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Wang X, Han Y, Hadizadeh MH, Wang W, Zhang Q, Hu Y, Xu F, Sun Y, Wang W. Periodic DFT calculations for the heterogeneous formation of 2-chlorothiophenoxy radical from 2-chlorothiophenol on Cu(111) surface in fly ash. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 274:116186. [PMID: 38471341 DOI: 10.1016/j.ecoenv.2024.116186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 02/26/2024] [Accepted: 03/05/2024] [Indexed: 03/14/2024]
Abstract
Copper plays a crucial role in the heterogenous dissociation of chlorothiophenols (CTPs) to form chlorothiophenoxy radicals (CTPRs), which is the initial and critical step in the formation of polychlorinated thianthrenes/dibenzothiophenes (PCTA/DTs). Here, first-principles calculations were performed to investigate the activity of Cu(111) surface towards the formation of adsorbed 2-CTPR from 2-CTP. The interaction between 2-CTP and Cu(111) surface was explored to find stable adsorption configurations. Besides, the decomposition routes of 2-CTP on the Cu(111) surface were further explored. Moreover, the effects of water on the formation of absorbed 2-CTPR on the Cu(111) surface were examined. Our results demonstrate that the flat adsorption of 2-CTP on the surface with adsorption energy in the range of -33.21 kcal/mol to -28.37 kcal/mol is more stable than the vertical adsorption with adsorption energy ranging from -23.53 kcal/mol to -13.38 kcal/mol. The Cu(111) surface catalyzes the conversion of 2-CTP into the adsorbed 2-CTPR with a modest energy barrier of 9.46 kcal/mol. Furthermore, water molecules exhibit stronger catalytic activity in this process with a decreased energy barrier of 5.87 kcal/mol through "water bridge" and hydrogen bonding. Specifically, the water accepts the hydrogen atom from 2-CTP and donates another hydrogen to the surface via "water bridge". This research provides a molecular-level understanding of the heterogeneous formation of PCTA/DTs by fly ash, suggesting novel approaches for control strategy and legislation of dioxin analogues.
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Affiliation(s)
- Xiaotong Wang
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Yanan Han
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | | | - Wei Wang
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Qi Zhang
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Yongxia Hu
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Fei Xu
- Environment Research Institute, Shandong University, Qingdao 266237, China; Shenzhen Research Institute of Shandong University, Shenzhen 518057, China.
| | - Yanhui Sun
- College of Environment and Safety Engineering, Qingdao University of Science & Technology, Qingdao 266042, China
| | - Wenxing Wang
- Environment Research Institute, Shandong University, Qingdao 266237, China
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Assessment of PCDD/Fs Emission during Industrial-Organic-Solid-Waste Incineration Process in a Fluidized-Bed Incinerator. Processes (Basel) 2023. [DOI: 10.3390/pr11010251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
This study was conducted in a fluidized-bed incineration plant, evaluating the formation, emission and flux of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from industrial-organic-solid-waste (IW) incineration. The results revealed that both the total (or I-TEQ) concentrations of toxic and 136 total PCDD/Fs in flue gas (FG), fly ash (FA) and bottom ash (BA)were ramped up to a higher level than those during municipal-solid-waste (MSW) incineration. A possible explanation was the chlorine (Cl) content of IW. However, the emitted PCDD/Fs in FG (FA/BA) still fulfilled the criteria. Subsequently, similar distribution patterns of PCDD/F isomers were observed in subsystems, indicating a unified formation-pathway. De novo synthesis was detected as the dominant formation-pathway of PCDD/Fs, while high-temperature and precursor syntheses were excluded. DD/DF chlorination formed PCDD/Fs to some extent. Furthermore, the mass flow chart indicated that PCDD/Fs output in primary FG was significantly strengthened (>1000 times) by de novo synthesis, from 1.25 μg I-TEQ/h to 1.67 mg I-TEQ/h. With effective cleaning by APCS, 99.6% of PCDD/Fs in FG were purified. PCDD/Fs in the gas phase were finally emitted at a discharge rate of 7.25 μg I-TEQ/h. However, accumulated FA took most PCDD/Fs into the environment (>99%), reaching 3.56 mg I-TEQ/h.
