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Lastre-Acosta AM, Rocha CM, Mendes MA, Teixeira ACSC, do Nascimento CAO. Sunlight-driven environmental photodegradation of 2-chlorobiphenyl (PCB-1) in surface waters: kinetic study and mathematical simulations. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:42231-42241. [PMID: 34677777 DOI: 10.1007/s11356-021-17010-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 10/08/2021] [Indexed: 06/13/2023]
Abstract
Polychlorinated biphenyls (PCBs) are a family of highly toxic, resistant, and persistent organic pollutants, among which 2-chlorobiphenyl (PCB-1) is one of the simplest. Most studies on PCBs' photochemistry are limited to their direct photolysis, while the important role of reactive photo-induced species (RPS) (hydroxyl radicals, HO●; singlet oxygen, 1O2; and triplet excited states of chromophoric dissolved organic matter, 3CDOM*) in removing PCBs in natural waters through indirect photolysis has not yet been evaluated. In this work, the rate constants of the reactions between aqueous PCB-1 and RPS were obtained under simulated solar radiation (450-W Xenon lamp and an AM 1.5 global filter) by competition kinetics, and the effects of the initial pollutant concentration and the physicochemical characteristics of the water were investigated. The direct photolysis quantum yield of PCB-1 in the range 290-800 nm was found as 1.60 × 10-2 mol Einstein-1. The value of kPCB-1,HO● = (6.80 ± 0.09) × 109 L mol-1 s-1 is in good agreement with the literature. For 1O2, kPCB-1,1O2 = (1.13 ± 0.20) × 106 L mol-1 s-1, while for 3CDOM*, kPCB-1,3CBBP* = (2.44 ± 0.04) × 109 L mol-1 s-1 and kPCB-1,3AQ2S* = (3.36 ± 0.04) × 109 L mol-1 s-1 were obtained using 4-benzoylbenzoic acid (CBBP) and anthraquinone-2-sulfonate (AQ2S) as CDOM proxies, respectively. These results show that the main pathways involved in PCB-1 photodegradation are the reactions with HO● and 3CDOM* together with direct photolysis. In addition, the photodegradation of PCB-1 in sunlit waters was simulated using the kinetic model APEX (Aqueous Photochemistry of Environmentally Occurring Xenobiotics). According to simulations, a greater influence of the water depth and dissolved organic carbon concentration (DOC) on the persistence of PCB-1 is expected, being only slightly influenced by the concentrations of nitrite, nitrate, and bicarbonate. Finally, based on data reported for Brazilian surface waters, the average half-life (t1/2) of PCB-1 is expected to vary from 2 to 14 days. In particular, the t1/2 in the Paranapanema River is estimated at 7 to 8 days.
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Affiliation(s)
- Arlen Mabel Lastre-Acosta
- Research Group in Advanced Oxidation Processes (AdOx), Chemical Systems Engineering Center, Department of Chemical Engineering, University of São Paulo, Av. Prof. Luciano Gualberto, tr. 3, 380, São Paulo, SP, Brazil.
| | - Carolina Mendes Rocha
- Research Group in Advanced Oxidation Processes (AdOx), Chemical Systems Engineering Center, Department of Chemical Engineering, University of São Paulo, Av. Prof. Luciano Gualberto, tr. 3, 380, São Paulo, SP, Brazil
| | - Maria Anita Mendes
- Dempster MS Lab, Chemical Systems Engineering Center, Department of Chemical Engineering, University of Sao Paulo, Av. Prof. Luciano Gualberto, tr. 3, 380, São Paulo, SP, Brazil
| | - Antonio Carlos Silva Costa Teixeira
- Research Group in Advanced Oxidation Processes (AdOx), Chemical Systems Engineering Center, Department of Chemical Engineering, University of São Paulo, Av. Prof. Luciano Gualberto, tr. 3, 380, São Paulo, SP, Brazil
| | - Claudio Augusto Oller do Nascimento
- Dempster MS Lab, Chemical Systems Engineering Center, Department of Chemical Engineering, University of Sao Paulo, Av. Prof. Luciano Gualberto, tr. 3, 380, São Paulo, SP, Brazil
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Lee D, Son Y. Ultrasound-assisted soil washing processes using organic solvents for the remediation of PCBs-contaminated soils. ULTRASONICS SONOCHEMISTRY 2021; 80:105825. [PMID: 34775161 PMCID: PMC8593648 DOI: 10.1016/j.ultsonch.2021.105825] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 10/20/2021] [Accepted: 11/03/2021] [Indexed: 05/12/2023]
Abstract
Ultrasonic soil washing processes using organic solvents were investigated for the development of novel remediation technologies for persistent organic pollutants (POPs)- contaminated soils. Aluminum foil erosion was first tested to understand sonophysical activity in water, methanol (polar) and n-hexane (nonpolar) in a 28 kHz double-bath-type sonoreactor. Significant sonophysical damage on the aluminum foil was observed at the antinodes for all solvents, and the order of degree of sonophysical damage was as follows: water > methanol > n-hexane. Subsequently, conventional (mechanical mixing only) and ultrasonic soil washing (mechanical mixing and ultrasound) techniques were compared for the removal of polychlorinated biphenyls (PCBs) from soil. Two types of contaminated soils, fresh (Soil A, C0 = 2.5 mg/kg) and weathered (Soil B, C0 = 0.5 mg/kg), were used and the applied soil-to-liquid (S:L) ratio was 1:5 and 1:10 for methanol and n-hexane, respectively. The polar solvent significantly increased washing efficiencies compared to the nonpolar solvent, despite the nonpolar nature of the PCBs. Washing efficiency was significantly enhanced in ultrasonic soil washing compared to conventional washing, owing to macro- and micro-scale sonophysical actions. The highest washing efficiencies of 90% for Soil A and 70% for Soil B were observed in the ultrasonic washing processes using methanol. Additionally, a single operation of the ultrasonic washing process was superior to two sequential processes with conventional mixing in terms of washing efficiency, consumption of washing agents, treatment of washing leachate, and operation time. Finally, the removal of PCBs in an organic solvent (methanol) was investigated in photolytic and sonolytic processes for the post-treatment of soil washing leachate. A photolysis efficiency of 80% was obtained within 60 min of UV exposure for intensities of 1.0, 2.0, and 4.0 W/cm2. The primary mechanism of PCBs degradation is photolytic dechlorination. In contrast, no degradation was detected in the sonolytic process, as the excess organic solvent acted as a strong radical scavenger.
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Affiliation(s)
- Dukyoung Lee
- Department of Environmental Engineering, Kumoh National Institute of Technology, Gumi 39177, Republic of Korea; Department of Energy Engineering Convergence, Kumoh National Institute of Technology, Gumi 39177, Republic of Korea
| | - Younggyu Son
- Department of Environmental Engineering, Kumoh National Institute of Technology, Gumi 39177, Republic of Korea; Department of Energy Engineering Convergence, Kumoh National Institute of Technology, Gumi 39177, Republic of Korea.
