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Xiao K, Wang Z, Zhou Y, Fu D, Zhang Y, Luo Z, Lin Y, Wang Q, Pei J, Shen G. Size-resolved environmentally persistent free radicals in urban road dust and association with transition metals. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2023; 45:7829-7839. [PMID: 37486413 DOI: 10.1007/s10653-023-01688-4] [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: 04/24/2023] [Accepted: 07/11/2023] [Indexed: 07/25/2023]
Abstract
Environmental persistent free radicals (EPFRs) are receiving growing concerns owing to their potentially adverse impacts on human health. Road dust is one important source of air pollution in most cities and may pose significant health risks. Characteristics of EPFRs in urban road dusts and its formation mechanism(s) are still rarely studied. Here, we evaluated occurrence and size distributions of EPFRs in road dusts from different functional areas of an urban city, and assessed relationship between EPFRs and some transition metals. Strong electron paramagnetic resonance signals of 6.01 × 1016 - 1.3 × 1019 spins/g with the mean g value of 2.0029 ± 0.0019 were observed, indicating that EPFRs consisted of a mixture of C-centered radicals, and C-centered radicals with an adjacent oxygen atom in the urban road dust. Much more EPFRs enriched in finer dust particles. EPFRs significantly correlated with the total Fe, but not water-soluble Fe, suggesting different impacts of water-soluble and insoluble metals in the formation of EFPRs. Health risk assessment results indicated high risk potentials via the ingestion and dermal exposure to EPFRs in road dusts. Future studies are calling to look into formation mechanisms of EPFRs in urban road dusts and to quantitatively evaluate its potential risks on human health.
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Affiliation(s)
- Kai Xiao
- College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Zedong Wang
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Yousong Zhou
- College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Donglei Fu
- College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Yongqiang Zhang
- College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Zhihan Luo
- College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Yichun Lin
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Qingyue Wang
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Juan Pei
- Shanghai Nuclear Engineering Research and Design Institute Co., Ltd., No.29 Hongcao Road, Shanghai, 200233, China.
| | - Guofeng Shen
- College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
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2
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Khachatryan L, Barekati-Goudarzi M, Asatryan R, Ozarowski A, Boldor D, Lomnicki SM, Cormier SA. Metal-Free Biomass-Derived Environmentally Persistent Free Radicals (Bio-EPFRs) from Lignin Pyrolysis. ACS OMEGA 2022; 7:30241-30249. [PMID: 36061701 PMCID: PMC9434622 DOI: 10.1021/acsomega.2c03381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 08/04/2022] [Indexed: 06/15/2023]
Abstract
To assess contribution of the radicals formed from biomass burning, our recent findings toward the formation of resonantly stabilized persistent radicals from hydrolytic lignin pyrolysis in a metal-free environment are presented in detail. Such radicals have particularly been identified during fast pyrolysis of lignin dispersed into the gas phase in a flow reactor. The trapped radicals were analyzed by X-band electron paramagnetic resonance (EPR) and high-frequency (HF) EPR spectroscopy. To conceptualize available data, the metal-free biogenic bulky stable radicals with extended conjugated backbones are suggested to categorize as a new type of metal-free environmentally persistent free radicals (EPFRs) (bio-EPFRs). They can be originated not only from lignin/biomass pyrolysis but also during various thermal processes in combustion reactors and media, including tobacco smoke, anthropogenic sources and wildfires (forest/bushfires), and so on. The persistency of bio-EPFRs from lignin gas-phase pyrolysis was outlined with the evaluated lifetime of two groups of radicals being 33 and 143 h, respectively. The experimental results from pyrolysis of coniferyl alcohol as a model compound of lignin in the same fast flow reactor, along with our detailed potential energy surface analyses using high-level DFT and ab initio methods toward decomposition of a few other model compounds reported earlier, provide a mechanistic view on the formation of C- and O-centered radicals during lignin gas-phase pyrolysis. The preliminary measurements using HF-EPR spectroscopy also support the existence of O-centered radicals in the radical mixtures from pyrolysis of lignin possessing a high g value (2.0048).
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Affiliation(s)
- Lavrent Khachatryan
- Department
of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | | | - Rubik Asatryan
- Department
of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Andrew Ozarowski
- National
High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Florida, Tallahassee 32310, United States
| | - Dorin Boldor
- Department
of Biological and Agricultural Engineering, LSU AgCenter and LSU A&M College, Baton Rouge, Louisiana 70803, United States
| | - Slawomir M. Lomnicki
- Department
of Environmental Sciences, Louisiana State
University, Baton Rouge, Louisiana 70803, United States
| | - Stephania A. Cormier
- Department
of Biological Sciences, LSU Superfund Research
Program and Pennington Biomedical Research Center, Baton Rouge, Louisiana 70808, United States
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3
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Feng W, Zhang Y, Huang L, Li Y, Guo Q, Peng H, Shi L. Spatial distribution, pollution characterization, and risk assessment of environmentally persistent free radicals in urban road dust from central China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 298:118861. [PMID: 35063537 DOI: 10.1016/j.envpol.2022.118861] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 01/12/2022] [Accepted: 01/15/2022] [Indexed: 06/14/2023]
Abstract
Environmentally persistent free radicals (EPFRs) have aroused widespread concern due to their potential adverse health effects. Research on EPFRs in road dust is still very limited. In this study, 86 road dust samples were collected using vacuum sampling in a rapidly developing city in central China. The pollution characterization and health risk of EPFRs in the urban road dust were then systematically analyzed. The results showed the average concentrations of EPFRs in urban road dust and fraction of particle with aerodynamic diameters lower than 10 μm (PM10) were 2.24 × 1017 to 3.72 × 1019 spins·g-1 and 6.02 × 1017 to 1.41 × 1020 spins g-1, respectively. The concentrations of EPFRs in dust from expressways, arterial roads, and secondary trunk roads were significantly higher than those found in the remaining road types. The g-factors of 2.0032-2.0039 indicated that the EPFRs have consisted of oxygen-centered and carbon-centered radicals or carbon-centered radicals with nearby oxygen or halogen atoms. Moreover, three decay patterns of EPFRs were observed: a fast decay followed by a slow decay, a single slow decay, and the slowest decay. In addition, a comparative evaluation was made for probabilistic risk assessments of exposure to the EPFRs in road dust and the PM10 fraction. Compared with road dust, the probability of the number of equivalent cigarettes to exceed the 100 and 200 cigarettes for inhaling EPFRs in the PM10 fraction increased by 27.0% and 25.0%, respectively. The simulation results showed the PM10 fraction were primarily deposited in the upper respiratory tract regions (57.1%) and pulmonary regions (28.8%). The findings of this study suggest a potential risk of EPFRs in inhalable particles and provide a new insight for further exploration of the EPFRs in fine particles of road dust.
