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Wu M, Zhao D, Gu B, Wang Z, Hu J, Yu Z, Yu J. Efficient degradation of aqueous dichloromethane by an enhanced microbial electrolysis cell: Degradation kinetics, microbial community and metabolic mechanisms. J Environ Sci (China) 2024; 139:150-159. [PMID: 38105043 DOI: 10.1016/j.jes.2023.05.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/08/2023] [Accepted: 05/22/2023] [Indexed: 12/19/2023]
Abstract
Dichloromethane (DCM) has been listed as a toxic and harmful water pollutant, and its removal needs attention. Microbial electrolysis cells (MECs) are viewed as a promising alternative for pollutant removal, which can be strengthened from two aspects: microbial inoculation and acclimation. In this study, the MEC for DCM degradation was inoculated with the active sludge enhanced by Methylobacterium rhodesianum H13 (strain H13) and then acclimated in the form of a microbial fuel cell (MFC). Both the introduction of strain H13 and the initiation in MFC form significantly promoted DCM degradation. The degradation kinetics were fitted by the Haldane model, with Vmax, Kh, Ki and vmax values of 103.2 mg/L/hr, 97.8 mg/L, 268.3 mg/L and 44.7 mg/L/hr/cm2, respectively. The cyclic voltammogram implies that DCM redox reactions became easier with the setup of MEC, and the electrochemical impedance spectrogram shows that the acclimated and enriched microbes reduced the charge transfer resistance from the electrode to the electrolyte. In the biofilm, the dominant genera shifted from Geobacter to Hyphomicrobium in acclimation stages. Moreover, Methylobacterium played an increasingly important role. DCM metabolism mainly occurred through the hydrolytic glutathione S-transferase pathway, given that the gene dcmA was identified rather than the dhlA and P450/MO. The exogenous electrons facilitated the reduction of GSSG, directly or indirectly accelerating the GSH-catalyzed dehalogenation. This study provides support for the construction of an efficient and stable MEC for DCM removal in water environment.
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Affiliation(s)
- Meng Wu
- College of Environment, College of Biotechnology and Bioengineering, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou 310014, China
| | - Di Zhao
- Shentuo Environment (Hangzhou) Co. Ltd., Hangzhou 311121, China
| | - Bing Gu
- Zhejiang Tianyi Environmental Co. Ltd., Hangzhou 310000, China
| | - Ziru Wang
- College of Environment, College of Biotechnology and Bioengineering, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou 310014, China
| | - Jun Hu
- College of Environment, College of Biotechnology and Bioengineering, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Zhiliang Yu
- College of Environment, College of Biotechnology and Bioengineering, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou 310014, China
| | - Jianming Yu
- College of Environment, College of Biotechnology and Bioengineering, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou 310014, China.
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Choi C, Wang X, Kwon S, Hart JL, Rooney CL, Harmon NJ, Sam QP, Cha JJ, Goddard WA, Elimelech M, Wang H. Efficient electrocatalytic valorization of chlorinated organic water pollutant to ethylene. NATURE NANOTECHNOLOGY 2023; 18:160-167. [PMID: 36536043 DOI: 10.1038/s41565-022-01277-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 10/17/2022] [Indexed: 06/17/2023]
Abstract
Electrochemistry can provide an efficient and sustainable way to treat environmental waters polluted by chlorinated organic compounds. However, the electrochemical valorization of 1,2-dichloroethane (DCA) is currently challenged by the lack of a catalyst that can selectively convert DCA in aqueous solutions into ethylene. Here we report a catalyst comprising cobalt phthalocyanine molecules assembled on multiwalled carbon nanotubes that can electrochemically decompose aqueous DCA with high current and energy efficiencies. Ethylene is produced at high rates with unprecedented ~100% Faradaic efficiency across wide electrode potential and reactant concentration ranges. Kinetic studies and density functional theory calculations reveal that the rate-determining step is the first C-Cl bond breaking, which does not involve protons-a key mechanistic feature that enables cobalt phthalocyanine/carbon nanotube to efficiently catalyse DCA dechlorination and suppress the hydrogen evolution reaction. The nanotubular structure of the catalyst enables us to shape it into a flow-through electrified membrane, which we have used to demonstrate >95% DCA removal from simulated water samples with environmentally relevant DCA and electrolyte concentrations.
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Affiliation(s)
- Chungseok Choi
- Department of Chemistry, Yale University, New Haven, CT, USA
- Energy Sciences Institute, Yale University, West Haven, CT, USA
| | - Xiaoxiong Wang
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, USA
| | - Soonho Kwon
- Materials and Process Simulation Center (MSC), California Institute of Technology, Pasadena, CA, USA
| | - James L Hart
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, USA
| | - Conor L Rooney
- Department of Chemistry, Yale University, New Haven, CT, USA
- Energy Sciences Institute, Yale University, West Haven, CT, USA
| | - Nia J Harmon
- Department of Chemistry, Yale University, New Haven, CT, USA
- Energy Sciences Institute, Yale University, West Haven, CT, USA
| | - Quynh P Sam
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, USA
| | - Judy J Cha
- Energy Sciences Institute, Yale University, West Haven, CT, USA
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, USA
- Department of Mechanical Engineering and Materials Science, Yale University, West Haven, CT, USA
| | - William A Goddard
- Materials and Process Simulation Center (MSC), California Institute of Technology, Pasadena, CA, USA.
| | - Menachem Elimelech
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, USA.
| | - Hailiang Wang
- Department of Chemistry, Yale University, New Haven, CT, USA.
- Energy Sciences Institute, Yale University, West Haven, CT, USA.
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Williams CK, McCarver GA, Lashgari A, Vogiatzis KD, Jiang JJ. Electrocatalytic Dechlorination of Dichloromethane in Water Using a Heterogenized Molecular Copper Complex. Inorg Chem 2021; 60:4915-4923. [PMID: 33733752 DOI: 10.1021/acs.inorgchem.0c03833] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The remediation of organohalides from water is a challenging process in environment protection and water treatment. Herein, we report a molecular copper(I) complex with two triazole units, CuT2, in a heterogeneous aqueous system that is capable of dechlorinating dichloromethane (CH2Cl2) to afford hydrocarbons (methane, ethane, and ethylene). The catalytic performance is evaluated in water and presented high Faradaic efficiency (average 70% CH4) across a range of potentials (-1.1 to -1.6 V vs Ag/AgCl) and high activity (maximum -25.1 mA/cm2 at -1.6 V vs Ag/AgCl) with a turnover number of 2.0 × 107. The CuT2 catalyst also showed excellent stability for 14 h of constant exposure to CH2Cl2 and 10 h of CH2Cl2 exposure cycling. The control compound, a copper-free triazole unit (T1), was also investigated under the same condition and showed inferior catalytic activity, indicating the importance of the copper center. Plausible catalytic mechanisms are proposed for the formation of C1 and C2 products via radical intermediates. Computational studies provided additional insight into the reaction mechanism and the selectivity toward the CH4 formation. The findings in this study demonstrate that complex CuT2 is an efficient and stable catalyst for the dehalogenation of CH2Cl2 and could potentially be used for the exploration of the removal of halogenated species from aqueous systems.
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Affiliation(s)
- Caroline K Williams
- Department of Chemistry, University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
| | - Gavin A McCarver
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996-1600, United States
| | - Amir Lashgari
- Department of Chemistry, University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
| | - Konstantinos D Vogiatzis
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996-1600, United States
| | - Jianbing Jimmy Jiang
- Department of Chemistry, University of Cincinnati, P.O. Box 210172, Cincinnati, Ohio 45221, United States
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