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Li M, He W, Yang H, Sun S, Li Y. Potential Environmental Risk Characteristics of PCB Transformation Products in the Environmental Medium. TOXICS 2021; 9:toxics9090213. [PMID: 34564364 PMCID: PMC8472189 DOI: 10.3390/toxics9090213] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/02/2021] [Accepted: 09/03/2021] [Indexed: 11/16/2022]
Abstract
The complementary construction of polychlorinated biphenyl (PCB) phytotoxicity and the biotoxicity 3D-QSAR model, combined with the constructed PCB environmental risk characterization model, was carried out to evaluate the persistent organic pollutant (POP) properties (toxicity (phytotoxicity and biotoxicity), bioconcentration, migration, and persistence) of PCBs and their corresponding transformation products (phytodegradation, microbial degradation, biometabolism, and photodegradation). The transformation path with a significant increase in environmental risks was analyzed. Some environmentally friendly PCB derivatives, exhibiting a good modification effect, and their parent molecules were selected as precursor molecules. Their transformation processes were simulated and evaluated for assessing the environmental risks. Some transformation products displayed increased environmental risks. The environmental risks of plant degradation products of the PCBs in the environmental media showed the maximum risk, indicating that the potential risks of the transformation products of the PCBs and their environmentally friendly derivatives could not be neglected. It is essential to further improve the ability of plants to degrade their transformation products. The improvement of some degradation products for environmentally friendly PCB derivatives indicates that the theoretical modification of a single environmental feature cannot completely control the potential environmental risks of molecules. In addition, this method can be used to analyze and evaluate environmentally friendly PCB derivatives to avoid and reduce the potential environmental and human health risks caused by environmentally friendly PCB derivatives.
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Affiliation(s)
- Minghao Li
- The Moe Key Laboratory of Resources and Environmental Systems Optimization, North China Electric Power University, Beijing 102206, China; (M.L.); (W.H.); (H.Y.)
- School of Emergency Science and Engineering, Jilin Jianzhu University, Changchun 130119, China
| | - Wei He
- The Moe Key Laboratory of Resources and Environmental Systems Optimization, North China Electric Power University, Beijing 102206, China; (M.L.); (W.H.); (H.Y.)
| | - Hao Yang
- The Moe Key Laboratory of Resources and Environmental Systems Optimization, North China Electric Power University, Beijing 102206, China; (M.L.); (W.H.); (H.Y.)
| | - Shimei Sun
- School of Emergency Science and Engineering, Jilin Jianzhu University, Changchun 130119, China
- Correspondence: (S.S.); (Y.L.)
| | - Yu Li
- The Moe Key Laboratory of Resources and Environmental Systems Optimization, North China Electric Power University, Beijing 102206, China; (M.L.); (W.H.); (H.Y.)
- Correspondence: (S.S.); (Y.L.)
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Huang C, Zeng Y, Luo X, Ren Z, Tian Y, Mai B. Comprehensive exploration of the ultraviolet degradation of polychlorinated biphenyls in different media. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 755:142590. [PMID: 33059143 DOI: 10.1016/j.scitotenv.2020.142590] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 06/11/2023]
Abstract
As one of the most important natural transformation processes, photodegradation deserves more attention and research. In the current work, we comprehensively explored the photochemical behaviors of polychlorinated biphenyls (PCBs) in n-hexane (Hex), methanol/water, and silica gel under UV-irradiation. Photodegradation rates were found to be faster in methanol/water than in Hex. All of the three photochemical systems generated sigmatropic rearrangement products. The dominant photodegradation pathways were dechlorination, dechlorination/methoxylation/hydroxylation, and hydroxylation in Hex, methanol/water, and silica gel systems, respectively. Furthermore, some new photodegradation products, such as polychlorinated biphenyl ethers, polychlorinated dibenzofurans, polychlorinated biphenylenes, and methylated polychlorinated biphenyls, are reported for the first time. These findings would provide deeper insight into the phototransformation behaviors of PCBs.
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Affiliation(s)
- Chenchen Huang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanhong Zeng
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
| | - Xiaojun Luo
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Zihe Ren
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yankuan Tian
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Bixian Mai
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
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Huang Q, Fang C. Degradation of 3,3',4,4'-tetrachlorobiphenyl (PCB77) by dielectric barrier discharge (DBD) non-thermal plasma: Degradation mechanism and toxicity evaluation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 739:139926. [PMID: 32540661 DOI: 10.1016/j.scitotenv.2020.139926] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 06/01/2020] [Accepted: 06/01/2020] [Indexed: 06/11/2023]
Abstract
Polychlorinated biphenyls (PCBs) are a kind of persistent organic pollutants (POPs) with stable chemical properties which can be enriched in a biological body for a long time. They are often carelessly released into natural environment and thus constantly posing a potential threat to human health. However, because of lack of effective ways of degrading PCBs, researchers are still striving to explore new approaches to remove them from the environment. In this work, we employed atmospheric-pressure non-thermal dielectric barrier discharge (DBD) plasma to treat 3,3',4,4'-tetrachlorobiphenyl (PCB77) in aqueous solution and investigated the removal efficiency under different DBD conditions using different discharging gases. As a result, we showed that He-DBD had the highest removal efficiency with hydroxyl radical playing the major role in the degradation, while O2-DBD also gave rise to relatively high efficiency with ozone making an important contribution. After 2 min of treatments by He-DBD and O2-DBD, over 75% of PCB77 was degraded with removal rate of 23.65 mg/L and 22.19 mg/L per minute, respectively. Besides, the toxicological evaluation for the DBD treatment was also provided, confirming that the PCB77 degradation products had negligible biotoxicity. This work therefore provides a new effective approach to treatment of persistent organic pollutants (POPs) in the environment.
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Affiliation(s)
- Qing Huang
- CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Institute of Intelligent Machines, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China; Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, China.
| | - Cao Fang
- CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Institute of Intelligent Machines, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China; Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, China
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Khammar S, Bahramifar N, Younesi H. Preparation and surface engineering of CM-β-CD functionalized Fe 3O 4@TiO 2 nanoparticles for photocatalytic degradation of polychlorinated biphenyls (PCBs) from transformer oil. JOURNAL OF HAZARDOUS MATERIALS 2020; 394:122422. [PMID: 32200245 DOI: 10.1016/j.jhazmat.2020.122422] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 06/10/2023]
Abstract
The aim of the present research is to investigate the efficiency of surface-modified magnetic nanoparticles for photocatalytic degradation of PCBs from transformer oil. Therefore, CMCD-Fe3O4@TiO2 was successfully produced via grafting of carboxymethyl-β-cyclodextrin (CM-β-CD) onto the core-shell titania magnetic nanoparticles surface. The photocatalytic efficiency of CMCD-Fe3O4@TiO2 for degradation of PCBs was systematically evaluated using an experimental design and the process parameters were optimized by response surface methodology (RSM). The central composite design (CCD) with four experimental parameters was used successfully in the modeling and optimization of photocatalytic efficiency in removing PCBs from transformer oil. ANOVA analysis confirmed a high R-squared value of 0.9769 describing the goodness of fit of the proposed model for the significance estimation of the individual and the interaction effects of variables. The optimal degradation yields of PCBs was achieved 83 % at a temperature of 25 °C, time of 16 min, the dosage of the catalyst of 8.35 mg and oil: ethanol ratio of 1:5. These findings encourage the practical use of CM-β-CD-Fe3O4@TiO2 as a promising and alternative photocatalyst on an industrial scale for the cleaning of organic pollutants such as PCBs due to its environmental friendliness, the benefit of magnetic separation and good reusability after five times.
