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Lei M, Tang Y, Zhu L, Tang H. Chemical reductive technologies for the debromination of polybrominated diphenyl ethers: A review. J Environ Sci (China) 2023; 127:42-59. [PMID: 36522073 DOI: 10.1016/j.jes.2022.05.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/06/2022] [Accepted: 05/10/2022] [Indexed: 06/17/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) are widely used as brominated flame retardants, which had attracted amounts of attention due to their harmful characteristics of high toxicity, environmental persistence and potential bioaccumulation. Many chemical reductive debromination technologies have been developed for the debromination of PBDEs, including photolysis, photocatalysis, electrocatalysis, zero-valent metal reduction, chemically catalytic reduction and mechanochemical method. This review aims to provide information about the degradation thermodynamics and kinetics of PBDEs and summarize the degradation mechanisms in various systems. According to the comparative analysis, the rapid debromination to generate bromine-free products in an electron-transfer process, of which photocatalysis is a representative one, is found to be relatively difficult, because the degradation rate of PBDEs depended on the Br-rich phenyl ring with the lowest unoccupied molecular orbital (LUMO) localization. On the contrary, the complete debromination occurs easily in other systems with active hydrogen atoms as the main reactive species, such as chemically catalytic reduction systems. The review provides the knowledge on the chemical reductive technique of PBDEs, which would greatly help not only clarify the degradation mechanism but also design the more efficient system for the rapid and deep debromination of PBDEs in the future.
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Affiliation(s)
- Ming Lei
- College of Resources and Environmental Science, South-Central Minzu University, Wuhan 430074, China
| | - Yao Tang
- College of Resources and Environmental Science, South-Central Minzu University, Wuhan 430074, China
| | - Lihua Zhu
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Heqing Tang
- College of Resources and Environmental Science, South-Central Minzu University, Wuhan 430074, China.
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2
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Dong J, Li G, Gao J, Zhang H, Bi S, Liu S, Liao C, Jiang G. Catalytic degradation of brominated flame retardants in the environment: New techniques and research highlights. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 848:157695. [PMID: 35908699 DOI: 10.1016/j.scitotenv.2022.157695] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/09/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
Due to the extensive commercial use of brominated flame retardants (BFRs), human beings are chronically exposed to BFRs, causing great harms to human health, which imposes urgent demands to degrade them in the environment. Among various degradation techniques, catalytic degradation has been proven to be outstanding because of its rapidness and effectiveness. Therefore, much attention has been given to catalytic degradation, especially the extensively studied photocatalytic degradation and nanocatalytic reduction techniques. Recently, some novel advanced catalytic techniques have been developed and show excellent catalytic degradation efficiency for BFRs, including natural substances catalytic degradation, new Fenton catalytic degradation, new chemical reagent catalytic degradation, new material catalytic degradation, electrocatalytic degradation, plasma catalytic degradation, and composite catalytic degradation systems. In addition to the common features of traditional catalytic techniques, these novel techniques possess their own specific advantages in various aspects. Therefore, this review summarized the degradation mechanism of BFRs by the above new catalytic degradation methods under the laboratory conditions, simulated real environment, and real environment conditions, and further evaluated their advantages and disadvantages, aiming to provide some research ideas for the catalytic degradation of BFRs in the environment in the future. We suggested that more attention should focus on features of novel catalytic techniques, including eco-friendliness, cost-effectiveness, and pragmatic usefulness.