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Effect of Water Molecule on the Complete Series Reactions of Chlorothiobenzenes with H/·OH: A Theoretical Study. ATMOSPHERE 2022. [DOI: 10.3390/atmos13050849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The chlorothiobenzenes (CTBs) are the principal precursors for the formation of polychlorinated thianthrene/dibenzothiophenes (PCTA/DTs), which have high toxicity and wide distribution in the environment. Under the pyrolysis or combustion conditions, CTBs can react with H/·OH radicals to form the chlorothiobenzyl radicals (CTBRs) through abstraction of the chlorothiobenzyl-hydrogen. The water molecule can play an important role in this process. The coupling of CTBRs is the essential first step in forming PCTA/DTs. In this paper, quantum chemical calculations were carried out to investigate the formation of CTBRs from the complete series reactions of 19 chlorothiobenzene (CTB) congeners with H/·OH radicals in the presence of the water molecule. Using the MPWB1K/6-311 + G(3df,2p)//MPWB1K/6-31 + G(d,p) energy level, schematic energy profiles were constructed with the water molecule and then compared with the non-hydrated case. The present study shows that structural parameters and thermal data, as well as CTBRs formation potential from CTBs, are strongly dominated by the chlorine substitution at the ortho-position of CTBs. Meanwhile, the water molecule can promote the CTBR formation from CTBs abstracted by H/·OH, which has a stronger catalysis effect on the H abstraction from CTBs by OH than from CTBs by H. This study may provide reference parameters for future experimental research, which would enhance measures to reduce dioxin emission and establish dioxin control strategies.
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Shi X, Huang G, Yang D, Zhang Q, Zong W, Cheng J, Sui X, Yuan F, Wang W. Theoretical study of the formation and nucleation mechanism of highly oxygenated multi-functional organic compounds produced by α-pinene. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 780:146422. [PMID: 33770596 DOI: 10.1016/j.scitotenv.2021.146422] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 03/02/2021] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Abstract
In recent years, highly oxygenated organic molecules (HOMs) derived from photochemical reactions of α-pinene, the most abundant monoterpene, have been considered as important precursors of biogenic particles. However, the specific reactions of HOMs remain largely unknown, especially the corresponding formation and nucleation mechanism in the nanoscale. In this study, we implemented quantum chemical calculations and molecular dynamics (MD) simulations to explore the mechanism of the formation of HOM monomers/dimers by ozonolysis and autoxidation of α-pinene. Furthermore, we investigated the mechanisms of HOMs with different oxygen-to‑carbon (O/C) ratios and functional groups participating in neutral and ion-induced nucleation. The results show that the formation of HOMs is hardly affected by water, sulfuric acid and ions. In the ion-induced nucleation, HOM can dominate the initial nucleation steps; however, in the neutral nucleation, HOMs are more likely to participate in the growth stage. In addition, the nucleation ability of HOM has a bearing on the O/C ratio and the types of the functional groups. The current calculations provide valuable insight into the formation mechanism of the pure organic particles at low sulfuric acid concentrations.
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Affiliation(s)
- Xiangli Shi
- College of Geography and Environment, Shandong Normal University, Jinan 250014, PR China
| | - Guoxuanzi Huang
- College of Geography and Environment, Shandong Normal University, Jinan 250014, PR China
| | - Dehui Yang
- College of Geography and Environment, Shandong Normal University, Jinan 250014, PR China
| | - Qingzhu Zhang
- Environment Research Institute, Shandong University, Jinan 250100, PR China
| | - Wansong Zong
- College of Geography and Environment, Shandong Normal University, Jinan 250014, PR China
| | - Jiemin Cheng
- College of Geography and Environment, Shandong Normal University, Jinan 250014, PR China.
