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Kulikova T, Maiorova A, Gorbunova T, Gulyaeva R, Safronov A, Pervova M. Chemical functionalization and thermal destruction of persistent organic pollutants: polychlorinated biphenyls. CHEMICAL PAPERS 2022. [DOI: 10.1007/s11696-022-02137-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Fujimori T, Ogura M, Eguchi A, Takaoka M. Dechlorination of short-chain chlorinated paraffins by the metal sodium dispersion method. CHEMOSPHERE 2021; 283:131201. [PMID: 34147973 DOI: 10.1016/j.chemosphere.2021.131201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/23/2021] [Accepted: 06/09/2021] [Indexed: 06/12/2023]
Abstract
Short-chain chlorinated paraffins (SCCPs) are listed in Annex A (elimination) of the Stockholm Convention on persistent organic pollutants, and products containing SCCPs require detoxification. In the present study, the metal sodium (Na) dispersion method was applied to a wax sample containing SCCPs (58%, C10-C13 and Cl5-Cl9) to assess the dechlorination effect. Effective dechlorination of SCCPs was confirmed using 2-L and 20-L reaction systems. The initial concentrations of the wax (5, 10, 20, 30%), reaction time (10, 30, 60, 120, 180 min), and the ratios of the amount of Na dispersion and the initial amount of the wax containing SCCPs (Na/wax ratios; 3.9, 4.4, 5.2) were tested. The destruction efficiency of SCCPs was over 99.999% after 10 min of reaction at 90 °C under several conditions. The initial concentrations of the wax and the Na/wax ratios did not affect the results. The ultralow SCCP contents in exhaust gas from the reaction tank demonstrated a destruction removal efficiency of over 99.999999%. Trace levels of polychlorinated dibenzo-p-dioxins and furans, dioxin-like polychlorinated biphenyls, hexachlorobenzene, and pentachlorobenzene in the wax sample and treated materials (oil, water, and gas) met various regulatory values or exhibited the same levels as the environmental background. After dechlorination of the SCCPs, the main reaction products in the reaction liquid and final oil phase were identified as aliphatic compounds. The metal Na dispersion method was found to be an effective and decontaminated destruction technique for application to SCCPs in liquid-like samples with no formation of hazardous organic byproducts.
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Affiliation(s)
- Takashi Fujimori
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Katsura, Nisikyo-ku, Kyoto, 615-8540, Japan; Faculty of Advanced Science and Technology, Ryukoku University, 1-5 Yokotani, Seta Oe-cho, Otsu, Shiga, 520-2194, Japan.
| | | | - Akifumi Eguchi
- Center for Preventive Medical Sciences, Chiba University, Chiba, 263-8522, Japan
| | - Masaki Takaoka
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Katsura, Nisikyo-ku, Kyoto, 615-8540, Japan
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Reductive degradation of 2,4-dichlorophenoxyacetic acid using Pd/carbon with bifunctional mechanism. Catal Today 2020. [DOI: 10.1016/j.cattod.2019.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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4
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Improvement of electrochemical reductive dechlorination of 2,4-dichlorophenoxyacetic acid using palladium catalysts prepared by a pulsed electrodeposition method. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2016.11.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kawano S, Kida T, Miyawaki K, Noguchi Y, Kato E, Nakano T, Akashi M. Cyclodextrin polymers as highly effective adsorbents for removal and recovery of polychlorobiphenyl (PCB) contaminants in insulating oil. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:8094-8100. [PMID: 24946276 DOI: 10.1021/es501243v] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A total of 179 countries (parties) ratified the Stockholm Convention on persistent organic pollutants (POPs) and agreed to destroy polychlorobiphenyls (PCBs) and develop a sound management plan by 2028. Currently, still 3 million tons of PCB-contaminated oil and equipment need to be managed under the Stockholm Convention. Thus, the development of a facile and environmentally benign method to treat large amounts of oil stockpiles contaminated with PCBs is a crucial subject. Herein, we report that cyclodextrin (CD) polymers, which are easily prepared by cross-linking the renewable cyclic oligosaccharide γ-cyclodextrin (γ-CD) with dibasic acid dichlorides, are a new selective and powerful adsorbent to remove PCB contaminants in oil. When PCB (100 ppm)-contaminated oil was passed through a column packed with the terephthaloyl-cross-linked γ-CD polymer (TP-γ-CD polymer) at 80-110 °C, the PCB contaminants were completely removed from the oil. Additionally, methyl esterification of the free carboxylic groups of the TP-γ-CD polymer enabled the complete recovery of the PCBs adsorbed on the polymer (with >99.9% recovery efficiency) by simply washing with acetone. The methyl-esterified TP-γ-CD polymer could be recycled at least 10 times for PCB adsorption without any loss in the adsorption capability. These results revealed that the γ-CD polymers can function as highly effective and powerful adsorbents for the removal and recovery of PCBs from PCB-contaminated oil and, thus, significantly contribute to the protection of the global environment.