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Affiliation(s)
- Jingcun Dong
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Guoliang Li
- College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China
| | - Jia Gao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - He Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Shihao Bi
- Neck-Shoulder and Lumbocrural Pain Hospital of Shandong First Medical University, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong 250062, China
| | - Sijin Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Chunyang Liao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
| | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of the Chinese Academy of Sciences, Beijing 100049, China
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Zhang X, Jia Q, Deng J, Wu F, Huang LZ. Interaction between green rust and tribromophenol under anoxic, oxic and anoxic-to-oxic conditions: Adsorption, desorption and oxidative degradation. WATER RESEARCH 2022; 217:118398. [PMID: 35413564 DOI: 10.1016/j.watres.2022.118398] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 03/27/2022] [Accepted: 03/31/2022] [Indexed: 06/14/2023]
Abstract
As a reductive Fe(II)-bearing mineral, green rust (GR) is able to reduce halogenated compounds in anoxic subsurface environments. The redox condition of subsurface environment often changes from anoxic to oxic due to natural and anthropogenic disturbances, but the interaction of GR with halogenated compounds in oxic, and anoxic-to-oxic transition conditions has not been studied. This study reveals that GR can sequester TBP for a short time (4 to 10 h) under anoxic conditions. Later, GR undergoes structural transformation to ferrihydrite and magnetite with the desorption of TBP. GR-derived iron (hydr)oxides can generate 33.8 μM of •OH upon 50 h exposure to dioxygen, which leads to 67% of oxidative degradation of TBP. The anoxic-to-oxic transition during the TBP adsorption process initiates the TBP desorption immediately, and also results in the oxidative degradation of TBP via the production of •OH. The oxygenation of GR immediately forms magnetite which activate dioxygen to produce •OH. Also, the GR-derived magnetite acts as a Fe(II) source, and free Fe(II) in solution and Fe(II) adsorbed on magnetite surface both contribute to dioxygen activation. This work provides vital evidence on the role of GR in the fate and transformation of TBP in redox alternating subsurface environments.
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Affiliation(s)
- Xuejie Zhang
- School of Civil Engineering, Wuhan University, No. 8, East Lake South Road, Wuhan, 430072, China; State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, 430072, China
| | - Qianqian Jia
- School of Civil Engineering, Wuhan University, No. 8, East Lake South Road, Wuhan, 430072, China; State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, 430072, China
| | - Jia Deng
- School of Civil Engineering, Wuhan University, No. 8, East Lake South Road, Wuhan, 430072, China; State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, 430072, China
| | - Feng Wu
- School of Resources and Environmental Science, Wuhan University, Wuhan, China
| | - Li-Zhi Huang
- School of Civil Engineering, Wuhan University, No. 8, East Lake South Road, Wuhan, 430072, China; State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, 430072, China.
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4
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Martin ET, McGuire CM, Mubarak MS, Peters DG. Electroreductive Remediation of Halogenated Environmental Pollutants. Chem Rev 2016; 116:15198-15234. [DOI: 10.1021/acs.chemrev.6b00531] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Erin T. Martin
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Caitlyn M. McGuire
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | | | - Dennis G. Peters
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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5
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Santos MSF, Alves A, Madeira LM. Chemical and photochemical degradation of polybrominated diphenyl ethers in liquid systems - A review. WATER RESEARCH 2016; 88:39-59. [PMID: 26465809 DOI: 10.1016/j.watres.2015.09.044] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 07/24/2015] [Accepted: 09/27/2015] [Indexed: 06/05/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) are brominated flame retardants which have received a great deal of attention due to their persistence, potential to bioaccumulate and possible toxic effects. PBDEs have been globally detected in humans, wildlife and environment, highlighting the urgency of looking for effective removal technologies to mitigate their spread and accumulation in the environment. Among all environmental compartments, the water has raised particular attention. This paper aims to provide information about the suitability of the main degradation processes investigated to date (photolysis, zerovalent iron and TiO2 photocatalysis) for the degradation of PBDEs in water matrices. The most relevant criteria behind the design of a system for such purpose are discussed in detail for each individual process. The comparative analysis suggests that the oxidative degradation by TiO2 is the most appropriated technology to treat waters contaminated with PBDEs because higher debromination and mineralization degrees are achieved, preventing the formation/accumulation of lower brominated PBDE congeners and promoting the cracking of aromatic cores.
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Affiliation(s)
- Mónica S F Santos
- LEPABE - Laboratory for Process, Environmental, Biotechnology and Energy Engineering, Faculty of Engineering, University of Porto, R. Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal.
| | - Arminda Alves
- LEPABE - Laboratory for Process, Environmental, Biotechnology and Energy Engineering, Faculty of Engineering, University of Porto, R. Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
| | - Luis M Madeira
- LEPABE - Laboratory for Process, Environmental, Biotechnology and Energy Engineering, Faculty of Engineering, University of Porto, R. Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal.