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Affiliation(s)
- Wenli Feng
- School of Chemistry and Chemical Engineering, Zhoukou Normal University, Zhoukou, 466001, China; Zhoukou Key Laboratory of Environmental Pollution Control and Remediation, Zhoukou Normal University, Zhoukou, 466001, China.
| | - Yongfang Zhang
- School of Chemistry and Chemical Engineering, Zhoukou Normal University, Zhoukou, 466001, China
| | - Liangliang Huang
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin, 541006, China
| | - Yunlin Li
- School of Chemistry and Chemical Engineering, Zhoukou Normal University, Zhoukou, 466001, China; Zhoukou Key Laboratory of Environmental Pollution Control and Remediation, Zhoukou Normal University, Zhoukou, 466001, China
| | - Qingkai Guo
- School of Chemistry and Chemical Engineering, Zhoukou Normal University, Zhoukou, 466001, China
| | - Haoyan Peng
- School of Chemistry and Chemical Engineering, Zhoukou Normal University, Zhoukou, 466001, China
| | - Lei Shi
- School of Environmental and Biological Engineering, Henan University of Engineering, Zhengzhou, 451191, China
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Witwicki M, Lewińska A, Ozarowski A. o-Semiquinone radical anion isolated as an amorphous porous solid. Phys Chem Chem Phys 2021; 23:17408-17419. [PMID: 34351330 DOI: 10.1039/d1cp01596f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The use of metal cations is a commonly applied strategy to create S > 1/2 stable molecular systems containing semiquinone radicals. Persistent mono-semiquinonato complexes of diamagnetic metal ions (S = 1/2) have been hitherto less common and mostly limited to the complexes of heavy metal ions. In this work, a mono-semiquinonato complex of aluminum, derived from 1,2-dihydroxybenzene, is obtained using a surprisingly short and uncomplicated procedure. The isolated product is an amorphous and porous solid that exhibits very good stability under ambient conditions. To characterise its molecular and electronic structure, 9.7, 34 and 406 GHz EPR spectroscopy was used in concert with computational techniques (DFT and DLPNO-CCSD). It was revealed that the radical complex is composed of two chemically equivalent aluminum cations and two catechol-like ligands with the unpaired electron uniformly distributed between the two organic molecules. The good stability and porous structure make this complex applicable in heterogeneous aerobic reactions.
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Affiliation(s)
- Maciej Witwicki
- Faculty of Chemistry, Wroclaw University, Joliot-Curie 14, 50-383 Wroclaw, Poland.
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Shi Y, Zhu K, Dai Y, Zhang C, Jia H. Evolution and stabilization of environmental persistent free radicals during the decomposition of lignin by laccase. CHEMOSPHERE 2020; 248:125931. [PMID: 32000035 DOI: 10.1016/j.chemosphere.2020.125931] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/09/2020] [Accepted: 01/14/2020] [Indexed: 05/28/2023]
Abstract
Soil microbial enzymes may induce lignin decomposition, accompanied by generation of free radicals. The evolution of environmentally persistent free radicals (EPFRs) and reactive oxygen species (ROS) during laccase-catalyzed lignin decomposition remains unclear. Characterization by electron paramagnetic resonance spectroscopy revealed gradually increased concentration of EPFRs, with maximum levels within 6 h that remained constant, accompanied by the increase in g-factor from 2.0037 to 2.0041. The results suggested the generation of oxygen-centered radicals on lignin. The EPFRs produced on solid samples slowly decreased by 17.2% over 17 d. ROS were also detected to have a similar trend as that of the evolution of EPFRs. Scanning electron microscopy, attenuated total reflectance-Fourier transform infrared spectroscopy, gel permeation chromatography and nuclear magnetic resonance analyses suggested the demethylation and oxidation of lignin. We clarify the biogeochemical transformation of lignin and potential contributions to the generation of EPFRs and ROS in soil.
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Affiliation(s)
- Yafang Shi
- College of Natural Resources and Environment, Northwest A & F University, Yangling, 712100, China
| | - Kecheng Zhu
- College of Natural Resources and Environment, Northwest A & F University, Yangling, 712100, China
| | - Yunchao Dai
- College of Natural Resources and Environment, Northwest A & F University, Yangling, 712100, China
| | - Chi Zhang
- College of Natural Resources and Environment, Northwest A & F University, Yangling, 712100, China
| | - Hanzhong Jia
- College of Natural Resources and Environment, Northwest A & F University, Yangling, 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Institute of Soil and Water Conservation, Northwest A & F University, Yangling, 712100, China.
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6
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Huang Y, Song K, Luo W, Yang J. Adsorption and reduction of Cr(VI) by hydroxylated multiwalled carbon nanotubes: effects of humic acid and surfactants. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:12746-12754. [PMID: 32008189 DOI: 10.1007/s11356-020-07682-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 01/07/2020] [Indexed: 06/10/2023]
Abstract
The present study investigated the impacts of humic acid (HA) and surfactants (SDBS and CTAB), which were ubiquitously found in the aquatic environments, on the removal of Cr(VI) by the hydroxylated MWCNTs-OH. The results showed that MWCNTs-OH could remove Cr(VI) from aqueous solution via adsorption coupled with reduction, and the kinetics followed the pseudo-first-order model with the rate of 3.5 × 10-3 h-1. In the presence of anionic SDBS, the removal percentage of Cr(VI) was greatly inhibited because the hydrophobic interaction and π-π interaction between SDBS and MWCNTs-OH surfaces not only decreased the adsorption sites for Cr(VI) but also made the surfaces more negatively charged. On the contrary, the existence of cationic CTAB could lead to the surfaces more positively charged, which consequently enhance the electrostatic attraction between Cr(VI) and the surfaces as well as the removal of Cr(VI). Noticeably, the presence of HA could promote the removal of Cr(VI), which was attributed to the reduction of Cr(VI) by the adsorbed HA. The ESR spectra indicated the existence of π-type radicals in HA structure and conduction electrons in MWCNTs-OH, and then the π-π interaction between MWCNTs-OH and adsorbed HA possibly increase the electron-donating ability of HA. Moreover, the promotive effect of HA could be enhanced with the addition of Ca2+. This study was helpful for us to understand the role of MWCNTs-OH in controlling the fate of Cr(VI) when HA and surfactants were present.