| | - Xiao Sui
- College of Geography and Environment, Shandong Normal University, Jinan 250014, PR China
| | - Fanghui Yuan
- Rizhao Municipal Government Affairs Service Center, Rizhao 276800, PR China
| | - Wenxing Wang
- Environment Research Institute, Shandong University, Jinan 250100, PR China
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Li Y, Han Y, Teng Z, Zhao X, Sun Y, Xu F, Zhang Q, Wang W. The homogeneous gas-phase formation mechanisms of PCPTs/PCDTs/PCDFs from the radical/radical cross-condensation of 2-CPR and 2-CTPR: a theoretical, mechanistic and kinetics study. RSC Adv 2021; 11:12626-12640. [PMID: 35423822 PMCID: PMC8697067 DOI: 10.1039/d1ra00599e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/18/2021] [Indexed: 11/28/2022] Open
Abstract
Polychlorinated phenoxathiins (PCPTs) are one group of dioxin-like compounds, which can be considered to be one-oxygen-substituted polychlorinated thianthrene (PCTA) compounds or one-sulfur-substituted polychlorinated dibenzo-p-dioxin (PCDD) compounds. Owing to their high toxicity and wide distribution, clarifying the formation and emission of PCPTs due to combustion and thermal processes can deepen our understanding of the dioxin formation mechanism and allow reduced-emission and dioxin-control strategies to be established. Chlorophenols (CPs) and chlorothiophenols (CTPs) are direct precursors in PCPT formation. In this paper, the homogeneous gas-phase formation mechanisms of PCPTs, as well as polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzothiophenes (PCDTs), from the cross-condensation of 2-chlorophenoxy radicals (2-CPRs) and 2-chlorothiophenoxy radicals (2-CTPRs) under thermal and combustion conditions were investigated theoretically using a density functional theory (DFT) method. The reaction priorities and effects of water molecules on the formation mechanisms were discussed. The rate constants of crucial elementary steps were calculated from 600-1200 K. The acute and chronic toxicities of the main products were predicted at three trophic levels. This study shows that routes starting with oxygen-carbon condensation are favored over those starting with sulfur-carbon condensation for PCPT formation, and routes ending with Cl loss can occur more easily than those ending with H loss. Water molecules have a negative catalytic effect on CH-S H-transfer steps but a positive catalytic effect on CH-O H-transfer steps.
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Affiliation(s)
- Ying Li
- Environment Research Institute, Shandong University Qingdao 266237 P. R. China +86-532-58631992
| | - Yanan Han
- Environment Research Institute, Shandong University Qingdao 266237 P. R. China +86-532-58631992
| | - Zhuochao Teng
- Environment Research Institute, Shandong University Qingdao 266237 P. R. China +86-532-58631992
| | - Xianwei Zhao
- Environment Research Institute, Shandong University Qingdao 266237 P. R. China +86-532-58631992
| | - Yanhui Sun
- College of Environment and Safety Engineering, Qingdao University of Science & Technology Qingdao 266042 P. R. China
| | - Fei Xu
- Environment Research Institute, Shandong University Qingdao 266237 P. R. China +86-532-58631992
| | - Qingzhu Zhang
- Environment Research Institute, Shandong University Qingdao 266237 P. R. China +86-532-58631992
| | - Wenxing Wang
- Environment Research Institute, Shandong University Qingdao 266237 P. R. China +86-532-58631992
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6
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Bai FY, Ni S, Ren Y, Tang YZ, Zhao Z, Pan XM. DFT analysis on the removal of dimethylbenzoquinones in atmosphere and water environments: ·OH-initiated oxidation and captured by (TiO 2) n clusters (n=1-6). JOURNAL OF HAZARDOUS MATERIALS 2020; 386:121636. [PMID: 31753671 DOI: 10.1016/j.jhazmat.2019.121636] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 11/02/2019] [Accepted: 11/07/2019] [Indexed: 06/10/2023]
Abstract
The elimination mechanisms and the dynamics of 2,5-dimethylbenzoquinone/2,6-dimethylbenzoquinone are performed by DFT under the presence of ·OH radical and TiO2-clusters. The rate coefficients, calculated within the atmospheric and combustion temperature range of 200-2000 K, agree well with the experimental data. The subsequent reactions including the bond cleavage of quinone ring, O2 addition or abstraction, the reactions of peroxy radical with NO yielding the precursor of organic aerosol are studied. Gaseous water molecule plays an important role in the transformation of alkoxy radical and exhibits a catalytic performance in the enol-ketone tautomerism. The lifetimes of 2,5-dimethylbenzoquinone/2,6-dimethylbenzoquinone are about 12.04-12.86 h at 298 K, which are in favor of the medium range transport of them in the atmosphere. Significantly, the water environment plays a negative role on the ·OH-degradation of dimethylbenzoquinone. Compared to the quinone ring, 2,5-dimethylbenzoquinone onto (TiO2)n clusters (n = 1-6) is easier to be absorbed by TiO2-clusters through its oxygen site because of its strong chemisorption, which indicates that TiO2-clusters are capable of trapping dimethylbenzoquinones effectively. The water environment could weaken the adsorption of 2,5-dimethylbenzoquinone onto (TiO2)n clusters (n = 1-6) by increasing the adsorption energy. This work reveals the removal of dimethylbenzoquinones and the formation of organic aerosol under polluted environments.