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Affiliation(s)
- Shintaro Kawano
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University , 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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Zhang X, Yong G, She W. In Situ Demethoxylation, Dechloridation, or Decyanogenation from Coupling Aromatic Compounds Mediated by Potassium Metal. SYNTHETIC COMMUN 2013. [DOI: 10.1080/00397911.2012.744057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Zahran EM, Bhattacharyya D, Bachas LG. Reactivity of Pd/Fe bimetallic nanotubes in dechlorination of coplanar polychlorinated biphenyls. CHEMOSPHERE 2013; 91:165-71. [PMID: 23332879 PMCID: PMC4526161 DOI: 10.1016/j.chemosphere.2012.12.037] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 12/16/2012] [Indexed: 05/07/2023]
Abstract
A new class of bimetallic materials based on palladium-decorated iron nanotubes is described that demonstrates high reactivity in dechlorination reactions. This high dechlorination efficiency was attributed to the high surface area to volume ratio of the hollow nanotubes structure. Herein, we evaluated the effect of different conditions, such as the nanotube size, and the palladium loading on the efficiency of the dechlorination of PCB 77, a model coplanar polychlorinated biphenyl (PCB), by the Pd/Fe bimetallic nanotubes system. The efficiency of the dechlorination was lowered by decreasing the tube diameter from 200 to 100 nm. In addition, the interior surface as well as the exterior surface of the as-synthesized Pd/Fe bimetallic nanotubes was found to contribute to the high efficiency of the dechlorination of PCB 77. The dechlorination of PCB 77 by Pd/Fe bimetallic nanotubes demonstrated small activation energy indicating diffusion controlled reaction. The as-prepared Pd/Fe bimetallic nanotubes showed extended lifetime activity when used in multiple dechlorination cycles.
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Affiliation(s)
- Elsayed M. Zahran
- Department of Chemistry, University of Miami, Coral Gables, FL 33146
| | - Dibakar Bhattacharyya
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506
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KUROBOSHI M, IDEI H, HARA N, KOKUI Y, TANAKA H. Electroreduction of Aryl Halides Loaded on Palladium-Immobilized Activated Carbon. ELECTROCHEMISTRY 2013. [DOI: 10.5796/electrochemistry.81.359] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Wu BZ, Chen HY, Wang SJ, Wai CM, Liao W, Chiu K. Reductive dechlorination for remediation of polychlorinated biphenyls. CHEMOSPHERE 2012; 88:757-768. [PMID: 22572168 DOI: 10.1016/j.chemosphere.2012.03.056] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 03/06/2012] [Accepted: 03/18/2012] [Indexed: 05/31/2023]
Abstract
Technologies such as thermal, oxidative, reductive, and microbial methods for the remediation of polychlorinated biphenyls (PCBs) have previously been reviewed. Based on energy consumption, formation of PCDD/F, and remediation efficiency, reductive methods have emerged as being advantageous for remediation of PCBs. However, many new developments in this field have not been systematically reviewed. Therefore, reductive technologies published in the last decade related to remediation of PCBs will be reviewed here. Three categories, including catalytic hydrodechlorination with H(2), Fe-based reductive dechlorination, and other reductive dechlorination methods (e.g., hydrogen-transfer dechlorination, base-catalyzed dechlorination, and sodium dispersion) are specifically reviewed. In addition, the advantages of each remediation technology are discussed. In this review, 108 articles are referenced.