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Affiliation(s)
- Yu Huang
- College of Environmental Science and Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou, 510025, China
| | - Ke Song
- College of Environmental Science and Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou, 510025, China
| | - Wei Luo
- College of Chemistry and Environmental Sciences, Guangdong Ocean University, Zhanjiang, 524088, People's Republic of China
| | - Jiewen Yang
- College of Environmental Science and Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou, 510025, China.
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7
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Zhao S, Miao D, Zhu K, Tao K, Wang C, Sharma VK, Jia H. Interaction of benzo[a]pyrene with Cu(II)-montmorillonite: Generation and toxicity of environmentally persistent free radicals and reactive oxygen species. ENVIRONMENT INTERNATIONAL 2019; 129:154-163. [PMID: 31128436 DOI: 10.1016/j.envint.2019.05.037] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 04/27/2019] [Accepted: 05/14/2019] [Indexed: 05/23/2023]
Abstract
This paper presents the interaction of benzo[a]pyrene (B[a]P) with Cu(II)-montmorillonite to investigate the formation, evolution and potential toxicity of environmentally persistent free radicals (EPFRs) under dark and visible light irradiation conditions. Degradation of B[a]P and the generated transformative products on clay mineral are monitored by gas chromatography-mass spectrometry (GC-MS) technique. Hydroxyl-B[a]P and B[a]P-diones are observed during the transformation of B[a]P under dark condition. B[a]P-3,6-dione and B[a]P-6,12-dione are the main products under visible light irradiation. B[a]P transformation is accompanied by the formation of EPFRs, which are quantified by electron paramagnetic resonance (EPR) spectroscopy. With increasing reaction time, the concentrations of the produced EPFRs are initially increased and then gradually decrease to an undetectable level. The deconvolution results of EPR spectra reveal formation of three types of organic radicals (carbon-centered radicals, oxygen-centered radicals, and carbon-centered radicals with a conjugated oxygen), which also co-exist. Correspondingly, visible-light irradiation promotes the formation and the decay of these EPFRs. The produced B[a]P-type EPFRs induce the generation of reactive oxygen species (ROS), such as superoxide (O2-) and hydroxide radicals (OH), which may cause oxidative stress to cells and tissues of organisms. The toxicity of degradation products is evaluated by the livability of human gastric epithelial GES-1cells. The toxicity is initially increased and then decreases with the elapsed reaction time, which correlates with the evolution of EPFRs concentrations. The present work provides direct evidence that the formation of EPFRs in interaction of PAHs with metal-contaminated clays may result in negative effects to human health.
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Affiliation(s)
- Song Zhao
- College of Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Duo Miao
- College of Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Kecheng Zhu
- College of Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Kelin Tao
- College of Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Chuanyi Wang
- Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, Urumqi 830011, China
| | - Virender K Sharma
- Program for the Environment and Sustainability, Department of Occupational and Environmental Health, School of Public Health, Texas A&M University, College Station, TX 77843, USA.
| | - Hanzhong Jia
- College of Resources and Environment, Northwest A & F University, Yangling 712100, China.
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8
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Barbosa DS, Barbosa DS, Espíndola ELG, Daam MA. The direct effects of a tropical natural humic substance to three aquatic species and its influence on their sensitivity to copper. ECOTOXICOLOGY (LONDON, ENGLAND) 2019; 28:550-558. [PMID: 31119590 DOI: 10.1007/s10646-019-02031-3] [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] [Accepted: 02/22/2019] [Indexed: 06/09/2023]
Abstract
Few studies have been conducted so far into the effects of humic substances (HS) on aquatic organisms and their influence on the toxicity of chemical pollutants in the tropics. The aim of the present study was therefore to evaluate the direct effects of locally-derived tropical natural HS on the cladoceran Daphnia similis, the midge Chironomus xanthus and the fish Danio rerio. The influence of a HS concentration series on the acute toxicity of copper to these organisms was also assessed through laboratory toxicity testing. The HS did not exert direct acute effects on the test organisms, but long-term exposure to higher HS concentrations provoked a stress response (increase in feces production) to D. rerio and exerted effects on chironomid adult emergence and sex ratio. The biotic ligand model proved to be a useful tool in converting total copper concentrations to the appropriate bio-available fraction to which tropical aquatic organisms are exposed.
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Affiliation(s)
- Domingos S Barbosa
- NEEA/CRHEA/SHS, São Carlos Engineering School, University of São Paulo, Av. Trabalhador São Carlense, 400, São Carlos, 13.560-970, Brazil
- Environmental Technology and Management Laboratory (LTGA), Federal University of Mato Grosso, Av. dos Estudantes 5055, Rondonópolis, 78735-901, Brazil
| | - Danilo S Barbosa
- NEEA/CRHEA/SHS, São Carlos Engineering School, University of São Paulo, Av. Trabalhador São Carlense, 400, São Carlos, 13.560-970, Brazil
- Federal Institute of Paraná (IFPR), Rodovia PR 323, km 310, Umuarama, 87.507-014, Brazil
| | - Evaldo L G Espíndola
- NEEA/CRHEA/SHS, São Carlos Engineering School, University of São Paulo, Av. Trabalhador São Carlense, 400, São Carlos, 13.560-970, Brazil
| | - Michiel A Daam
- CENSE, Department of Environmental Sciences and Engineering, Faculty of Sciences and Technology, New University of Lisbon, Quinta da Torre, Caparica, 2829-516, Portugal.