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6
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Photochemical degradation of polybrominated diphenyl ethers in microreactor. RESEARCH ON CHEMICAL INTERMEDIATES 2015. [DOI: 10.1007/s11164-015-2033-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/29/2022]
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Vesely M, Vajglova Z, Kotas P, Kristal J, Ponec R, Jiricny V. Model for photodegradation of polybrominated diphenyl ethers. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:4949-4963. [PMID: 25345925 DOI: 10.1007/s11356-014-3741-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 10/17/2014] [Indexed: 06/04/2023]
Abstract
Polybrominated diphenyl ethers (PBDE) were, and in some countries still are, used as flame retardants for plastic materials. When released from plastics, PDBE cause harm to the environment. This creates the incentive for further investigation of the PBDE degradation. This work focused on a formulation of a PBDE photodegradation model based on the PBDE properties obtained by the quantum chemical calculations. The proposed model predicted degradation routes of arbitrary PBDE congener. The routes of selected congeners were validated by the two independently published data sets and showed the high fitting degree. The model can be easily modified for any reactor system if the initial reaction rate constant of one congener is available for the given system.
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Affiliation(s)
- M Vesely
- Institute of Chemical Process Fundamentals, AS CR, v. v. i., Rozvojova 135, 165 02, Prague 6, Czech Republic
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8
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Rotko G, Romańczyk PP, Kurek SS. Reductive debromination of decabromodiphenyl ether yields brominated dibenzofurans in a Pschorr-type cyclisation. Electrochem commun 2013. [DOI: 10.1016/j.elecom.2013.10.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Peverly AA, Pasciak EM, Strawsine LM, Wagoner ER, Peters DG. Electrochemical reduction of decabromodiphenyl ether at carbon and silver cathodes in dimethylformamide and dimethyl sulfoxide. J Electroanal Chem (Lausanne) 2013. [DOI: 10.1016/j.jelechem.2013.07.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Cao H, He M, Han D, Li J, Li M, Wang W, Yao S. OH-initiated oxidation mechanisms and kinetics of 2,4,4'-Tribrominated diphenyl ether. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:8238-8247. [PMID: 23855483 DOI: 10.1021/es400088v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
2,4,4'-Tribromodiphenyl ether (BDE-28) was selected as a typical congener of polybrominated diphenyl ethers (PBDEs) to examine its fate both in the atmosphere and in water solution. All the calculations were obtained at the ground state. The mechanism result shows that the oxidations between BDE-28 and OH radicals are highly feasible especially at the less-brominated phenyl ring. Hydroxylated dibrominated diphenyl ethers (OH-PBDEs) are formed through direct bromine-substitution reactions (P1∼P3) or secondary reactions of OH-adducts (P4∼P8). Polybrominated dibenzo-p-dioxins (PBDDs) resulting from o-OH-PBDEs are favored products compared with polybrominated dibenzofurans (PBDFs) generated by bromophenols and their radicals. The complete degradation of OH adducts in the presence of O2/NO, which generates unsaturated ketones and aldehydes, is less feasible compared with the H-abstraction pathways by O2. Aqueous solution reduces the feasibility between BDE-28 and the OH radical. The rate constant of BDE-28 and the OH radical is determined to be 1.79 × 10(-12) cm(3) molecule(-1) s(-1) with an atmospheric lifetime of 6.7 days.
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Affiliation(s)
- Haijie Cao
- Environment Research Institute, Shandong University, Jinan 250100, PR China
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11
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Sun C, Chang W, Ma W, Chen C, Zhao J. Photoreductive debromination of decabromodiphenyl ethers in the presence of carboxylates under visible light irradiation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:2370-2377. [PMID: 23383645 DOI: 10.1021/es3045604] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) have aroused global environmental concerns because of their toxicity and ubiquitousness in the biological and environmental systems. It is important to find an efficient method for their decontamination and to understand their chemical transformation in the environment. Here, we report that decabromodiphenyl ether (BDE209) undergoes efficient reductive debromination reactions under visible-light irradiation (≥ 420 nm) in the presence of various carboxylate anions that are common in the environmental media. The debromination reactions occur in a stepwise manner, producing a series of lower brominated PBDE congeners. Solvent-derived radials are observed by spin-trapping electron spin resonance (ESR) experiments during the photoreaction. Further experiments by the UV-vis absorption and isothermal titration calorimetry (ITC), combined with theoretical calculations, reveal a new photochemical debromination pathway based on the halogen binding interaction. According to this pathway, the formation of halogen-binding-based complex between PBDE and carboxylate enables the visible-light absorption and debromination of PBDEs, although neither PBDEs nor carboxylates have visible-light absorption. The halogen-bond-based photochemical debromination could find its application for our better understanding of the transformation process of PBDEs in the environment.