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Affiliation(s)
- Feng-Yang Bai
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, 110034, People's Republic of China.
| | - Shuang Ni
- National & Local United Engineering Lab for Power Battery, Faculty of Chemistry, Northeast Normal University, Changchun, 130024, People's Republic of China
| | - Yu Ren
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Chang Ping, Beijing 102249, People's Republic of China
| | - Yi-Zhen Tang
- School of Environmental and Municipal Engineering, Qingdao Technological University, Qingdao 266033, People's Republic of China
| | - Zhen Zhao
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, 110034, People's Republic of China; State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Chang Ping, Beijing 102249, People's Republic of China
| | - Xiu-Mei Pan
- National & Local United Engineering Lab for Power Battery, Faculty of Chemistry, Northeast Normal University, Changchun, 130024, People's Republic of China.
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Wang Y, Liu C, Peng A, Gu C. Fomration of hydroxylated polychlorinated diphenyl ethers mediated by Structural Fe(III) in smectites. CHEMOSPHERE 2019; 226:94-102. [PMID: 30921641 DOI: 10.1016/j.chemosphere.2019.03.082] [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: 11/05/2018] [Revised: 02/28/2019] [Accepted: 03/12/2019] [Indexed: 06/09/2023]
Abstract
Fe(III)-bearing clay minerals are ubiquitous in the environment. However, the fate of organic contaminants mediated by structural Fe(III) in clays was rarely reported. Here we demonstrated that hydroxylated polychlorinated diphenyl ethers (HO-PCDEs) could be spontaneously formed from the reaction of 2,4,6-trichlorophenol (2,4,6-TCP) with three native smectites: SWy-2, NAu-1, and NAu-2. Further research demonstrated that the structural Fe(III) in smectite is indispensable for the mediation of 2,4,6-TCP to produce chlorophenoxy radical for the subsequent dimerization. The reaction is highly dependent on the relative humidity of the system and the site occupancy of structural Fe(III). Active structural Fe(III) in NAu-2 that played a significant role in the dimerization reaction is relatively more distorted, which would interact strongly with 2,4,6-TCP under low humidity and be inhibited by water molecules. Hence reaction on NAu-2 is suppressed as relative humidity increases. Whereas, water molecules would reduce the activation and reaction energies via forming a hydrogen bond with reaction intermediates, thus enhancing the reactions on SWy-2 and NAu-1 with less water sensitive structural Fe(III). Considering the wide distribution of Fe(III)-bearing smectites in the environment, the contribution of structural Fe(III) for the formation of more toxic dioxin-like compounds from chlorophenols might need to be taken into consideration to evaluate their potential environmental risks.
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Affiliation(s)
- Yi Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, PR China
| | - Cun Liu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu 210008, PR China
| | - Anping Peng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, PR China
| | - Cheng Gu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, PR China.
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Wang Y, Peng A, Chen Z, Jin X, Gu C. Transformation of gaseous 2-bromophenol on clay mineral dust and the potential health effect. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 250:686-694. [PMID: 31035151 DOI: 10.1016/j.envpol.2019.04.072] [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: 01/26/2019] [Revised: 03/22/2019] [Accepted: 04/15/2019] [Indexed: 06/09/2023]
Abstract
Iron-bearing clays are ubiquitously distributed as mineral dusts in the atmosphere. Bromophenols were reported as the major products from thermal decomposition of the widely used brominated flame retardants (BFRs). However, little information is available for the reactivity of iron associated with mineral dusts to interact with the atmospheric bromophenols and the subsequent toxic effects. Herein, three common clay minerals (montmorillonite, illite and kaolinite) were used to simulate mineral dusts, and the reactions with gaseous 2-bromophenol were systematically investigated under environmentally relevant atmospheric conditions. Our results demonstrate that structural Fe(III) in montmorillonite and Fe(III) from iron oxide in illite mediated the dimerization of 2-bromophenol to form hydroxylated polybrominated biphenyl and hydroxylated polybrominated diphenyl ether. The surface reaction is favored to occur at moisture environment, since water molecules formed complex with 2-bromophenol and the reaction intermediates via hydrogen bond to significantly lower the reaction energy and promote the dimerization reaction. More importantly, the formed dioxin-like products on clay mineral dust increased the toxicity of the particles to A549 lung cell by decreasing cell survival and damaging cellular membrane and proteins. The results of this study indicate that not only mineral dust itself but also the associated surface reaction should be fully considered to accurately evaluate the toxic effect of mineral dust on human health.