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Nagel M, Seal CE, Colville L, Rodenstein A, Un S, Richter J, Pritchard HW, Börner A, Kranner I. Wheat seed ageing viewed through the cellular redox environment and changes in pH. Free Radic Res 2019; 53:641-654. [PMID: 31092082 DOI: 10.1080/10715762.2019.1620226] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
To elucidate biochemical mechanisms leading to seed deterioration, we studied 23 wheat genotypes after exposure to seed bank storage for 6-16 years compared to controlled deterioration (CD) at 45 °C and 14 (CD14) and 18% (CD18) moisture content (MC) for up to 32 days. Under two seed bank storage conditions, seed viability was maintained in cold storage (CS) at 0 °C and 9% seed MC, but significantly decreased in ambient storage (AS) at 20 °C and 9% MC. Under AS and CS, organic free radicals, most likely semiquinones, accumulated, detected by electron paramagnetic resonance, while the antioxidant glutathione (GSH) was partly lost and partly converted to glutathione disulphide (GSSG), detected by HPLC. Under AS the glutathione half-cell reduction potential (EGSSG/2GSH) shifted towards more oxidising conditions, from -186 to -141 mV. In seeds exposed to CD14 or CD18, no accumulation of organic free radicals was observed, GSH and seed viability declined within 32 and 7 days, respectively, GSSG hardly changed (CD14) or decreased (CD18) and EGSSG/2GSH shifted to -116 mV. The pH of extracts prepared from seeds subjected to CS, AS and CD14 decreased with viability, and remained high under CD18. Across all treatments, EGSSG/2GSH correlated significantly with seed viability (r = 0.8, p<.001). Data are discussed with a view that the cytoplasm is in a glassy state in CS and AS, but during the CD treatments, underwent transition to a liquid state. We suggest that enzymes can be active during CD but not under the seed bank conditions tested. However, upon CD, enzyme-based repair processes were apparently outweighed by deteriorative reactions. We conclude that seed ageing by CD and under seed bank conditions are accompanied by different biochemical reactions.
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Affiliation(s)
| | | | - Louise Colville
- b Department of Comparative Plant and Fungal Biology , Kew , UK
| | - Axel Rodenstein
- c Institute of Inorganic Chemistry , University Leipzig , Leipzig , Germany
| | - Sun Un
- d Department of Biochemistry, Biophysics and Structural Biology , Institute for Integrative Biology of the Cell, I2BC), Université Paris-Saclay , Gif-sur-yvette , France
| | | | | | | | - Ilse Kranner
- e Department of Botany and Center for Molecular Biosciences (CMBI) , University of Innsbruck , Innsbruck , Austria
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Jia H, Zhao S, Shi Y, Zhu K, Gao P, Zhu L. Mechanisms for light-driven evolution of environmentally persistent free radicals and photolytic degradation of PAHs on Fe(III)-montmorillonite surface. JOURNAL OF HAZARDOUS MATERIALS 2019; 362:92-98. [PMID: 30236946 DOI: 10.1016/j.jhazmat.2018.09.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 09/05/2018] [Accepted: 09/06/2018] [Indexed: 05/16/2023]
Abstract
Environmentally persistent free radicals (EPFRs) have been widely detected in superfund sites and atmospheric particles contaminated with organic contaminants, but the impacts of environmental factors such as light irradiation on the formation and evolution of EPFRs remain unclear. In the present study, in-situ irradiated Fourier transform infrared spectrometer and electron paramagnetic resonance were applied to probe the formation mechanisms of EPFRs during photo-transformation of polycyclic aromatic hydrocarbons (PAHs) on montmorillonite surface. EPFRs were only detected on Fe(III)-montmorillonite containing PAHs with relatively high electron-donating ability, such as anthracene (ANT), but not in the systems of Fe(III)-montmorillonite spiked with phenanthrene or Na(I)-montmorillonite. The 1/e lifetime of the EPFRs was much shorter under light irradiation (5.49 h) than in dark (30.3 h), suggesting that light irradiation facilitated the transformation of EPFRs. On the one hand, light irradiation promoted direct electron transfer from ANT to the mineral surface, accelerating the formation of PAHs-type radical cations. On the other hand, light irradiation induced the generation of reactive oxygen species, which facilitated the transformation from radical cations to oxygenic EPFRs, which finally led to ANT degradation. This work clarified the underlying mechanisms for EPFRs generation and evolution on clay minerals.
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Affiliation(s)
- Hanzhong Jia
- College of Resources and Environment, Key Laboratory of Plant Nutrition and The Agri-Environment in Northwest China, Ministry of Agriculture, Northwest A & F University, Yangling 712100, China
| | - Song Zhao
- College of Resources and Environment, Key Laboratory of Plant Nutrition and The Agri-Environment in Northwest China, Ministry of Agriculture, Northwest A & F University, Yangling 712100, China
| | - Yafang Shi
- College of Resources and Environment, Key Laboratory of Plant Nutrition and The Agri-Environment in Northwest China, Ministry of Agriculture, Northwest A & F University, Yangling 712100, China
| | - Kecheng Zhu
- College of Resources and Environment, Key Laboratory of Plant Nutrition and The Agri-Environment in Northwest China, Ministry of Agriculture, Northwest A & F University, Yangling 712100, China
| | - Pin Gao
- College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China.
| | - Lingyan Zhu
- College of Resources and Environment, Key Laboratory of Plant Nutrition and The Agri-Environment in Northwest China, Ministry of Agriculture, Northwest A & F University, Yangling 712100, China.