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Affiliation(s)
- Ben-Zen Wu
- Department of Chemistry, National Dong Hwa University, Hualien 97401, Taiwan, ROC
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Zhu K, Baig SA, Xu J, Sheng T, Xu X. Electrochemical reductive dechlorination of 2,4-dichlorophenoxyacetic acid using a palladium/nickel foam electrode. Electrochim Acta 2012. [DOI: 10.1016/j.electacta.2012.03.038] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Experimental and theoretical studies on synthesis and structure elucidation of some polychlorinated biphenyl derivatives. J Mol Struct 2010. [DOI: 10.1016/j.molstruc.2010.04.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Boyarskii VP, Sangaranarayanan MV, Khaibulova TS, Boyarskaya IA. Reduction of mono- and dichlorobiphenyls with sodium-naphthalene complex. RUSS J GEN CHEM+ 2010. [DOI: 10.1134/s1070363210040201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Sáez V, Esclapez MD, Tudela I, Bonete P, González-García J. Electrochemical Degradation of Perchloroethylene in Aqueous Media: Influence of the Electrochemical Operational Variables in the Viability of the Process. Ind Eng Chem Res 2010. [DOI: 10.1021/ie100134t] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Verónica Sáez
- Grupo de Nuevos Desarrollos Tecnológicos en Electroquímica: Sonoelectroquímica y Bioelectroquímica, Departamento de Química Física e Instituto Universitario de Electroquímica, Universidad de Alicante, Ap. Correos 99. 03080 Alicante, Spain
| | - Maria Deseada Esclapez
- Grupo de Nuevos Desarrollos Tecnológicos en Electroquímica: Sonoelectroquímica y Bioelectroquímica, Departamento de Química Física e Instituto Universitario de Electroquímica, Universidad de Alicante, Ap. Correos 99. 03080 Alicante, Spain
| | - Ignacio Tudela
- Grupo de Nuevos Desarrollos Tecnológicos en Electroquímica: Sonoelectroquímica y Bioelectroquímica, Departamento de Química Física e Instituto Universitario de Electroquímica, Universidad de Alicante, Ap. Correos 99. 03080 Alicante, Spain
| | - Pedro Bonete
- Grupo de Nuevos Desarrollos Tecnológicos en Electroquímica: Sonoelectroquímica y Bioelectroquímica, Departamento de Química Física e Instituto Universitario de Electroquímica, Universidad de Alicante, Ap. Correos 99. 03080 Alicante, Spain
| | - José González-García
- Grupo de Nuevos Desarrollos Tecnológicos en Electroquímica: Sonoelectroquímica y Bioelectroquímica, Departamento de Química Física e Instituto Universitario de Electroquímica, Universidad de Alicante, Ap. Correos 99. 03080 Alicante, Spain
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Choi H, Al-Abed SR, Agarwal S. Catalytic role of palladium and relative reactivity of substituted chlorines during adsorption and treatment of PCBs on reactive activated carbon. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:7510-7515. [PMID: 19848169 DOI: 10.1021/es901298b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The adsorption-mediated dechlorination of polychlorinated biphenyls (PCBs) is a unique feature of reactive activated carbon (RAC). Here, we address the RAC system, containing a tunable amount of Fe as a primary electron donor coupled with Pd as an electrochemical catalyst to potentially respond to the characteristic of contaminated sites, effectively traps and treats various PCB congeners. A dramatic increase in RAC reactivity with Pd doping at as low as 0.01% suggests its critical role for accelerating hydrodechlorination of PCBs. Characteristic adsorption and dechlorination behavior and ensuing decomposition pathways of 13 selected PCB congeners are discussed with their surface interactions with RAC. Important findings include (i) inherent dechlorination susceptibility of chlorines in para > meta > ortho position, regardless of independent or competitive conditions as well as substrate effects, (ii) favorable reduction of more toxic coplanar PCB congeners, (iii) preferential electrophilic attack to chlorines in a less substituted phenyl ring and an isolated chlorine, regardless of the steric or inductive effect as a dominant limiting factor for the dechlorination of ortho or meta PCBs, respectively, (iv) prominent dechlorination inhibition for higher ortho congeners but negligible inhibition for higher meta congeners, and (v) eventual complete dechlorination of higher PCB congeners to biphenyl.