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Affiliation(s)
- Sanaz Khammar
- Department of Environmental Sciences, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, P.O. Box 46414-356 Nour, Mazandaran, Iran
| | - Nader Bahramifar
- Department of Environmental Sciences, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, P.O. Box 46414-356 Nour, Mazandaran, Iran.
| | - Habibollah Younesi
- Department of Environmental Sciences, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, P.O. Box 46414-356 Nour, Mazandaran, Iran
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Jalili-Jahani N, Fatehi A, Zeraatkar E. PLS and N-PLS based MIA-QSPR modeling of the photodegradation half-lives for polychlorinated biphenyl congeners. RSC Adv 2020; 10:33753-33761. [PMID: 35519039 PMCID: PMC9056733 DOI: 10.1039/d0ra05231k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 07/27/2020] [Indexed: 11/21/2022] Open
Abstract
Multivariate image analysis as a useful tool in environmental risk assessment studies.
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Affiliation(s)
| | - Azadeh Fatehi
- Green Land Shiraz Eksir Chemical and Agricultural Industries Company
- Shiraz
- Iran
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Eker G, Hatipoglu M. Effect of UV wavelength, temperature and photocatalyst on the removal of PAHs from industrial soil with photodegradation applications. ENVIRONMENTAL TECHNOLOGY 2019; 40:3793-3803. [PMID: 29927727 DOI: 10.1080/09593330.2018.1491635] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 06/07/2018] [Indexed: 06/08/2023]
Abstract
The aim of the present study was to evaluate the effectiveness of UV-based processes to the removal of PAHs from soils with and without photocatalyst. PAH removal experiments were conducted in a specially designed UV photochamber. The effects of various factors, namely temperature, light wavelength (UVA, UVC), TiO2 dose on the removal of PAHs were examined. Furthermore, evaporation ratios of PAHs during UV applications were determined with polyurethane foam (PUF) samples. Temperature increase positively affected PAH removal process. The total 12 (∑12) PAH content reduced by 86-90% in the soil samples during UV applications. With the use of UVA rays, higher ∑12 PAH removal was enhanced when compared to UVC rays. It was thought that in the existence of UVC rays, other aromatic compounds or other PAHs in soil converted to targeted PAHs with photodegradation. The amounts of evaporated PAHs from soil were increased with increasing of temperature and more than 90% of PAHs in the air consisted of 3-4 ring compounds. It was found that TiO2 provided an increase in removal ratios and ∑12 PAHs removal ratios changed between 87% and 94%. Furthermore, the amount of PAH migrated to the air decreased during this application. During UVA-TiO2 and UVC-TiO2 applications, at 30°C, evaporated average ∑12 PAH amounts were 2.91 ng/m3 and 6.59 ng/m3, respectively.
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Affiliation(s)
- Gizem Eker
- Department of Environmental Engineering, Faculty of Engineering, Uludag University, Bursa, Turkey
| | - Melis Hatipoglu
- Department of Environmental Engineering, Faculty of Engineering, Uludag University, Bursa, Turkey
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Dabić D, Babić S, Škorić I. The role of photodegradation in the environmental fate of hydroxychloroquine. CHEMOSPHERE 2019; 230:268-277. [PMID: 31108437 DOI: 10.1016/j.chemosphere.2019.05.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 04/18/2019] [Accepted: 05/04/2019] [Indexed: 05/23/2023]
Abstract
For many organic pollutants present in surface waters, photolysis is considered as a major abiotic degradation process. The present study aimed to explore the role of photolysis in the environmental fate of hydroxychloroquine (HCQ) for the first time. The photolytic degradation of HCQ was investigated under simulated solar radiation (300-800 nm) in ultrapure, spring, river, and sea water. The effect of pH on the photodegradation rate was substantial and it was observed that degradation was faster at higher pH-values. Obtained half-lives ranged from 5.5 min at pH 9 to 23.1 h at pH 4. Humic acids, nitrate and iron(III) enhanced photodegradation of HCQ due to formation of hydroxyl radicals and its attack on HCQ molecule. In contrast, chloride, sulfate and bromide inhibited photodegradation. Additionally, the humic acids exhibited a dual role, photosensitization and inner filter effect. The study of the reaction kinetics was performed with HPLC-PDA, while the identification of degradation products formed during photolytic degradation was carried out using HPLC-MS/MS and NMR spectroscopy. The hydroxylation was recognized as the dominant path of photoproducts formation. The results of this research reveal the importance of photolytic degradation in environmental fate of HCQ and enable a better understanding of its behavior in the environment. Moreover, the results showing the significant effect of pH on the photodegradation of HCQ can be very useful in water treatment processes.
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Affiliation(s)
- Dario Dabić
- Department of Analytical Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev Trg 19, Zagreb, Croatia
| | - Sandra Babić
- Department of Analytical Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev Trg 19, Zagreb, Croatia.
| | - Irena Škorić
- Department of Organic Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev Trg 19, Zagreb, Croatia
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Photolysis of polychlorobiphenyls in the presence of nanocrystalline TiO2 and CdS/TiO2. REACTION KINETICS MECHANISMS AND CATALYSIS 2019. [DOI: 10.1007/s11144-019-01543-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Weber R, Gonser S, Köhler J, Körner W, Herold C, Haag R, Krapp M, Peichl L. Biomonitoring of polychlorinated biphenyls in Bavaria/Germany-long-term observations and standardization. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:16344-16354. [PMID: 29288297 DOI: 10.1007/s11356-017-1108-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 12/19/2017] [Indexed: 05/21/2023]
Abstract
In the 1980s, it was demonstrated that semi-volatile organic compounds (SVOCs) like polychlorinated biphenyls (PCBs) accumulate in plant leaves. Plants are at the base of the food chain, and therefore a starting point for transfer of PCBs to animals and related human exposure. For two decades, the Environment Agency of the German federal state of Bavaria (LfU) has been operating long-term monitoring stations to measure the impact of organic air pollutants. Standardized ryegrass, curly kale, and spruce needles are used as bioindicators for the atmospheric entries of PCBs into vegetation. From the end of 1990s to 2009, there was a marked decline in the concentrations of indicator PCBs (i-PCBs) and a minor decline in PCB-TEQ levels. After 2009, the concentrations leveled off. In rural areas, the median concentrations of Σ6 i-PCB in ryegrass and curly kale were about 3 and 4 μg/kg dm in 2000, and have been about 0.5 and 1 μg/kg dm since 2009, respectively. Concentrations in spruce needles fell from 0.9 to 0.4 μg/kg dm. Median PCB-TEQ concentrations in the bioindicator plants ranged from 0.05 to 0.23 ng/kg dm between 2002 and 2009 and from 0.15 to 0.05 ng/kg dm after 2009. Indicator PCB and PCB-TEQ concentrations were several times higher at the urban station in Munich than at the rural areas, reflecting the emissions from in-use PCB stocks in the building sector. The likely reason of the slower decrease of PCB-TEQ compared to i-PCBs is the formation of PCB-126 by dechlorination of industrial PCBs in open applications.