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Affiliation(s)
- Yi Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, 210023, PR China
| | - Anping Peng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, 210023, PR China
| | - Zeyou Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, 210023, PR China
| | - Xin Jin
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, 210023, PR China
| | - Cheng Gu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, 210023, PR China.
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Shi X, Zhang R, Li Y, Zhang Q, Xu X, Wang W. Mechanism theoretical study on OH-initiated atmospheric oxidation degradation of dimethoate. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2018.02.104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Zheng J, Zhou Q, Chen C, Jin X, Ma W, Zhang C, Zhou J. Theoretical study on the reactions of a series of polybromobenzenes with OH radicals: mechanism, kinetics, and QSAR. CAN J CHEM 2018. [DOI: 10.1139/cjc-2017-0657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Polybromobenzenes are a kind of monocyclic aromatic flame retardants that are used as a substitute for polybrominated diphenyl ethers and hexabromocyclododecane. In this paper, the reaction mechanism and rate constants for the reaction of OH radicals with a series of polybromobenzenes such as hexabromobenzene (HBB), 1,2,4,5-tetrabromobenzenes (1,2,4,5-TeBB), pentabromobenzene (PEBB), pentabromoethylbenzene (PBEB), pentabromotoluene (PBT), and 2,4,5-tribromotoluene (2,4,5-TrBT) have been investigated by quantum chemical method. The reaction mechanism was obtained at the MPWB1K/6-311+g(3df,2p)//MPWB1K/6-31+g(d,p) level of theory and the rate constants were deduced over the temperature range of 200–370 K using canonical variational transition state (CVT) theory with the small curvature tunneling (SCT) method. The rate constants of OH radicals with HBB, 1,2,4,5-TeBB, PEBB, PBEB, PBT, and 2,4,5-TrBT are determined to be 5.72 × 10−13, 1.23 × 10−12, 8.78 × 10−13, 9.23 × 10−13, 6.46 × 10−13, and 1.69 × 10−12, respectively, at 298 K and 1 atm. The estimated atmospheric lifetimes of HBB (20.08 days), 1,2,4,5-TeBB (9.65 days), PEBB (13.5 days), PBEB (12.9 days), PBT (18.4 days), and 2,4,5-TrBT (7.0 days) determined by OH radicals indicate that polybromobenzenes have the potential for long-range transport. The genetic function approximation is used to study the quantitative structure–activity relationship. The coefficients indicate that the ELUMO has the highest correlation to logkOH.
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Affiliation(s)
- Jian Zheng
- School of Chemistry and Pharmaceutical Engineering, Qilu University of Technology, Jinan 250353, P. R. China
| | - Qin Zhou
- School of Chemistry and Pharmaceutical Engineering, Qilu University of Technology, Jinan 250353, P. R. China
| | - Chao Chen
- School of Chemistry and Pharmaceutical Engineering, Qilu University of Technology, Jinan 250353, P. R. China
| | - Xinhui Jin
- School of Chemistry and Pharmaceutical Engineering, Qilu University of Technology, Jinan 250353, P. R. China
| | - Wanyong Ma
- School of Chemistry and Pharmaceutical Engineering, Qilu University of Technology, Jinan 250353, P. R. China
| | - Chenxi Zhang
- Department of Resources and Environment, Binzhou University, Binzhou 256600, P. R. China
| | - Jianhua Zhou
- School of Chemistry and Pharmaceutical Engineering, Qilu University of Technology, Jinan 250353, P. R. China
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Dong B, Hu J. Photodegradation of the novel fungicide fluopyram in aqueous solution: kinetics, transformation products, and toxicity evolvement. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:19096-19106. [PMID: 27343079 DOI: 10.1007/s11356-016-7073-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 06/13/2016] [Indexed: 06/06/2023]
Abstract
The aqueous photodegradation of fluopyram was investigated under UV light (λ ≥ 200 nm) and simulated sunlight irradiation (λ ≥ 290 nm). The effect of solution pH, fulvic acids (FA), nitrate (NO3 (-)), Fe (III) ions, and titanium dioxide (TiO2) on direct photolysis of fluopyram was explored. The results showed that fluopyram photodegradation was faster in neutral solution than that in acidic and alkaline solutions. The presence of FA, NO3 (-), Fe (III), and TiO2 slightly affected the photodegradation of fluopyram under UV irradiation, whereas the photodegradation rates of fluopyram with 5 mg L(-1) Fe (III) and 500 mg L(-1) TiO2 were about 7-fold and 13-fold faster than that without Fe (III) and TiO2 under simulated sunlight irradiation, respectively. Three typical products for direct photolysis of fluopyram have been isolated and characterized by liquid chromatography tandem mass spectrometry. These products resulted from the intramolecular elimination of HCl, hydroxyl-substitution, and hydrogen extraction. Based on the identified transformation products and evolution profile, a plausible degradation pathway for the direct photolysis of fluopyram in aqueous solution was proposed. In addition, acute toxicity assays using the Vibrio fischeri bacteria test indicated that the transformation products were more toxic than the parent compound.
