA) and chloroform (CF) by Reductive Dechlorination. When either TCA or CF was first added to the MBfR, Reductive Dechlorination took place immediately and then increased over 3 weeks, suggesting enrichment for TCA- or CF-dechlorinating bacteria. Increasing the H2 pressure increased the Dechlorination rates of TCA or CF, and it also increased the rate of sulfate reduction. Increased sulfate loading allowed more sulfate reduction, and this competed with Reductive Dechlorination, particularly the second steps. The acceptor flux normalized by effluent concentration can be an efficient indicator to gauge the intrinsic kinetics of the MBfR biofilms for the different reduction reactions. The analysis of normalized rates showed that the kinetics for Reductive-Dechlorination reactions were slowed by reduced H2 bio-availability caused by a low H2 pressure or competition from sulfate reduction. Biotechnol. Bioeng. 2007;97:52–60. © 2006 Wiley Periodicals, Inc.

Patricia Leitao - One of the best experts on this subject based on the ideXlab platform.

  • bioelectrochemically assisted Reductive Dechlorination of 1 2 dichloroethane by a dehalococcoides enriched microbial culture
    Bioresource Technology, 2015
    Co-Authors: Mauro Majone, Simona Rossetti, Patricia Leitao, Henri P A Nouws, Anthony S Danko, Federico Aulenta
    Abstract:

    Abstract The aim of this study was to verify the possibility to use a polarized graphite electrode as an electron donor for the Reductive Dechlorination of 1,2-dichloroethane, an ubiquitous groundwater contaminant. The rate of 1,2-DCA Dechlorination almost linearly increased by decreasing the set cathode potential over a broad range of set cathode potentials (i.e., from −300 mV to −900 mV vs. the standard hydrogen electrode). This process was primarily dependent on electrolytic H2 generation. On the other hand, Reductive Dechlorination proceeded (although quite slowly) with a very high Coulombic efficiency (near 70%) at a set cathode potential of −300 mV, where no H2 production occurred. Under this condition, Reductive Dechlorination was likely driven by direct electron uptake from the surface of the polarized electrode. Taken as a whole, this study further extends the range of chlorinated contaminants which can be treated with bioelectrochemical systems.