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Affiliation(s)
- Roland Weber
- POPs Environmental Consulting, D-73527, Schwäbisch Gmünd, Germany.
| | - Stefan Gonser
- Bavarian Environment Agency (LfU), Augsburg, Germany
| | - Jutta Köhler
- Bavarian Environment Agency (LfU), Augsburg, Germany
| | | | - Christine Herold
- POPs Environmental Consulting, D-73527, Schwäbisch Gmünd, Germany
| | | | - Margit Krapp
- Bavarian Environment Agency (LfU), Augsburg, Germany
| | - Ludwig Peichl
- Bavarian Environment Agency (LfU), Augsburg, Germany
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Tang T, Zheng Z, Wang R, Huang K, Li H, Tao X, Dang Z, Yin H, Lu G. Photodegradation behaviors of polychlorinated biphenyls in methanol by UV-irradiation: Solvent adducts and sigmatropic arrangement. CHEMOSPHERE 2018; 193:861-868. [PMID: 29874760 DOI: 10.1016/j.chemosphere.2017.11.095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 10/26/2017] [Accepted: 11/18/2017] [Indexed: 06/08/2023]
Abstract
This study has investigated the photolysis of polychlorinated biphenyls (PCBs) in methanol solution under UV irradiation. The results showed that the PCBs containing ortho-chlorine can generate both hydroxylated and methoxylated PCBs (HO-PCBs and MeO-PCBs), while the PCBs with a meta-chlorine but without ortho-chlorine can only generate MeO-PCBs as the only solvent adducts. No solvent adducts were detected during the photochemical reaction of 4-chlorobiphenyl (PCB-3), indicating the para-chlorine cannot be attacked by solvent molecule to form correspondent solvent adducts. The sigmatropic rearrangement was found during the photochemical reaction of ortho-substituted PCBs, but cannot occur in the reaction of PCBs with only meta- or para-chlorine, indicating that ortho-chlorine played a vital role in the sigmatropic rearrangement reaction. In addition, the seteric hindrance can also lead to the generation of sigmatropic rearrangement products. The effect of solvent was investigated in the case of photochemical reaction of 2-chlorobiphenyl (PCB-1), the results showed that sigmatropic rearrangement can occur in different solvents, and corresponding solvent adducts were generated in the photochemical reaction of PCB-1 in different solvents.
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Affiliation(s)
- Ting Tang
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Zhiqiang Zheng
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Rui Wang
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Kaibo Huang
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Huafeng Li
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Xueqin Tao
- School of Environmental Science and Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Zhi Dang
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, China
| | - Hua Yin
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, China
| | - Guining Lu
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; Guangdong Provincial Engineering and Technology Research Center for Environmental Risk Prevention and Emergency Disposal, Guangzhou 510006, China.
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Holt E, Kočan A, Klánová J, Assefa A, Wiberg K. Spatiotemporal patterns and potential sources of polychlorinated biphenyl (PCB) contamination in Scots pine (Pinus sylvestris) needles from Europe. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:19602-19612. [PMID: 27392626 DOI: 10.1007/s11356-016-7171-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 06/30/2016] [Indexed: 06/06/2023]
Abstract
Using pine needles as a bio-sampler of atmospheric contamination is a relatively cheap and easy method, particularly for remote sites. Therefore, pine needles have been used to monitor a range of semi-volatile contaminants in the air. In the present study, pine needles were used to monitor polychlorinated biphenyls (PCBs) in the air at sites with different land use types in Sweden (SW), Czech Republic (CZ), and Slovakia (SK). Spatiotemporal patterns in levels and congener profiles were investigated. Multivariate analysis was used to aid source identification. A comparison was also made between the profile of indicator PCBs (ind-PCBs-PCBs 28, 52, 101, 138, 153, and 180) in pine needles and those in active and passive air samplers. Concentrations in pine needles were 220-5100 ng kg(-1) (∑18PCBs - ind-PCBs and dioxin-like PCBs (dl-PCBs)) and 0.045-1.7 ng toxic equivalent (TEQ) kg(-1) (dry weight (dw)). Thermal sources (e.g., waste incineration) were identified as important sources of PCBs in pine needles. Comparison of profiles in pine needles to active and passive air samplers showed a lesser contribution of lower molecular weight PCBs 28 and 52, as well as a greater contribution of higher molecular weight PCBs (e.g., 180) in pine needles. The dissimilarities in congener profiles were attributed to faster degradation of lower chlorinated congeners from the leaf surface or metabolism by the plant.
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Affiliation(s)
- Eva Holt
- Research Centre for Toxic Compounds in the Environment (RECETOX), Masaryk University, Kamenice 753/5, 625 00, Brno, Czech Republic.
| | - Anton Kočan
- Research Centre for Toxic Compounds in the Environment (RECETOX), Masaryk University, Kamenice 753/5, 625 00, Brno, Czech Republic
| | - Jana Klánová
- Research Centre for Toxic Compounds in the Environment (RECETOX), Masaryk University, Kamenice 753/5, 625 00, Brno, Czech Republic
| | - Anteneh Assefa
- Department of Chemistry, Umea University, 901 87, Umeå, Sweden
| | - Karin Wiberg
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Box 7050, 750 07, Uppsala, Sweden
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14
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Sakai N, Dayana E, Abu Bakar A, Yoneda M, Nik Sulaiman NM, Ali Mohd M. Occurrence, distribution, and dechlorination of polychlorinated biphenyls and health risk assessment in Selangor River basin. ENVIRONMENTAL MONITORING AND ASSESSMENT 2016; 188:592. [PMID: 27679511 DOI: 10.1007/s10661-016-5595-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 09/14/2016] [Indexed: 06/06/2023]
Abstract
Polychlorinated biphenyls (PCBs) were monitored in surface water collected in the Selangor River basin, Malaysia, to identify the occurrence, distribution, and dechlorination process as well as to assess the potential adverse effects to the Malaysian population. Ten PCB homologs (i.e., mono-CBs to deca-CBs) were quantitated by using gas chromatography-mass spectrometry (GC/MS). The total concentration of PCBs in the 10 sampling sites ranged from limit of detection to 7.67 ng L-1. The higher chlorinated biphenyls (tetra-CBs to deca-CBs) were almost not detected in most of the sampling sites, whereas lower chlorinated biphenyls (mono-CBs, di-CBs, and tri-CBs) dominated more than 90 % of the 10 homologs in all the sampling sites. Therefore, the PCB load was estimated to be negligible during the sampling period because PCBs have an extremely long half-life. The PCBs, particularly higher chlorinated biphenyls, could be thoroughly dechlorinated to mono-CBs to tri-CBs by microbial decomposition in sediment or could still be accumulated in the sediment. The lower chlorinated biphenyls, however, could be resuspended or desorbed from the sediment because they have faster desorption rates and higher solubility, compared to the higher chlorinated biphenyls. The health risk for the Malaysia population by PCB intake that was estimated from the local fish consumption (7.2 ng kg-1 bw day-1) and tap water consumption (1.5 × 10-3-3.1 × 10-3 ng kg-1 bw day-1) based on the detected PCB levels in the surface water was considered to be minimal. The hazard quotient based on the tolerable daily intake (20 ng kg-1 bw day-1) was estimated at 0.36.