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Ćwieląg-Piasecka I, Witwicki M, Jerzykiewicz M, Jezierska J. Can Carbamates Undergo Radical Oxidation in the Soil Environment? A Case Study on Carbaryl and Carbofuran. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:14124-14134. [PMID: 29171253 DOI: 10.1021/acs.est.7b03386] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Radical oxidation of carbamate insecticides, namely carbaryl and carbofuran, was investigated with spectroscopic (electron paramagnetic resonance [EPR] and UV-vis) and theoretical (density functional theory [DFT] and ab initio orbital-optimized spin-component scaled MP2 [OO-SCS-MP2]) methods. The two carbamates were subjected to reaction with •OH, persistent DPPH• and galvinoxyl radical, as well as indigenous radicals of humic acids. The influence of fulvic acids on carbamate oxidation was also tested. The results obtained with EPR and UV-vis spectroscopy indicate that carbamates can undergo direct reactions with various radical species, oxidizing themselves into radicals in the process. Hence, they are prone to participate in the prolongation step of the radical chain reactions occurring in the soil environment. Theoretical calculations revealed that from the thermodynamic point of view hydrogen atom transfer is the preferred mechanism in the reactions of the two carbamates with the radicals. The activity of carbofuran was determined experimentally (using pseudo-first-order kinetics) and theoretically to be noticeably higher in comparison with carbaryl and comparable with gallic acid. The findings of this study suggest that the radicals present in soil can play an important role in natural remediation mechanisms of carbamates.
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Affiliation(s)
- Irmina Ćwieląg-Piasecka
- Institute of Soil Science and Environmental Protection, Wroclaw University of Environmental and Life Sciences , Grunwaldzka 53 St., Wroclaw, Poland
| | - Maciej Witwicki
- Faculty of Chemistry, Wroclaw University , 14 F. Joliot-Curie St., 50-383 Wroclaw, Poland
| | - Maria Jerzykiewicz
- Faculty of Chemistry, Wroclaw University , 14 F. Joliot-Curie St., 50-383 Wroclaw, Poland
| | - Julia Jezierska
- Faculty of Chemistry, Wroclaw University , 14 F. Joliot-Curie St., 50-383 Wroclaw, Poland
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Jia H, Zhao S, Nulaji G, Tao K, Wang F, Sharma VK, Wang C. Environmentally Persistent Free Radicals in Soils of Past Coking Sites: Distribution and Stabilization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:6000-6008. [PMID: 28492316 DOI: 10.1021/acs.est.7b00599] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This study presents the existence of environmentally persistent free radicals (EPFRs) in soils of past coking sites, mainly contaminated by polycyclic aromatic hydrocarbons (PAHs). Measurements of EPFRs were conducted by electron paramagnetic resonance (EPR) technique with numerous soil samples, which were collected from different distances (0-1000 m) and different depths (0-30 cm) of three contaminant sources. EPR signals with ∼3 × 1017 radicals/g of the soil samples were obtained, which are very similar to that generated in PAHs contaminated clays, that is, g = 2.0028-2.0036. Concentrations of PAHs and soil components were determined to understand their role in producing EPFRs. PAHs, clay, and iron predominately contributed to generating EPRFs. Meanwhile, organic matter negatively influenced the production of EPRFs. The effects of environmental factors (moisture and oxic/anoxic) were also studied to probe the persistency of EPFRs under various simulated conditions. The EPFRs are stable under relatively dry and oxic conditions. Under anoxic conditions without O2 and H2O, the spin densities decrease initially, followed by gradual increase before attaining constant values in two months period time. The present work implies that continuous formation of EPFRs induced by PAHs is largely responsible for the presence of relatively stable radicals in soils of coking sites.
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Affiliation(s)
- Hanzhong Jia
- Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences , Urumqi 830011, China
| | - Song Zhao
- Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences , Urumqi 830011, China
| | - Gulimire Nulaji
- Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences , Urumqi 830011, China
| | - Kelin Tao
- Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences , Urumqi 830011, China
| | - Fu Wang
- Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences , Urumqi 830011, China
| | - Virender K Sharma
- Program for the Environment and Sustainability, Department of Occupational and Environmental Health, School of Public Health, Texas A&M University , College Station, Texas 77843, United States
| | - Chuanyi Wang
- Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences , Urumqi 830011, China
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Jia H, Nulaji G, Gao H, Wang F, Zhu Y, Wang C. Formation and Stabilization of Environmentally Persistent Free Radicals Induced by the Interaction of Anthracene with Fe(III)-Modified Clays. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:6310-9. [PMID: 27224055 DOI: 10.1021/acs.est.6b00527] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Environmentally persistent free radicals (EPFRs) are occasionally detected in Superfund sites but the formation of EPFRs induced by polycyclic aromatic hydrocarbons (PAHs) is not well understood. In the present work, the formation of EPFRs on anthracene-contaminated clay minerals was quantitatively monitored via electron paramagnetic resonance (EPR) spectroscopy, and surface/interface-related environmental influential factors were systematically explored. The obtained results suggest that EPFRs are more readily formed on anthracene-contaminated Fe(III)-montmorillonite than in other tested systems. Depending on the reaction condition, more than one type of organic radicals including anthracene-based radical cations with g-factors of 2.0028-2.0030 and oxygenic carbon-centered radicals featured by g-factors of 2.0032-2.0038 were identified. The formed EPFRs are stabilized by their interaction with interlayer surfaces, and such surface-bound EPFRs exhibit slow decay with 1/e-lifetime of 38.46 days. Transformation pathway and possible mechanism are proposed on the basis of experimental results and quantum mechanical simulations. Overall, the formation of EPFRs involves single-electron-transfer from anthracene to Fe(III) initially, followed by H2O addition on formed aromatic radical cation. Because of their potential exposure in soil and atmosphere, such clay surface-associated EPFRs might induce more serious toxicity than PAHs and exerts significant impacts on human health.