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Affiliation(s)
- Chunyan Sun
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China
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Luo S, Yang S, Xue Y, Liang F, Sun C. Two-stage reduction/subsequent oxidation treatment of 2,2',4,4'-tetrabromodiphenyl ether in aqueous solutions: kinetic, pathway and toxicity. JOURNAL OF HAZARDOUS MATERIALS 2011; 192:1795-1803. [PMID: 21807460 DOI: 10.1016/j.jhazmat.2011.07.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Revised: 05/29/2011] [Accepted: 07/04/2011] [Indexed: 05/31/2023]
Abstract
The effectiveness of a two-stage reduction/subsequent oxidation (T-SRO) treatment of BDE-47, consisting of Fe-Ag reduction and Fenton-like oxidation, was investigated in this study. As an oxidation-resisting pollutant, BDE-47 (5 mg L(-1)) was difficult to be degraded by homogeneous Fe-Ag/H(2)O(2) system coupled with ultrasound (US) in 30 min. However, when this solution was firstly treated with Fe-Ag/US, the final debrominated product could be rapidly oxidized by the succeeding Fenton-like reactions, resulting in an efficient debromination of BDE-47 and a 100% mineralization of diphenyl ether (DPE). To scrutinize the degradation mechanism, several analytical techniques including HPLC, LC-MS/MS and GC/MS, were employed to monitor the major intermediates and final products. Moreover, luminescent bacteria test showed that the acute toxicity of the original solution (before reduction) was evidently lower than that of Fe-Ag/US reduction-treated solution; no toxicity was detected after Fenton-like oxidation. Evidence for the significance of a T-SRO treatment to decompose BDE-47 was presented.
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Affiliation(s)
- Si Luo
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China
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Li MC, Bao DD, Ma CA. Studies on electrochemical hydrodebromination mechanism of 2,5-dibromobenzoic acid on Ag electrode by in situ FTIR spectroscopy. Electrochim Acta 2011. [DOI: 10.1016/j.electacta.2011.01.115] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Granelli L, Eriksson J, Athanasiadou M, Bergman Å. Reductive debromination of nonabrominated diphenyl ethers by sodium borohydride and identification of octabrominated diphenyl ether products. CHEMOSPHERE 2011; 82:839-846. [PMID: 21122890 DOI: 10.1016/j.chemosphere.2010.11.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 11/03/2010] [Accepted: 11/05/2010] [Indexed: 05/30/2023]
Abstract
A method was developed to study reductive transformation of highly brominated diphenyl ethers (BDEs). The method development is a part of a broader project where it will be used to determine the susceptibility of environmental pollutants to reductive conditions, in an attempt to create a scheme for determination of chemical's persistence. This paper focuses on identification of octabrominated diphenyl ether transformation products from reductive debromination of the three nonabrominated diphenyl congeners (nonaBDE), BDE-206, -207 and -208. Sodium borohydride was used to explore the reductive debromination of the nonaBDEs. The transformation products were collected at two time-points and identified products were quantified by GC-MS. The reduction of the nonaBDEs lead primarily to debrominated products, mainly octaBDEs. The three nonabrominated DEs gave isomer-related transformation product patterns. BDE-207 and BDE-208 showed a propensity for ortho-debromination in the initial reaction step, while no discrimination between initial debromination positions was seen for BDE-206. All three nonabrominated DEs displayed a preferred initial debromination on the fully brominated DE ring.