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Affiliation(s)
- Nobumitsu Sakai
- Division of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto, 6158540, Japan.
- Shimadzu-UMMC Centre of Xenobiotic Studies, Department of Pharmacology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Emmy Dayana
- Shimadzu-UMMC Centre of Xenobiotic Studies, Department of Pharmacology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Azizi Abu Bakar
- University of Malaya-Kyoto University Secretariat, Research Management and Innovation Complex (RMIC), University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Minoru Yoneda
- Division of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto, 6158540, Japan
| | - Nik Meriam Nik Sulaiman
- University of Malaya-Kyoto University Secretariat, Research Management and Innovation Complex (RMIC), University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Mustafa Ali Mohd
- Shimadzu-UMMC Centre of Xenobiotic Studies, Department of Pharmacology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
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15
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Nguyen M, Zahran EM, Wilbon AS, Besmer AV, Cendan VJ, Ranson WA, Lawrence RL, Cohn JL, Bachas LG, Knecht MR. Converting Light Energy to Chemical Energy: A New Catalytic Approach for Sustainable Environmental Remediation. ACS OMEGA 2016; 1:41-51. [PMID: 27656687 PMCID: PMC5026461 DOI: 10.1021/acsomega.6b00076] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 06/16/2016] [Indexed: 06/06/2023]
Abstract
We report a synthetic approach to form cubic Cu2O/Pd composite structures and demonstrate their use as photocatalytic materials for tandem catalysis. Pd nanoparticles were deposited onto Cu2O cubes, and their tandem catalytic reactivity was studied via the reductive dehalogenation of polychlorinated biphenyls. The Pd content of the materials was gradually increased to examine its influence on particle morphology and catalytic performance. Materials were prepared at different Pd amounts and demonstrated a range of tandem catalytic reactivity. H2 was generated via photocatalytic proton reduction initiated by Cu2O, followed by Pd-catalyzed dehalogenation using in situ generated H2. The results indicate that material morphology and composition and substrate steric effects play important roles in controlling the overall reaction rate. Additionally, analysis of the postreacted materials revealed that a small number of the cubes had become hollow during the photodechlorination reaction. Such findings offer important insights regarding photocatalytic active sites and mechanisms, providing a pathway toward converting light-based energy to chemical energy for sustainable catalytic reactions not typically driven via light.
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Affiliation(s)
- Michelle
A. Nguyen
- Department
of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Elsayed M. Zahran
- Department
of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Azaan S. Wilbon
- Department
of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Alexander V. Besmer
- Department
of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Vincent J. Cendan
- Department
of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - William A. Ranson
- Department
of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Randy L. Lawrence
- Department
of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Joshua L. Cohn
- Department
of Physics, University of Miami, 1320 Campo Sano Drive, Coral Gables, Florida 33146, United States
| | - Leonidas G. Bachas
- Department
of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
| | - Marc R. Knecht
- Department
of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146, United States
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16
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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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17
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Wang S, Hao C, Gao Z, Chen J, Qiu J. Theoretical investigation on photodechlorination mechanism of polychlorinated biphenyls. CHEMOSPHERE 2014; 95:200-205. [PMID: 24055025 DOI: 10.1016/j.chemosphere.2013.08.066] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 08/07/2013] [Accepted: 08/16/2013] [Indexed: 06/02/2023]
Abstract
Photodechlorination is a key process affecting the fate and effect of polychlorinated biphenyls (PCBs) in the environment. However, there are still numerous gaps in our knowledge, which become apparent in photodechlorination mechanism of PCBs. We investigated the conformations of 35 PCB congeners in the ground state and the first triplet excited state (T1), and predicted the photodechlorination pathway of the PCBs by calculating bond dissociation energies of the C-Cl bonds and activation energies of the C-Cl bond dissociation in the excited T1 state. Results show that the torsional degree of the two benzene rings of the PCBs depends on the number of ortho chlorines because of steric effect in the ground state. The two benzene rings of the PCBs with low photoreactivity tend to be coplanar and their torsional degree becomes lower in the excited T1 state compared with those in the ground state. The serious deformation and non-coplane of the benzene rings of some PCBs (e.g. PCB138) in the excited T1 state reduces the conjugation between the two benzene rings, implying that these PCBs have high photoreactivity. The dissociation of the C-Cl bond is the rate-determining step in the photodechlorination reactions of PCBs when the hydrogen donor is methanol. The main photodechlorination pathways predicted in this study are in good agreement with previous experimental results. Our results have provided new insights into mechanism of PCBs photodechlorination, which could be useful in the future in utilizing quantum chemistry calculation in investigating the environmental behavior and fate of organic pollutants.
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Affiliation(s)
- Se Wang
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
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18
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Wei H, Zou Y, Li A, Christensen ER, Rockne KJ. Photolytic debromination pathway of polybrominated diphenyl ethers in hexane by sunlight. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2013; 174:194-200. [PMID: 23274447 DOI: 10.1016/j.envpol.2012.11.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 10/19/2012] [Accepted: 11/29/2012] [Indexed: 06/01/2023]
Abstract
The objective of this work is to identify the photolytic debromination pathways of polybrominated diphenyl ethers (PBDEs). Thirteen PBDEs (BDEs 209, 208, 207, 206, 196, 183, 154, 153, 100, 99, 85, 47 and 28) in hexane were individually exposed to sunlight for up to 64 h. A total of 180 PBDEs were screened and 74 BDE debromination products were detected. The disappearance rate constant increased exponentially with increasing number of bromines. While no evident difference in debromination preference among ortho, meta and para bromines was found for heavier congeners, the vulnerability rank order was meta ≥ ortho > para for the lighter congeners (≤8 Br). The total molar mass of PBDEs continuously decreased during sunlight exposure, indicating PBDEs were transformed to non-PBDE compounds. A stochastic least squares debromination pathway model was developed to simulate the reactions and determine the yields to extend the results beyond the experimental observations.