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Affiliation(s)
- Hanzhong Jia
- Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences , 40-1 South Beijing Road, Urumqi 830011, China
| | - Gulimire Nulaji
- Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences , 40-1 South Beijing Road, Urumqi 830011, China
- School of Geology and Mining Engineering, Xinjiang University , Urumqi 830046, China
| | - Hongwei Gao
- Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences , 40-1 South Beijing Road, Urumqi 830011, China
| | - Fu Wang
- Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences , 40-1 South Beijing Road, Urumqi 830011, China
| | - Yunqing Zhu
- Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences , 40-1 South Beijing Road, Urumqi 830011, China
| | - Chuanyi Wang
- Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences , 40-1 South Beijing Road, Urumqi 830011, China
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Bletsa E, Stathi P, Dimos K, Louloudi M, Deligiannakis Y. Interfacial Hydrogen Atom Transfer by nanohybrids based on Humic Acid Like Polycondensates. J Colloid Interface Sci 2015; 455:163-71. [PMID: 26068375 DOI: 10.1016/j.jcis.2015.05.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 04/08/2015] [Accepted: 05/19/2015] [Indexed: 11/29/2022]
Abstract
Novel nanohybrid materials were prepared by covalent grafting of a polyphenolic polymer [Humic Acid Like Polycondensate (HALP)] on SiO2 nanoparticles. Four nanohybrids were so-produced, using four different types of SiO2 i.e. three Aerosil flame-made nanoparticles with nominal specific surface area of 50, 90 and 300 m(2)/g, herein codenamed OX50, A90, A300 respectively, plus a colloidal SiO2[S300] with SSA=300 m(2)/g. The antioxidant activity of the SiO2-HALP nanohybrids was evaluated by assessing their kinetics for Hydrogen Atom Transfer [HAT] to DPPH radicals. When normalized per same HALP concentration, bigger NPs SiO2[OX50]-HALP NPs can scavenge 280 μmoles of DPPH radicals per gram of HALP, while [A90]-HALP and [A300]-HALP NPs can scavenge 514 and 832 μmoles of DPPH radicals per gram of HALP, respectively. The colloidal SiO2[S300]-HALP can scavenge fewer DPPH radicals (252 μmoles) per gram of HALP. Based on detailed kinetic data it is shown that (i) surface grafted HALPs perform 300% better HAT than non-grafted HALP in solution. (ii) By controlling the particle type and grafting-loading, we can control/optimize the HAT performance: when grafted on the appropriate SiO2 surface the HALP macromolecules are able to quench up to 0.8 mmoles of DPPH-radical per gram of HALP.
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Affiliation(s)
- Eleni Bletsa
- Department of Physics, University of Ioannina, GR-45110 Ioannina, Greece
| | - Panagiota Stathi
- Department of Chemistry, University of Ioannina, GR-45110 Ioannina, Greece
| | - Konstantinos Dimos
- Department of Materials Science & Engineering, University of Ioannina, GR-45110 Ioannina, Greece
| | - Maria Louloudi
- Department of Chemistry, University of Ioannina, GR-45110 Ioannina, Greece
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Bährle C, Nick TU, Bennati M, Jeschke G, Vogel F. High-Field Electron Paramagnetic Resonance and Density Functional Theory Study of Stable Organic Radicals in Lignin: Influence of the Extraction Process, Botanical Origin, and Protonation Reactions on the Radical g Tensor. J Phys Chem A 2015; 119:6475-82. [PMID: 25978006 DOI: 10.1021/acs.jpca.5b02200] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The radical concentrations and g factors of stable organic radicals in different lignin preparations were determined by X-band EPR at 9 GHz. We observed that the g factors of these radicals are largely determined by the extraction process and not by the botanical origin of the lignin. The parameter mostly influencing the g factor is the pH value during lignin extraction. This effect was studied in depth using high-field EPR spectroscopy at 263 GHz. We were able to determine the gxx, gyy, and gzz components of the g tensor of the stable organic radicals in lignin. With the enhanced resolution of high-field EPR, distinct radical species could be found in this complex polymer. The radical species are assigned to substituted o-semiquinone radicals and can exist in different protonation states SH3+, SH2, SH1-, and S2-. The proposed model structures are supported by DFT calculations. The g principal values of the proposed structure were all in reasonable agreement with the experiments.
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Affiliation(s)
- Christian Bährle
- †Paul Scherrer Institut, Research Department General Energy, 5232 Villigen PSI, Switzerland
| | - Thomas U Nick
- ‡Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Marina Bennati
- ‡Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Gunnar Jeschke
- §EPR Research Group, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
| | - Frédéric Vogel
- †Paul Scherrer Institut, Research Department General Energy, 5232 Villigen PSI, Switzerland
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16
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Litvin VA, Minaev BF, Baryshnikov GV. Synthesis and properties of synthetic fulvic acid derived from hematoxylin. J Mol Struct 2015. [DOI: 10.1016/j.molstruc.2014.12.091] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Witwicki M, Jerzykiewicz M, Ozarowski A. Understanding natural semiquinone radicals--multifrequency EPR and relativistic DFT studies of the structure of Hg(II) complexes. CHEMOSPHERE 2015; 119:479-484. [PMID: 25108678 DOI: 10.1016/j.chemosphere.2014.07.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 07/17/2014] [Accepted: 07/19/2014] [Indexed: 06/03/2023]
Abstract
Multifrequency EPR spectroscopy and DFT calculations were used to investigate Hg(II) complexes with semiquinone radical ligands formed in a direct reaction between the metal ions and tannic acid (a polyphenol closely related to tannins). Because of the intricate structure of tannic acid a vast array of substituted phenolic compounds were tested to find a structural model mimicking its ability to react with Hg(II) ions. The components of the g matrix (the g tensor) determined from the high field (208 GHz) EPR spectra of the Hg(II) complexes with the radical ligands derived from tannic acid and from the model compounds were analogous, indicating a similar coordination mode in all the studied Hg(II) complexes. Since catechol (1,2-dihydroxybenzene) was the simplest compound undergoing the reaction with Hg(II) it was selected for DFT studies which were aimed at providing an insight into the structural properties of the investigated complexes. Various coordination numbers and different conformations and protonation states of the ligands were included in the theoretical analyses. g Matrices were computed for all the DFT optimized geometries. A good agreement between the theoretical and experimental values was observed only for the model with the Hg(II) ion tetracoordinated by two ligands, one of the ligands being monoprotonated with the unpaired electron mainly localized on it.
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Affiliation(s)
- Maciej Witwicki
- Faculty of Chemistry, Wroclaw University, Joliot-Curie 14, 50-383 Wroclaw, Poland.
| | - Maria Jerzykiewicz
- Faculty of Chemistry, Wroclaw University, Joliot-Curie 14, 50-383 Wroclaw, Poland.
| | - Andrzej Ozarowski
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310, United States.