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Affiliation(s)
- Lisa Granelli
- Environmental Chemistry Unit, Department of Materials and Environmental Chemistry, Stockholm University, SE-10691 Stockholm, Sweden.
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15
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Wang D, Li QX. Application of mass spectrometry in the analysis of polybrominated diphenyl ethers. MASS SPECTROMETRY REVIEWS 2010; 29:737-775. [PMID: 19722247 DOI: 10.1002/mas.20263] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This review summarized the applications of mass spectrometric techniques for the analysis of the important flame retardants polybrominated diphenyl ethers (PBDEs) to understand the environmental sources, fate and toxicity of PBDEs that were briefly discussed to give a general idea for the need of analytical methodologies. Specific performance of various mass spectrometers hyphenated with, for example, gas chromatograph, liquid chromatograph, and inductively coupled plasma (GC/MS, LC/MS, and ICP/MS, respectively) for the analysis of PBDEs was compared with an objective to present the information on the evolution of MS techniques for determining PBDEs in environmental and human samples. GC/electron capture negative ionization quadrupole MS (GC/NCI qMS), GC/high resolution MS (GC/HRMS) and GC ion trap MS (GC/ITMS) are most commonly used MS techniques for the determination of PBDEs. New analytical technologies such as fast tandem GC/MS and LC/MS become available to improve analyses of higher PBDEs. The development and application of the tandem MS techniques have helped to understand environmental fate and transformations of PBDEs of which abiotic and biotic degradation of decaBDE is thought to be one major source of Br(1-9)BDEs present in the environment in addition to direct loading from commercial mixtures. MS-based proteomics will offer an insight into the molecular mechanisms of toxicity and potential developmental and neurotoxicity of PBDEs.
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Affiliation(s)
- Dongli Wang
- Department of Molecular Biosciences and Bioengineering, University of Hawaii, Honolulu, Hawaii 96822, USA
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16
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Liu GB, Zhao HY, Yang B, Thiemann T. Zinc dust-mediated reductive degradation of decabromodiphenyl ether. GREEN CHEMISTRY LETTERS AND REVIEWS 2010; 3:1-6. [DOI: 10.1080/17518250903393882] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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17
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Davis EF, Stapleton HM. Photodegradation pathways of nonabrominated diphenyl ethers, 2-ethylhexyltetrabromobenzoate and di(2-ethylhexyl)tetrabromophthalate: identifying potential markers of photodegradation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:5739-46. [PMID: 19731671 DOI: 10.1021/es901019w] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Photodegradation kinetics of several polybrominated diphenyl ethers (PBDEs), particularly decabromodiphenyl ether (BDE 209), have been reported in various matrixes, demonstrating that it photodegrades primarily via debromination. However, it has been difficult to determine the primary pathways by which bromine is cleaved from BDE 209 to form nona- and octabrominated congeners. In this study, photodegradation of the three nonaBDE congeners (i.e., BDE 206, 207, and 208) was examined individually in three different solvents exposed to natural sunlight and then analyzed to identify the primary degradation products. Rapid degradation of nonaBDEs (half-lives ranging from 4.25 to 12.78 min) was observed coincident with formation of octa- and heptabrominated PBDEs. BDE 207 photodegraded most rapidly while BDE 206 photodegraded the slowest. The photodegradation pathways of each nonaBDE congener were consistent among the different solvent matrixes tested; however, mass balances were found to vary with the type of solvent used in the experiment (recovery ranging from 76 to 95%). The octabrominated congener, BDE 202, and the ratio of BDE197 to BDE 201,were identified as congeners that may serve as environmental markers of photolytic debromination of decaBDE. Additional photodegradation studies were conducted with two new brominated flame retardants used in replacements for pentaBDE mixtures: 2-ethylhexyltetrabromobenzoate (TBB) and di(2-ethylhexyl)-tetrabromophthalate (TBPH). Both TBB and TBPH underwent photolysis more slowly than nonaBDEs (half-lives ranging from 85.70 to 220.17 min) and primarily formed debrominated products.
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Affiliation(s)
- Elizabeth F Davis
- Duke University, Nicholas School of the Environment, Durham, North Carolina 27708, USA
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