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Affiliation(s)
- Hyeok Choi
- National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, Ohio 45268, USA
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Boyarskii VP, Zhesko TV, Lanina SA, Nikiforov VA, Tereshchenko GF. Catalytic carbonylation: A new process for recycling polychlorobiphenyls. CATALYSIS IN INDUSTRY 2009. [DOI: 10.1134/s2070050409030076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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17
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Wang JS, Chiu K. Destruction of pentachlorobiphenyl in soil by supercritical CO(2) extraction coupled with polymer-stabilized palladium nanoparticles. CHEMOSPHERE 2009; 75:629-633. [PMID: 19211124 DOI: 10.1016/j.chemosphere.2009.01.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Revised: 01/01/2009] [Accepted: 01/07/2009] [Indexed: 05/27/2023]
Abstract
PCBs exhibit a wide range of toxic effects, and they are very stable compounds and do not degrade readily. Although they had been banned in the 1970s; however; it is still urgent to investigate and develop a financially viable, environmentally benign and safe technology to treat the soils contaminated by PCBs. This study investigated the feasibility of coupling of supercritical fluid carbon dioxide (ScCO(2)) extraction with polymer-stabilized palladium nanoparticles for the destruction of pentachlorinated biphenyl (2,2',4,5,5'-PCB) from contaminated sand or soil samples. The extracted 2,2',4,5,5'-PCB can be converted into non-chlorinated products by hydrodechlorination catalyzed by palladium (Pd) nanoparticles, which were stabilized in high-density polyethylene (HDPE) beads. Nearly all 2,2',4,5,5'-PCB was removed quantitatively from solid matrices at 200atm and different temperatures. The final product was proved to be biphenyl and cyclohexylbenzene. The polymer-stabilized palladium nanoparticle catalyst, which does not contact the contaminated matrix directly, can be reused without losing the high catalytic activity inherent by nanometer-sized particles. Deactivation factors such as leaching of metal particles from support, agglomeration and sintering are minimized in this catalyst system due to the unique plastic matrix environment. A combination of supercritical fluid extraction and an on-line catalytic reaction system utilizing the plastic catalysts may have great advantages over other processes for destroying toxic chlorinated compounds in environmental samples.
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Affiliation(s)
| | - KongHwa Chiu
- Department of Applied Science, National Dong Hwa University, Hualien 970, Taiwan, ROC.
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Agarwal S, Al-Abed SR, Dionysiou DD, Graybill E. Reactivity of substituted chlorines and ensuing dechlorination pathways of select PCB congeners with Pd/Mg bimetallics. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:915-921. [PMID: 19245036 DOI: 10.1021/es802538d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Conflicting accounts occur on the reactivity of substituted chlorines and the ensuing dechlorination pathway of PCBs undergoing catalytic hydrodechlorination (HDCl). In order to understand these relationships, intermediates and dechlorination pathways of carefully selected 17 congeners were investigated with reactive Pd/Mg systems that bring about their rapid and complete dechlorination. The preferential site of electrophilic attack and its mechanistic aspects were interpreted in terms of steric, inductive, and resonance stabilization. The trends for electrophilic substitution were consistently p- > m- > o- positions indicating that more toxic "coplanar" PCB congeners were easily reduced. The dechlorination rates and pathways were influenced both by inductive effect of Cl that likely governs the stability of the intermediate arenium ion and by steric effects primarily effecting the adsorption step (especially for the o-congeners). Electrophilic attack occurred preferentially on the less substituted phenyl ring in absence of steric effects. A distinct correlation between rate of HDCl and the degree of chlorination was not observed, rather it depended on positions of Cl with respecttothe biphenyl bond, and the dominance between counteracting factors of deactivation by subsequent chlorinations and improvement in probability of dechlorination through increased number of Cls.