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Bährle C, Custodis V, Jeschke G, van Bokhoven JA, Vogel F. In situ observation of radicals and molecular products during lignin pyrolysis. CHEMSUSCHEM 2014; 7:2022-2029. [PMID: 25044866 DOI: 10.1002/cssc.201400079] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 03/21/2014] [Indexed: 06/03/2023]
Abstract
Lignin pyrolysis is a promising method for the sustainable production of phenolic compounds from biomass. However, detailed knowledge about the radicals involved in this process and their influence on the molecular products is missing. Herein, we report on the pyrolysis of hard- and softwood Klason lignins under inert gas conditions in a temperature range between 350-550 °C. During the pyrolysis process, the formed radicals were detected by in situ high-temperature electron paramagnetic resonance spectroscopy. The overall formation of volatile products during lignin pyrolysis was determined using thermogravimetric analysis. The volatile molecular products were characterized and quantified using GC-MS analysis. Major differences were observed between hardwood and softwood lignins. Hardwood lignins form more radicals and volatile products than softwood lignins at temperatures from 350 to 450 °C. In the late stages of the pyrolysis process at 550 °C radical quenching reactions become dominant in hardwood lignins. We identified the disproportionation of two semiquinone radicals to quinone and hydroquinone species as the most likely quenching reaction. Our results show that both the pyrolysis temperature and the type of lignin source have a major influence on radical formation and the molecular products during the depolymerization of lignin.
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Affiliation(s)
- Christian Bährle
- Research Dept. General Energy, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland)
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Šolc R, Gerzabek MH, Lischka H, Tunega D. Radical sites in humic acids: A theoretical study on protocatechuic and gallic acids. COMPUT THEOR CHEM 2014. [DOI: 10.1016/j.comptc.2014.01.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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dela Cruz ALN, Cook RL, Dellinger B, Lomnicki SM, Donnelly KC, Kelley MA, Cosgriff D. Assessment of environmentally persistent free radicals in soils and sediments from three Superfund sites. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:44-52. [PMID: 24244947 PMCID: PMC3907510 DOI: 10.1039/c3em00428g] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We previously reported the presence of environmentally persistent free radicals (EPFRs) in pentachlorophenol (PCP) contaminated soils at a closed wood treatment facility site in Georgia. The reported EPFRs were pentachlorophenoxyl radicals formed on soils under ambient conditions via electron transfer from PCP to electron acceptors in the soil. In this study, we present results for soil and sediment samples from additional Superfund sites in Montana and Washington. Paramagnetic centers associated with different chemical environments were characterized by distinct g-factors and line widths (ΔHp-p). EPFR concentrations in contaminated samples were ~30×, ~12×, and ~2× higher than background samples at the Georgia, Montana, and Washington sites, respectively. EPR signals in the Montana contaminated soils were very similar to those previously observed for pentachlorophenol contaminated soils at the Georgia site, i.e., g = 2.00300 and ΔHp-p = 6.0 G, whereas signals in the Washington sediment samples were similar to those previously observed for other PAH contaminated soils, i.e., g = 2.00270 and ΔHp-p = 9.0 G. Total carbon content measurements exhibited direct correlation with EPFR concentration. The presence of radicals in sites contaminated a decade to a century ago suggests continuous formation of EPFRs from molecular contaminants in the soil and sediment.
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Affiliation(s)
- Albert Leo N dela Cruz
- Louisiana State University, Department of Chemistry, 338 Choppin Hall, Baton Rouge, LA 70803, USA.
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Jerzykiewicz M. Humic and hymatomelanic acids interaction with lanthanide ions. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 96:127-131. [PMID: 22659279 DOI: 10.1016/j.saa.2012.05.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 04/23/2012] [Accepted: 05/03/2012] [Indexed: 06/01/2023]
Abstract
The interactions of lanthanide ions, REE(III), with semiquinone radicals naturally occurring in humic (HA) and hymatomelanic (HY) acids of different origin were studied mainly by EPR spectroscopy. Quantitative EPR analysis proved that only the semiquinone free radical concentration in both, HA and HY, was affected by interaction with some of the lanthanide ions, whereas the EPR g parameters of the formed radical-REE(III) complexes remained unchanged. The radical concentration was practically unaffected by the REE(III) ions with 4f(1)-4f(6) electron configurations and in some degree increased by REE(III) ions with 4f(8)-4f(14) configuration. The lanthanide playing an exceptional role was Gd(III) (4f(7)), which diminished strongly the free radicals concentration. The quenching ability of Gd(III) was stronger towards the radicals provided by HA than by HY, what was assigned to higher content in HA of both, oxygen-containing functional groups and conjugated aromatic rings, leading to more efficient Gd(III)-radical interaction. The semiquinone free radicals of HA and HY originated from the compost were more reactive than those from peat, as the humic acids from mature compost with less bulk density have more accessible functional groups.
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Affiliation(s)
- Maria Jerzykiewicz
- Faculty of Chemistry, Wroclaw University, Joliot-Curie 14, 50-383 Wroclaw, Poland.
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Continuous Wave EPR of Radicals in Solids. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/978-94-007-4893-4_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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Drosos M, Jerzykiewicz M, Louloudi M, Deligiannakis Y. Progress towards synthetic modelling of humic acid: Peering into the physicochemical polymerization mechanism. Colloids Surf A Physicochem Eng Asp 2011. [DOI: 10.1016/j.colsurfa.2011.08.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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dela Cruz ALN, Gehling W, Lomnicki S, Cook R, Dellinger B. Detection of environmentally persistent free radicals at a superfund wood treating site. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:6356-65. [PMID: 21732664 PMCID: PMC3167238 DOI: 10.1021/es2012947] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Environmentally persistent free radicals (EPFRs) have previously been observed in association with combustion-generated particles and airborne PM(2.5) (particulate matter, d < 2.5um). The purpose of this study was to determine if similar radicals were present in soils and sediments at Superfund sites. The site was a former wood treating facility containing pentachlorophenol (PCP) as a major contaminant. Both contaminated and noncontaminated (just outside the contaminated area) soil samples were collected. The samples were subjected to the conventional humic substances (HS) extraction procedure. Electron paramagnetic resonance (EPR) spectroscopy was used to measure the EPFR concentrations and determine their structure for each sample fraction. Analyses revealed a ∼30× higher EPFR concentration in the PCP contaminated soils (20.2 × 10(17) spins/g) than in the noncontaminated soil (0.7 × 10(17) spins/g). Almost 90% of the EPFR signal originated from the minerals/clays/humins fraction. GC-MS analyses revealed ∼6500 ppm of PCP in the contaminated soil samples and none detected in the background samples. Inductively coupled plasma-atomic emission spectrophotometry (ICP-AES) analyses revealed ∼7× higher concentrations of redox-active transition metals, in the contaminated soils than the noncontaminated soil. Vapor phase and liquid phase dosing of the clays/minerals/humins fraction of the soil with PCP resulted in an EPR signal identical to that observed in the contaminated soil, strongly suggesting the observed EPFR is pentachlorophenoxyl radical. Chemisorption and electron transfer from PCP to transition metals and other electron sinks in the soil are proposed to be responsible for EPFR formation.