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Affiliation(s)
- Bizhang Dong
- Laboratory of Pesticide Residues and Environmental Toxicology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China
| | - Jiye Hu
- Laboratory of Pesticide Residues and Environmental Toxicology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China.
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12
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Fernández-Castro P, San Román MF, Ortiz I. Theoretical and experimental formation of low chlorinated dibenzo-p-dioxins and dibenzofurans in the Fenton oxidation of chlorophenol solutions. CHEMOSPHERE 2016; 161:136-144. [PMID: 27424055 DOI: 10.1016/j.chemosphere.2016.07.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 06/15/2016] [Accepted: 07/04/2016] [Indexed: 06/06/2023]
Abstract
The formation of chlorinated and non-chlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) has been experimentally investigated after the Fenton oxidation of 2-chlorophenol (2-CP, 15.56 mM) aqueous solutions by assessing the influence of iron concentration (0.09-2.88 mM), hydrogen peroxide dose (40.44-202.20 mM), temperature (20-70 °C) and chloride concentration (0-56.35 mM). The presence of chloride in the medium together with room temperature and substoichiometric Fenton conditions (40.44 mM H2O2) led to an increase in total PCDD/Fs concentration from less than 1 ng L(-1) to 2 μg L(-1). Results showed a dominance of the dichlorinated species (DCDD/Fs) in the homologue profile of total PCDD/Fs reaching values up to 1.5 μg L(-1). Furthermore, the products distribution exhibited a gradual decrease in the homologue concentration as the chlorination degree increased from di-to octachloro-substituted positions. Considering the characteristics of the reaction medium, the experimental results, and the information gathered in bibliography with regard to the generation of active radicals from 2-chlorophenol, a mechanism describing the formation of low chlorinated PCDD/Fs in a Fenton oxidizing aqueous system has been proposed.
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Affiliation(s)
- Pablo Fernández-Castro
- Departamento de Ingenierías Química y Biomolecular, ETSIIyT, Universidad de Cantabria, Avda. de los Castros, 39005, Santander, Spain
| | - M Fresnedo San Román
- Departamento de Ingenierías Química y Biomolecular, ETSIIyT, Universidad de Cantabria, Avda. de los Castros, 39005, Santander, Spain
| | - Inmaculada Ortiz
- Departamento de Ingenierías Química y Biomolecular, ETSIIyT, Universidad de Cantabria, Avda. de los Castros, 39005, Santander, Spain.