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Affiliation(s)
- Hua Wei
- School of Public Health, University of Illinois at Chicago, 2121 West Taylor Street, Chicago, IL 60612, USA
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19
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Yu L, Izadifard M, Achari G, Langford CH. Electron transfer sensitized photodechlorination of surfactant solubilized PCB 138. CHEMOSPHERE 2013; 90:2347-2351. [PMID: 23141843 DOI: 10.1016/j.chemosphere.2012.10.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 09/18/2012] [Accepted: 10/17/2012] [Indexed: 06/01/2023]
Abstract
Sensitized photodechlorination of polychlorinated biphenyl, PCB 138, in three different surfactant solutions was studied. The sensitizer of choice was leuco-methylene blue, which was produced in situ from methylene blue using either triethylamine or sodium borohydride. Three types of surfactants, anionic (SDS), neutral (TWEEN 80), and cationic (CTAB) at different concentrations were investigated. The neutral and cationic surfactants were found to be more effective than anionic. In each case the surfactant concentration was found to play a significant role in the rate of dechlorination. For different sensitized systems (triethylamine or sodium borohydride), a different product distribution and a different pathway of dechlorination was observed.
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Affiliation(s)
- Linlong Yu
- Department of Civil Engineering, University of Calgary, Calgary, Alberta, Canada
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20
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Sanchez-Prado L, Kalafata K, Risticevic S, Pawliszyn J, Lores M, Llompart M, Kalogerakis N, Psillakis E. Ice photolysis of 2,2′,4,4′,6-pentabromodiphenyl ether (BDE-100): Laboratory investigations using solid phase microextraction. Anal Chim Acta 2012; 742:90-6. [DOI: 10.1016/j.aca.2012.06.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 06/06/2012] [Accepted: 06/07/2012] [Indexed: 10/28/2022]
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21
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Dasary SSR, Saloni J, Fletcher A, Anjaneyulu Y, Yu H. Photodegradation of selected PCBs in the presence of Nano-TiO2 as catalyst and H2O2 as an oxidant. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2010; 7:3987-4001. [PMID: 21139872 PMCID: PMC2996220 DOI: 10.3390/ijerph7113987] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 10/25/2010] [Accepted: 11/12/2010] [Indexed: 01/11/2023]
Abstract
Photodegradation of five strategically selected PCBs was carried out in acetonitrile/water 80:20. Quantum chemical calculations reveal that PCBs without any chlorine on ortho-positions are closer to be planar, while PCBs with at least one chlorine atoms at the ortho-positions causes the two benzene rings to be nearly perpendicular. Light-induced degradation of planar PCBs is much slower than the perpendicular ones. The use of nano-TiO2 speeds up the degradation of the planar PCBs, but slows down the degradation of the non-planar ones. The use of H2O2 speeds up the degradation of planar PCBs greatly (by >20 times), but has little effect on non-planar ones except 2,3,5,6-TCB. The relative photodegradation rate is: 2,2′,4,4′-TCB > 2,3,5,6-TCB > 2,6-DCB ≈ 3,3′,4,4′-TCB > 3,4′,5-TCB. The use of H2O2 in combination with sunlight irradiation could be an efficient and “green” technology for PCB remediation.
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Affiliation(s)
- Samuel S R Dasary
- Department of Chemistry and Biochemistry, Jackson State University, 1400 J. R. Lynch Street, P.O. Box 17910, Jackson, MS 39217, USA.
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22
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Li X, Huang J, Yu G, Deng S. Photodestruction of BDE-99 in micellar solutions of nonionic surfactants of Brij 35 and Brij 58. CHEMOSPHERE 2010; 78:752-759. [PMID: 20006893 DOI: 10.1016/j.chemosphere.2009.10.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 10/09/2009] [Accepted: 10/10/2009] [Indexed: 05/28/2023]
Abstract
Currently, soil contamination by polybrominated diphenyl ethers (PBDEs) at e-waste recycling sites in China is of significant environmental concern and requires the identification of appropriate remediation technologies. In this paper, photodestruction of a model PBDE congener (BDE-99) in selected UV/surfactant systems was investigated, using a RPR-200 Rayonet photochemical reactor equipped with two low-pressure mercury lamps. BDE-99 photodegradation in the micellar solutions of nonionic surfactants of Brij 35 and Brij 58 all followed pseudo first-order kinetics and the photodegradation quantum yields were 1.8-2.4 times as high as that in water alone. The photodegradation was comparably enhanced by Brij 35 and Brij 58, and the quenching effect of dissolved oxygen (DO) was eliminated in their presence. Mono- to tetra-BDEs were identified as one group of BDE-99 photoproducts, indicating that one of BDE-99 photodegradation pathways was through a sequential loss of Br. The pattern of PBDE photoproducts showed the photodebromination of BDE-99 readily occurred on the more heavily substituted phenyl ring. Mono- to tetra-polybrominated dibenzofurans (PBDFs) were identified as another group of photoproducts, indicating BDE-99 can also photodegrade through a dibenzofuran-type ring closure process via an intramolecular elimination of HBr. In addition, the formation of these more toxic photoproducts (PBDFs) was not related to the presence of DO. Finally, the later disappearance of mono-BDEs and mono-BDFs suggested the UV exposure time would be an important technical parameter if the technology of UV photodestruction of PBDEs in surfactant micellar solutions is applied to PBDE-contaminated soil remediation.
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Affiliation(s)
- Xue Li
- POPs Research Center, Tsinghua University, Beijing 100084, PR China
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23
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Wang K, Guo J, Yang M, Junji H, Deng R. Decomposition of two haloacetic acids in water using UV radiation, ozone and advanced oxidation processes. JOURNAL OF HAZARDOUS MATERIALS 2009; 162:1243-1248. [PMID: 18692959 DOI: 10.1016/j.jhazmat.2008.06.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 04/23/2008] [Accepted: 06/09/2008] [Indexed: 05/26/2023]
Abstract
The decomposition of two haloacetic acids (HAAs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), from water was studied by means of single oxidants: ozone, UV radiation; and by the advanced oxidation processes (AOPs) constituted by combinations of O(3)/UV radiation, H(2)O(2)/UV radiation, O(3)/H(2)O(2), O(3)/H(2)O(2)/UV radiation. The concentrations of HAAs were analyzed at specified time intervals to elucidate the decomposition of HAAs. Single O(3) or UV did not result in perceptible decomposition of HAAs within the applied reaction time. O(3)/UV showed to be more suitable for the decomposition of DCAA and TCAA in water among the six methods of oxidation. Decomposition of DCAA was easier than TCAA by AOPs. For O(3)/UV in the semi-continuous mode, the effective utilization rate of ozone for HAA decomposition decreased with ozone addition. The kinetics of HAAs decomposition by O(3)/UV and the influence of coexistent humic acids and HCO(3)(-) on the decomposition process were investigated. The decomposition of the HAAs by the O(3)/UV accorded with the pseudo-first-order mode under the constant initial dissolved O(3) concentration and fixed UV radiation. The pseudo-first-order rate constant for the decomposition of DCAA was more than four times that for TCAA. Humic acids can cause the H(2)O(2) accumulation and the decrease in rate constants of HAAs decomposition in the O(3)/UV process. The rate constants for the decomposition of DCAA and TCAA decreased by 41.1% and 23.8%, respectively, when humic acids were added at a concentration of 1.2mgTOC/L. The rate constants decreased by 43.5% and 25.9%, respectively, at an HCO(3)(-) concentration of 1.0mmol/L.