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Affiliation(s)
- Shirish Agarwal
- Department of Civil and Environmental Engineering, University of Cincinnati, Cincinnati, Ohio 45221-0071, USA
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Boyarskii VP, Zhesko TE, Lanina SA, Tereshchenko GF. Dechlorination of persistent organic pollutants polychlorobiphenyls by catalytic carbonylation. RUSS J APPL CHEM+ 2007. [DOI: 10.1134/s1070427207070154] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Liao W, Chen YC, Wang JS, Yak HK, Wai CM. Hydrodechlorination of Chlorinated Biphenyls in Supercritical CO2 Catalyzed by Polymer-Stabilized Palladium Nanoparticles. Ind Eng Chem Res 2007. [DOI: 10.1021/ie061562f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Weisheng Liao
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844, and Department of Chemistry, Chung-Yuan Christian University, Chung-Li, Taiwan, Republic of China
| | - Yun-Chieh Chen
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844, and Department of Chemistry, Chung-Yuan Christian University, Chung-Li, Taiwan, Republic of China
| | - Joanna S. Wang
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844, and Department of Chemistry, Chung-Yuan Christian University, Chung-Li, Taiwan, Republic of China
| | - Hwa Kwang Yak
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844, and Department of Chemistry, Chung-Yuan Christian University, Chung-Li, Taiwan, Republic of China
| | - Chien M. Wai
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844, and Department of Chemistry, Chung-Yuan Christian University, Chung-Li, Taiwan, Republic of China
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Noma Y, Mitsuhara Y, Matsuyama K, Sakai SI. Pathways and products of the degradation of PCBs by the sodium dispersion method. CHEMOSPHERE 2007; 68:871-9. [PMID: 17368509 DOI: 10.1016/j.chemosphere.2007.02.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Revised: 02/04/2007] [Accepted: 02/05/2007] [Indexed: 05/10/2023]
Abstract
Nine polychlorinated biphenyl (PCB) congeners (2-chlorobiphenyl, 3-chlorobiphenyl, 4-chlorobiphenyl, 2,3,4-trichlorobiphenyl, 2,2',5,5'-tetrachlorobiphenyl, 2,3',4,4',5-pentachlorobiphenyl, 3,3',4,4',5-pentachlorobiphenyl, 2,2',4,4',5,5'-hexachlorobiphenyl, and decachlorobiphenyl) were dechlorinated by the sodium dispersion method (SD) at low temperature (60 degrees C). The dechlorination of 4-chlorobiphenyl was the fastest among the three monochlorobiphenyls. As for the other six congeners, we investigated the major dechlorination pathways. Although reaction selectivity was not very sensitive to the position of the chlorine substituent, the chlorines at the para position were slightly easier to dechlorinate than those at the ortho or meta positions. The decomposition rate increased with the total numbers of chlorine substituents. A chlorine situated between two other chlorines showed a high reactivity. When the numbers of chlorines on each of the phenyl rings were different, the reactions occurred on the more substituted ring. In the degradation of 4-chlorobiphenyl at elevated temperature (160 degrees C), we investigated the structures of the polymerized products and whether all the organic chlorinated compounds degraded finally or not. As for the dimers, p-quarterphenyl (QP) and m,p-QP were detected but not o-QP, m-QP, o,p-QP, o,m-QP, or the mono- to tetra-chlorinated QPs. Compounds with a molecular weight of 534.4183 or 758.6713 were detected. They were considered to have C40H54 or C56H86 as their molecular formula. The compounds were most probably the polymerized products resulting from coupling of hexadecane or two hexadecanes and two phenylcyclohexadienes. It was thought the dechlorination and the polymerization were the main reactions. All of many detected compounds were hydrocarbons without chlorines, and no peaks originating from organic chlorinated compounds were observed by mass spectroscopic (MS) methods.
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Affiliation(s)
- Yukio Noma
- National Institute for Environmental Studies, 16-2, Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
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Sun Y, Takaoka M, Takeda N, Matsumoto T, Oshita K. Kinetics on the decomposition of polychlorinated biphenyls with activated carbon-supported iron. CHEMOSPHERE 2006; 65:183-9. [PMID: 16630644 DOI: 10.1016/j.chemosphere.2006.03.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2005] [Revised: 03/01/2006] [Accepted: 03/01/2006] [Indexed: 05/08/2023]
Abstract
The process of destroying polychlorinated biphenyls (PCBs) generates exhaust gases that contain low quantities of PCBs, which cannot be disposed of easily. Activated carbon (AC) can be used to adsorb residual PCBs after disposal of high-level PCBs. We examined the chemical reactivity of AC-supported iron as a catalyst to decompose PCB-153, and varied three decomposition parameters (temperature, time and iron concentration) under an atmosphere of either air or N(2). We measured the Brunauer-Emmett-Teller (BET) surface area and pore volume of AC to assess the adsorption capacity of AC before and after decomposition. At low temperatures the adsorption process was more important than the decomposition process. The decomposition process was completed within 30 and 60 min under air and N(2), respectively. The efficiency of PCB-153 decomposition at 350 degrees C for 120 min was approximately 100.0% and 97.1% under air and N(2), respectively. Analysis of inorganic chloride ions revealed that PCB-153 was effectively destroyed during decomposition. The differences between decomposition under air and N(2) reflected differences in BET surface and pore volume.