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Liu G, Zhan J, Zhao Y, Li L, Jiang X, Fu J, Li C, Zheng M. Distributions, profiles and formation mechanisms of polychlorinated naphthalenes in cement kilns co-processing municipal waste incinerator fly ash. CHEMOSPHERE 2016; 155:348-357. [PMID: 27135696 DOI: 10.1016/j.chemosphere.2016.04.069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/29/2016] [Accepted: 04/19/2016] [Indexed: 06/05/2023]
Abstract
Co-processing municipal solid waste incinerator (MSWI) fly ash in cement kilns is challenging because the unintentional production of persistent organic pollutants (POPs) during the process is not well understood. The distributions, profiles and formation mechanisms of polychlorinated naphthalenes (PCNs) as new POPs covered under Stockholm Convention in two cement kilns co-processing MSWI fly ash were studied. The average concentrations of PCNs in stack gas samples were 710 ng m(-3). The PCN concentration in particle samples collected from different process stages in the cement kilns ranged from 1.1 to 84.7 ng g(-1). Three process sites including suspension pre-heater boiler, humidifier tower, and the kiln back-end bag filter were identified to be the major formation sites of PCNs in cement kilns co-processing MSWI fly ash. The PCN distribution patterns were similar to that of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/Fs), which indicates the possibility for simultaneous control of PCNs and PCDD/Fs in cement kilns co-processing fly ash. Chlorination was suggested to be an important formation mechanism of PCNs, and chlorination pathways of PCN congeners are proposed based on the congener profiles. Thermodynamic calculations, including relative thermal energies (ΔE) and standard free energy of formation (ΔG), and the charge densities of the carbon atoms in PCN supported the proposed chlorination mechanisms for PCN formation. The results presented in this study might provide helpful information for developing techniques and strategies to control PCN emissions during cement kilns co-processing MSWI fly ash.
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Affiliation(s)
- Guorui Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China
| | - Jiayu Zhan
- State Key Laboratory of Solid Waste Reuse for Building Materials, Beijing Building Materials Academy of Sciences Research, Beijing 100041, China
| | - Yuyang Zhao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China
| | - Li Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China
| | - Xiaoxu Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China
| | - Jianjie Fu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China
| | - Chunping Li
- State Key Laboratory of Solid Waste Reuse for Building Materials, Beijing Building Materials Academy of Sciences Research, Beijing 100041, China
| | - Minghui Zheng
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China; Institute of Environment and Health, Jianghan University, Wuhan 430056, China
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Sun Y, Liu L, Fu X, Zhu T, Buekens A, Yang X, Wang Q. Mechanism of unintentionally produced persistent organic pollutant formation in iron ore sintering. JOURNAL OF HAZARDOUS MATERIALS 2016; 306:41-49. [PMID: 26686523 DOI: 10.1016/j.jhazmat.2015.11.059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 11/27/2015] [Accepted: 11/30/2015] [Indexed: 06/05/2023]
Abstract
Effects of temperature, carbon content and copper additive on formation of chlorobenzenes (CBzs) and polychlorinated biphenyls (PCBs) in iron ore sintering were investigated. By heating simulated fly ash (SFA) at a temperature range of 250-500°C, the yield of both CBzs and PCBs presented two peaks of 637ng/g-fly ash at 350°C and 1.5×10(5)ng/g-fly ash at 450°C for CBzs, and 74ng/g-fly ash at 300°C and 53ng/g-fly ash at 500°C. Additionally, in the thermal treatment of real fly ash (RFA), yield of PCBs displayed two peak values at 350°C and 500°C, however, yield of CBzs showed only one peak at 400°C. In the thermal treatment of SFA with a carbon content range of 0-20wt% at 300°C, both CBzs and PCBs obtained the maximum productions of 883ng/g-fly ash for CBzs and 127ng/g-fly ash for PCBs at a 5wt% carbon content. Copper additives also affected chlorinated aromatic formation. The catalytic activity of different copper additives followed the orders: CuCl2∙2H2O>>Cu2O>Cu>CuSO4>CuO for CBzs, and CuCl2∙2H2O>>Cu2O>CuO>Cu>CuSO4 for PCBs.
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Affiliation(s)
- Yifei Sun
- School of Chemistry and Environment, Beihang University, 37 Xueyuan Road, Beijing, China.
| | - Lina Liu
- School of Energy and Power Engineering, Beihang University, 37 Xueyuan Road, Beijing, China
| | - Xin Fu
- School of Chemistry and Environment, Beihang University, 37 Xueyuan Road, Beijing, China
| | - Tianle Zhu
- School of Chemistry and Environment, Beihang University, 37 Xueyuan Road, Beijing, China
| | - Alfons Buekens
- Department of Chemical Engineering, Free University of Brussels, Pleinlaan 2, 1050 Brussel, Belgium
| | - Xiaoyi Yang
- School of Energy and Power Engineering, Beihang University, 37 Xueyuan Road, Beijing, China
| | - Qiang Wang
- School of Energy and Power Engineering, Beihang University, 37 Xueyuan Road, Beijing, China
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