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Affiliation(s)
- Kunping Wang
- Chinese Education Ministry Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Chongqing University, Chongqing 400045, PR China.
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24
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Izadifard M, Achari G, Langford CH. The pathway of dechlorination of PCB congener by a photochemical chain process in 2-propanol: the role of medium and quenching. CHEMOSPHERE 2008; 73:1328-1334. [PMID: 18721997 DOI: 10.1016/j.chemosphere.2008.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 07/01/2008] [Accepted: 07/02/2008] [Indexed: 05/26/2023]
Abstract
As part of a program aimed at developing a field process for cleanup of PCB contaminated soils using photochemistry in basic 2-propanol, additional details of the dechlorination pathway are presented. The mechanism involves a chain reaction with both homolytic photochemical C-Cl bond fission and electron transfer steps producing PCB anion radicals. Kinetics of dechlorination of various congeners show patterns of relative rates associated with the basic 2-propanol medium that are not found in other media because both electron transfer and photochemical homolysis steps determine overall rates of dechlorination and govern the pathways and relative concentrations of intermediates. The electron transfer steps display opposite structure-reactivity correlations to the photo-homolysis, C-Cl bond fission steps. Oxygen quenching is shown to differentially affect both types of steps. In contrast to the suggestion that inter system crossing can be highly efficient with reaction originating from a PCB triplet, oxygen quenching data suggest that a significant minimum of the quantum yield is non-quenchable, presumably because of a reaction path from the PCB singlet. This may help to explain why exclusion of air is not entirely necessary in practice.
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Affiliation(s)
- Maryam Izadifard
- Department of Chemistry, University of Calgary, 2500 University Dr. NW Calgary, AB, Canada T2N 1N4
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25
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Ibuki Y, Tani Y, Toyooka T. UVB-Exposed Chlorinated Bisphenol A Generates Phosphorylated Histone H2AX in Human Skin Cells. Chem Res Toxicol 2008; 21:1770-6. [DOI: 10.1021/tx800129n] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yuko Ibuki
- Laboratory of Radiation Biology and Laboratory of Environmental Microbiology, Graduate School of Nutritional and Environmental Sciences, Institute for Environmental Sciences, University of Shizuoka, 52-1 Yada, Shizuoka-shi 422-8526, Japan
| | - Yukinori Tani
- Laboratory of Radiation Biology and Laboratory of Environmental Microbiology, Graduate School of Nutritional and Environmental Sciences, Institute for Environmental Sciences, University of Shizuoka, 52-1 Yada, Shizuoka-shi 422-8526, Japan
| | - Tatsushi Toyooka
- Laboratory of Radiation Biology and Laboratory of Environmental Microbiology, Graduate School of Nutritional and Environmental Sciences, Institute for Environmental Sciences, University of Shizuoka, 52-1 Yada, Shizuoka-shi 422-8526, Japan
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26
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Mutou Y, Ibuki Y, Terao Y, Kojima S, Goto R. Induction of apoptosis by UV-irradiated chlorinated bisphenol A in Jurkat cells. Toxicol In Vitro 2008; 22:864-72. [PMID: 18280695 DOI: 10.1016/j.tiv.2008.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 12/18/2007] [Accepted: 01/03/2008] [Indexed: 10/22/2022]
Abstract
Chlorinated derivatives of bisphenol A (ClBPAs) have been detected in wastewater from waste paper recycling plants. We previously reported that bisphenol A (BPA) and ClBPAs [3-chlorobisphenol A, 3,3'-dichlorobisphenol A, and 3,3',5-trichlorobisphenol A] irradiated with ultraviolet (UV) B or UVC (not with UVA) induced inhibition of cell growth, and that 3-hydroxybisphenol A (3-OHBPA) was detected in the photoproducts [Mutou, Y., Ibuki, Y., Terao, Y., Kojima, S., Goto, R., 2006b. Chemical change of chlorinated bisphenol A by ultraviolet irradiation and cytotoxicity of their products on Jurkat cells. Environmental Toxicology and Pharmacology, 21, 283-289]. The formation of hydroxylated BPAs by UV irradiation might contribute to the inhibition of cell growth, but the mechanism of the growth inhibition is not clarified. In this study, we investigated whether BPA and ClBPAs exposed to UVA, UVB, or UVC, and 3-OHBPA could induce the death of Jurkat cells and whether the pattern of cell death was apoptosis. ClBPAs exposed to UVB and UVC induced significant cell death, but those exposed to UVA and BPA did not. The cell death was apoptosis because chromatin condensation and DNA fragmentation were detected. Activation of caspase-3, -8, and -9 and cytochrome c release indicated that ClBPAs exposed to UVB or UVC induced apoptosis via typical apoptotic pathways. In addition, 3-OHBPA induced apoptosis similar to UVB- or UVC-irradiated ClBPA. These results suggested that the photoproducts of ClBPAs generated by UV irradiation, containing 3-OHBPA, contributed to the induction of apoptosis.
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Affiliation(s)
- Yasuko Mutou
- Laboratory of Radiation Biology, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Shizuoka-shi 422-8526, Japan
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Li X, Fang L, Huang J, Yu G. Photolysis of mono- through deca-chlorinated biphenyls by ultraviolet irradiation in n-hexane and quantitative structure-property relationship analysis. J Environ Sci (China) 2008; 20:753-759. [PMID: 18763572 DOI: 10.1016/s1001-0742(08)62123-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The photolysis of 16 polychlorinated biphenyls (PCBs) (including mono- through deca-chlorinated) in n-hexane was investigated under ultraviolet irradiation using a 500-W high-pressure mercury lamp. Photolysis of PCBs follows pseudo-first-order reaction kinetics, with photolysis rate constants ranging between 0.0011 s(-1) for PCB-52 and 0.0574 s(-1) for PCB-118. The degradation rates of PCBs by high-pressure mercury lamp irradiation were remarkably independent with respect to the degree of chlorination. Furthermore, partial least squares (PLS) models were developed to provide insight into which aspect of the molecular structure influenced PCB photolysis rate constants. It was found that the photolysis rates of PCBs increased with an increase in the net charge on the carbon atom (qc), (E(LUMO)-E(HOMO))2, and the Y-axis dipole moment (mu(y)) values, or the decrease in the energy of the second highest occupied molecular orbital (E(HOMO-1)), energy of the lowest unoccupied molecular orbital (E(LUMO)), E(LUMO) + E(HOMO), E(LUMO)--E(HOMO), most positive atomic charge (q+), and the twist angle of the chlorine atom (TA) values.