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Affiliation(s)
- Albert Leo N. dela Cruz
- 413 Choppin Hall, Department of Chemistry, Louisiana State University, Baton Rouge, LA 70802
| | - William Gehling
- 413 Choppin Hall, Department of Chemistry, Louisiana State University, Baton Rouge, LA 70802
| | - Slawomir Lomnicki
- 413 Choppin Hall, Department of Chemistry, Louisiana State University, Baton Rouge, LA 70802
| | - Robert Cook
- 413 Choppin Hall, Department of Chemistry, Louisiana State University, Baton Rouge, LA 70802
| | - Barry Dellinger
- 413 Choppin Hall, Department of Chemistry, Louisiana State University, Baton Rouge, LA 70802
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Zoleo A, Bortolussi C, Brustolon M. Echo detected EPR as a tool for detecting radiation-induced defect signals in pottery. RADIAT MEAS 2011. [DOI: 10.1016/j.radmeas.2011.06.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Trubetskaya OE, Shaloiko LA, Demin DV, Marchenkov VV, Proskuryakov II, Coelho C, Trubetskoj OA. Combining electrophoresis with detection under ultraviolet light and multiple ultrafiltration for isolation of humic fluorescence fractions. Anal Chim Acta 2011; 690:263-8. [DOI: 10.1016/j.aca.2011.02.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 02/02/2011] [Accepted: 02/06/2011] [Indexed: 11/28/2022]
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Witwicki M, Jezierska J. Effects of Solvents, Ligand Aromaticity, and Coordination Sphere on the g Tensor of Anionic o-Semiquinone Radicals Complexed by Mg2+ Ions: DFT Studies. J Phys Chem B 2011; 115:3172-84. [DOI: 10.1021/jp110515j] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Maciej Witwicki
- Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie St., Wroclaw 50-283, Poland
| | - Julia Jezierska
- Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie St., Wroclaw 50-283, Poland
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Christoforidis KC, Un S, Deligiannakis Y. Effect of metal ions on the indigenous radicals of humic acids: high field electron paramagnetic resonance study. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:7011-7016. [PMID: 20715767 DOI: 10.1021/es101708f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The interaction of indigenous radicals of humic acid (HA) with metal cations has been studied using high magnetic field (10.5T-285 GHz) electron paramagnetic resonance (HFEPR) spectroscopy. Strong [HA]-[metal] interaction was observed in the case of heavy metals, Cd(2+), Pb(2+), and Sr(2+), leading to formation of covalent bonds with the radicals of HA. On the contrary, alkaline earth metal ions, such as Mg(2+), generate only electrostatic interaction. The two types of indigenous radicals that exist in all HAs are influenced by the metal cations in a unified manner. This provides evidence that the two types of indigenous radicals in HAs originate from a unique, phenolic, moiety in HA. Mg(2+) ions dramatically changed the pH profile of the two radical types of HA, downshifting their interconversion pK(a) by ca. 3 pH units. This is the first experimental observation of the effect of metals on the H-dissociation of the radical centers in HAs.
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Affiliation(s)
- Konstantinos C Christoforidis
- Laboratory of Physical Chemistry, Department of Environmental and Natural Resources Management, University of Ioannina, Seferi 2, 30100 Agrinio, Greece
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Witwicki M, Jezierska J. Protic and aprotic solvent effect on molecular properties and g-tensors of o-semiquinones with various aromacity and heteroatoms: A DFT study. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.05.063] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Witwicki M, Jerzykiewicz M, Jaszewski AR, Jezierska J, Ozarowski A. Influence of Pb(II) Ions on the EPR Properties of the Semiquinone Radicals of Humic Acids and Model Compounds: High Field EPR and Relativistic DFT Studies. J Phys Chem A 2009; 113:14115-22. [DOI: 10.1021/jp906289d] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Maciej Witwicki
- Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie Street, Wroclaw 50-283, Poland, and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310
| | - Maria Jerzykiewicz
- Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie Street, Wroclaw 50-283, Poland, and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310
| | - Adrian R. Jaszewski
- Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie Street, Wroclaw 50-283, Poland, and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310
| | - Julia Jezierska
- Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie Street, Wroclaw 50-283, Poland, and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310
| | - Andrzej Ozarowski
- Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie Street, Wroclaw 50-283, Poland, and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310
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Giannakopoulos E, Drosos M, Deligiannakis Y. A humic-acid-like polycondensate produced with no use of catalyst. J Colloid Interface Sci 2009; 336:59-66. [DOI: 10.1016/j.jcis.2009.03.037] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 03/12/2009] [Accepted: 03/13/2009] [Indexed: 10/20/2022]
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Panagiota S, Louloudi M, Deligiannakis Y. EPR study of phenolic radical stabilization by grafting on SiO2. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.02.080] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Solvent effect on EPR, molecular and electronic properties of semiquinone radical derived from 3,4-dihydroxybenzoic acid as model for humic acid transient radicals: High-field EPR and DFT studies. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.03.035] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Witwicki M, Jaszewski AR, Jezierska J, Jerzykiewicz M, Jezierski A. The pH-induced shift in the g-tensor components of semiquinone-type radicals in humic acids – DFT and EPR studies. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.07.086] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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