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Affiliation(s)
- Yifei Sun
- Department of Urban and Environmental Engineering, Graduate School of Engineering, Kyoto University, Yoshida-honmachi, Kyoto 606-8501, Japan
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Dechlorination of organohalogen compounds by an electrocatalytic cation supply system. J Electroanal Chem (Lausanne) 2004. [DOI: 10.1016/j.jelechem.2004.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Miyoshi K, Kamegaya Y, Matsumura M. Electrochemical reduction of organohalogen compound by noble metal sintered electrode. CHEMOSPHERE 2004; 56:187-193. [PMID: 15120565 DOI: 10.1016/j.chemosphere.2004.02.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2003] [Revised: 10/31/2003] [Accepted: 02/10/2004] [Indexed: 05/24/2023]
Abstract
1,2,3-Trichlorobenzene (1,2,3-TCB) was used as a model sample of persistent organic pollutants (POPs) which was dechlorinated by a closed electrochemical reduction system under an inert gas atmosphere. The effect of the electrode material was examined in the reaction. Dechlorination yields in different type of cathode electrodes using sintered RuO2 (major)/Pt/PdO, sintered Pt(major)/IrO2/RuO2, sintered RuO2, sintered PdO, sintered Pt, sintered PdO/Pt, sintered Pd/Pt and plain Pd plate were 91%, 81%, 59%, 96%, 53%, 97%, 82% and 70% respectively, at reaction times of 60 or 120 min. The reaction was exothermic after initially starting at room temperature. This electrochemical reduction system was friendly technology for environment using cation exchange membrane, supplying sodium ions from sodium hydroxide solution as anolyte. Trace amounts of dichlorobenzene, as products of stepwise dechlorination, were observed with different pathways, depending on the electrode material. Electrodes with Ru and Pd were selective mainly for meta-position dechlorination, while those with Pt groups selective mainly for ortho-position (o-position) dechlorination. A PdO sintered electrode had an especially high selectivity for meta-position (m-position) dechlorination. The results suggest that dechlorination is an electrocatalytic reduction in this cation supply system.
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Affiliation(s)
- Kumiko Miyoshi
- Institute of Applied Biochemistry, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-0006, Japan
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Miyoshi K, Nishio T, Yasuhara A, Morita M, Shibamoto T. Detoxification of hexachlorobenzene by dechlorination with potassium-sodium alloy. CHEMOSPHERE 2004; 55:1439-1446. [PMID: 15099723 DOI: 10.1016/j.chemosphere.2004.01.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2003] [Accepted: 01/08/2004] [Indexed: 05/24/2023]
Abstract
Dechlorination of hexachlorobenzene (HCB) was achieved by a liquid potassium-sodium (K-Na)-alloy. HCB in a cyclohexane/benzene solution (22 mmol/l, 4.67 g/l as chlorine) was dechlorinated by almost 100% after a 30-min reaction, indicating high reactivity of K-Na alloy and high proton donating power of cyclohexane. Decreasing orders of chlorobenzenes identified after a 15-min reaction, by amount were 1,2,3,4->1,2,3,5->1,2,4,5- for tetrachlorobenzenes, 1,2,4->1,2,3->1,3,5- for trichlorobenzenes, and 1,4->1,3->1,2- for dichlorobenzenes. It was hypothesized that once one chlorine atom in HCB was replaced with a proton, the adjacent chlorine atom to the proton tended to be replaced with another hydrogen atom. A total of 63 PCBs formed via the Wurtz-Fittig reaction were identified as by-products in the sample after a 15-min reaction. Among PCBs found, 2,3',4',5-tetrachlorobiphenyl, which was a product from 1,2,4-trichlorobenzene formed via the Wurtz-Fittig reaction, was detected in relatively high concentration (48.9 nmol/ml). The sample obtained from a reaction mixture after 30 min contained only 14 PCBs in trace amounts, indicating that the PCBs formed were also further dechlorinated by K-Na alloy. Non-chlorinated compounds--such as methylbenzene, dimethylbenzene, dimer of tetrahydrofuran, and dicyclohexyl (dimer of cyclohexane)--were also identified in the samples. A method using K-Na alloy developed in the present study dechlorinated satisfactorily HCB at room temperature.
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Affiliation(s)
- Kumiko Miyoshi
- Institute of Applied Biochemistry, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-0006, Japan
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Alonso F, Beletskaya IP, Yus M. Metal-mediated reductive hydrodehalogenation of organic halides. Chem Rev 2002; 102:4009-91. [PMID: 12428984 DOI: 10.1021/cr0102967] [Citation(s) in RCA: 607] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Francisco Alonso
- Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Alicante, Apdo 99, E-03080 Alicante, Spain
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