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Affiliation(s)
- Xue Li
- POPs Research Centre, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China.
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28
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Sánchez-Prado L, Lores M, Llompart M, García-Jares C, Bayona JM, Cela R. Natural sunlight and sun simulator photolysis studies of tetra- to hexa-brominated diphenyl ethers in water using solid-phase microextraction. J Chromatogr A 2006; 1124:157-66. [PMID: 16824536 DOI: 10.1016/j.chroma.2006.06.037] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Revised: 06/09/2006] [Accepted: 06/12/2006] [Indexed: 11/25/2022]
Abstract
Photo-solid-phase microextraction (photo-SPME) is combined for the first time with natural and simulated sunlight to study the photochemical behaviour of environmental concerning tetra- to hexa-brominated diphenyl ethers. The sunlight photodegradation kinetics of five brominated diphenyl ethers (BDE 47, BDE 100, BDE 99, BDE 154 and BDE 153) has been studied. These BDEs are the most abundant congeners in penta-BDE commercial formulations used as flame-retardants and are considered among the most toxic ones. The five studied BDEs were photolytically labile. The detected photodegradation products include more stable lower brominated diphenyl ethers and polybrominated dibenzofurans (PBDFs). The photoformation and decay kinetics of these photoproducts were also monitorized by photo-SPME. Aqueous photodegradation studies have also been carried out. In this case, SPME is only used as the extraction technique. Obtained results in the aqueous photodegradation experiments were compared with those obtained in photo-SPME experiments.
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Affiliation(s)
- Lucía Sánchez-Prado
- Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Química, Instituto de Investigación y Análisis Alimentario, Universidad de Santiago de Compostela, Avda. das Ciencias s/n, 15782 Santiago de Compostela, Spain
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29
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Mutou Y, Ibuki Y, Terao Y, Kojima S, Goto R. Chemical change of chlorinated bisphenol A by ultraviolet irradiation and cytotoxicity of their products on Jurkat cells. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2006; 21:283-9. [PMID: 21783670 DOI: 10.1016/j.etap.2005.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Accepted: 09/28/2005] [Indexed: 05/17/2023]
Abstract
Chlorinated derivatives of bisphenol A (ClBPAs) have been detected in wastewater from waste paper recycling plants. BPA and ClBPAs are always exposed to ultraviolet (UV) radiation in the environment and consequently various photoproducts might be produced. Acute cytotoxicity of photoproducts of BPA and ClBPAs are not known. In this study, we investigated the cytotoxicity and chemical structure of photoproducts of BPA and ClBPAs (3-chlorobisphenol A (3-ClBPA), 3,3'-dichlorobisphenol A (3,3'-diClBPA) and 3,3',5-trichlorobisphenol A (3,3',5-triClBPA)) after UV irradiation (UVA, UVB and UVC). The toxicities of photoproducts on Jurkat cells were determined by Alamar Blue assay, and the chemical structures of the photoproducts were identified using GC/MS. The cytotoxicities of 3-ClBPA and 3,3'-diClBPA were higher than that of BPA and 3,3',5-triClBPA. In addition, the toxicities of ClBPAs were increased by the irradiation of UVB and UVC at 100J/cm(2) and decreased at 1000J/cm(2) in comparison with those at 100J/cm(2), indicating that their structures had changed. 3-Hydroxybisphenol A (3-OHBPA) was detected in the photoproducts of 3-ClBPA irradiated with UVB and UVC at 100J/cm(2), and 3-OHBPA and 3-chloro-3'-hydroxybisphenol A (3-Cl-3'-OHBPA) were detected in those of 3,3'-diClBPA. However, these hydroxylated BPAs were not detected in the photoproducts exposed to 1000J/cm(2). The cytotoxicity of 3-OHBPA was the almost same as ClBPAs after UVB and UVC irradiation. These results indicate that the formation of hydroxylated BPAs might contribute to the increase in toxicity caused by UV irradiation.
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Affiliation(s)
- Yasuko Mutou
- Laboratory of Radiation Biology, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Shizuoka-shi 422-8526, Japan
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Niu JF, Yang ZF, Shen ZY, Wang LL. QSPRs for the prediction of photodegradation half-life of PCBs in n-hexane. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2006; 17:173-82. [PMID: 16644556 DOI: 10.1080/10659360600636170] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
By partial least squares (PLS) regression analysis, a quantitative structure-property relationship (QSPR) model was developed for photodegradation half-life (t1/2) of polychlorinated biphenyls (PCBs) in n-hexane solution under UV irradiation. Quantum chemical descriptors computed by PM3 Hamiltonian were used as predictor variables. The cross-validated value for the optimal QSPR model was 0.589, indicating good predictive capability for log t1/2 values of PCBs in n-hexane. The QSPR results show that standard heat of formation (DeltaHf), total energy (TE), and molecular weight (Mw) have dominant effect on t1/2 values of PCBs in n-hexane. Increasing DeltaHf and TE values or decreasing Mw values of the PCBs leads to decrease of log t1/2 values. In addition, increasing the largest negative atomic charge on a carbon atom and dipole moment of the PCBs leads to decrease of log t1/2 values.
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Affiliation(s)
- J F Niu
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, P. R. China.
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Sanchez-Prado L, Llompart M, Lores M, Garcia-Jares C, Cela R. Investigation of photodegradation products generated after UV-irradiation of five polybrominated diphenyl ethers using photo solid-phase microextraction. J Chromatogr A 2005; 1071:85-92. [PMID: 15865178 DOI: 10.1016/j.chroma.2004.10.065] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In this study, the photoinduced degradation of five polybrominated diphenyl ethers (PBDEs), BDE-47, BDE-100, BDE-99, BDE-154 and BDE-153, is studied using solid-phase microextraction polydimethylsiloxane fibers as photolytic support. PBDEs are extracted from aqueous solutions using SPME fibers that are subsequently exposed to UV irradiation for different times (from 2 to 60 min). Photodegradation kinetics of the five PBDEs, tentative identification and photochemical behavior of the generated photoproducts, as well as photodegradation pathways, have been studied employing this on-fiber approach technique (photo-SPME) followed by gas chromatography-mass spectrometry analysis. Aqueous photodegradation studies have also been performed and compared with photo-SPME. All the photoproducts detected in the aqueous experiments were previously found in the photo-SPME experiments. In this study, reductive debromination by successive losses of bromine atoms is confirmed as the main photodegradation pathway of PBDEs. A large number of PBDEs were obtained as photoproducts of the five target analytes. Other mechanism of photodegradation observed was intramolecular cyclization from the homolytic dissociation of the C-Br bond; thus, polybromo-dibenzofurans were generated. This work contributes to the study of the photodegradation of PBDEs and shows the potential of photo-SPME to evaluate the photo-transformation of organic pollutants.
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Affiliation(s)
- Lucia Sanchez-Prado
- Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Química, Instituto de Investigación y Análisis Alimentario, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
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