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Du P, Tang K, Yang B, Mo X, Wang J. Reassessing the Quantum Yield and Reactivity of Triplet-State Dissolved Organic Matter via Global Kinetic Modeling. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:5856-5865. [PMID: 38516968 DOI: 10.1021/acs.est.4c00214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
Measuring the quantum yield and reactivity of triplet-state dissolved organic matter (3DOM*) is essential for assessing the impact of DOM on aquatic photochemical processes. However, current 3DOM* quantification methods require multiple fitting steps and rely on steady-state approximations under stringent application criteria, which may introduce certain inaccuracies in the estimation of DOM photoreactivity parameters. Here, we developed a global kinetic model to simulate the reaction kinetics of the hv/DOM system using four DOM types and 2,4,6-trimethylphenol as the probe for 3DOM*. Analyses of residuals and the root-mean-square error validated the exceptional precision of the new model compared to conventional methods. 3DOM* in the global kinetic model consistently displayed a lower quantum yield and higher reactivity than those in local regression models, indicating that the generation and reactivity of 3DOM* have often been overestimated and underestimated, respectively. The global kinetic model derives parameters by simultaneously fitting probe degradation kinetics under different conditions and considers the temporally increasing concentrations of the involved reactive species. It minimizes error propagation and offers insights into the interactions of different species, thereby providing advantages in accuracy, robustness, and interpretability. This study significantly advances the understanding of 3DOM* behavior and provides a valuable kinetic model for aquatic photochemistry research.
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Affiliation(s)
- Penghui Du
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Kexin Tang
- Center of Water Resources and Environment, School of Civil Engineering, Sun Yat-sen University, Guangzhou, Guangdong 510275, China
| | - Biwei Yang
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Xiaohan Mo
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- School of Urban Planning and Design, Peking University Shenzhen Graduate School, Peking University, Shenzhen, Guangdong 518055, China
| | - Junjian Wang
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
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Li L, Cheng W, Xie X, Zhao R, Wang Y, Wang Z. Photo-Reactivity of dissolved black carbon unveiled by combination of optical spectroscopy and FT-ICR MS analysis: Effects of pyrolysis temperature. WATER RESEARCH 2024; 251:121138. [PMID: 38244298 DOI: 10.1016/j.watres.2024.121138] [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: 09/17/2023] [Revised: 12/29/2023] [Accepted: 01/14/2024] [Indexed: 01/22/2024]
Abstract
Dissolved black carbon (DBC) has high photoactivity, which plays an important role in contaminants photodegradation. However, it is unclear how pyrolysis temperatures would affect the composition and photo-reactivity of DBC at the molecular level. Herein, we combined complementary techniques to study the characteristics of DBC pyrolyzed at 200 - 500 ℃, as well as the photoproduction of reactive species and the photodegradation of tetracycline (TC). Bulk composition characterization found that condensed aromatic carbonyl compounds (ConAC) with narrow molecular weights in DBC experienced an increase from 200 to 500 °C, which enhanced the photoproduction of 3DBC*,1O2, and ·OH. Molecular-level data suggested that 3DBC* and 1O2 were both related to the same DBC compounds. Comparatively, the patterns for ·OH were less pronounced, implying its precursor was not 3DBC* and had more complexity. Plentiful CHOx species of ConAC in DBC400 and DBC500 (DBCT, where T = pyrolysis temperature) accelerated the generation of 3DBC* and 1O2, enhancing the photodegradation of TC, and mainly triplet states of quinones reacted with TC. In contrast, DBC200 and DBC300 exhibited inhibition since massive CHOx species in lignin-like reduced 3TC* to TC. Our data revealed the diverse photochemical behavior mechanisms of DBC pyrolyzed at 200 - 500 ℃ at the molecular level and the implications for aquatic contaminants photochemistry.
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Affiliation(s)
- Liangyu Li
- Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Wan Cheng
- Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Xiaoyun Xie
- Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China.
| | - Ranran Zhao
- Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Yaodong Wang
- Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Zhaowei Wang
- Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China.
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Zhou Y, Lei Y, Kong Q, Lei X, Peng J, Xie Y, Cheng S, Gao Y, Qiu J, Yang X. Reactions of neonicotinoids with peroxydisulfate: The generation of neonicotinoid anion radicals and activation pathway to form sulfate radicals. JOURNAL OF HAZARDOUS MATERIALS 2023; 450:131081. [PMID: 36848840 DOI: 10.1016/j.jhazmat.2023.131081] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/04/2023] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
To activate persulfate to generate reactive species such as sulfate radical (SO4•-) for micropollutants abatement, external energy or chemicals are often needed. In this study, a novel SO4•- formation pathway was reported during the oxidation of neonicotinoids by peroxydisulfate (S2O82-, PDS) without any other chemical additions. Thiamethoxam (TMX) was used as a representative neonicotinoid and SO4•- was the dominant specie contributing to its degradation during PDS oxidation at neutral pH. TMX anion radical (TMX•-) was found to activate PDS to generate SO4•- with the second-order reaction rate constant determined to be (1.44 ± 0.47)× 106 M-1s-1 at pH 7.0 by using laser flash photolysis. TMX•- was generated from the TMX reactions with superoxide radical (O2•-), which was formed from the hydrolysis of PDS. This indirect PDS activation pathway via anion radicals was also applicable to other neonicotinoids. The formation rates of SO4•- were found to negatively linearly correlated with Egap (LUMO-HOMO). The DFT calculations indicated the energy barrier of anion radicals to activate PDS was greatly reduced compared to the parent neonicotinoids. The pathway of anion radicals' activation of PDS to form SO4•- improved the understanding of PDS oxidation chemistry and provided some guidance to enhance oxidation efficiency in field applications.
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Affiliation(s)
- Yangjian Zhou
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Yu Lei
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China; Key Laboratory of Photochemistry, Institute of Chemistry Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences, Beijing 100190, China
| | - Qingqing Kong
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Xin Lei
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Jianglin Peng
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Yufeng Xie
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Shuangshuang Cheng
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Yanpeng Gao
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Junlang Qiu
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China.
| | - Xin Yang
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China.
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Berg SM, Wammer KH, Remucal CK. Dissolved Organic Matter Photoreactivity Is Determined by Its Optical Properties, Redox Activity, and Molecular Composition. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:6703-6711. [PMID: 37039298 PMCID: PMC11095828 DOI: 10.1021/acs.est.3c01157] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Predicting the formation of photochemically produced reactive intermediates (PPRI) during the irradiation of dissolved organic matter (DOM) has remained challenging given the complex nature of this material and differences in PPRI formation mechanisms. We investigate the role of DOM composition in photoreactivity using 48 samples that span the range of DOM in freshwater systems and wastewater. We relate quantum yields for excited triplet-state organic matter (fTMP), singlet oxygen (Φ1O2), and hydroxylating species (Φ•OH) to DOM composition determined using spectroscopy, Fourier-transform ion cyclotron resonance mass spectrometry, and electron-donating capacity (EDC). fTMP and Φ1O2 follow similar trends and are correlated with bulk properties derived from UV-vis spectra and EDC. In contrast, no individual bulk property can be used to predict Φ•OH. At the molecular level, the subset of DOM that is positively correlated to both Φ•OH and EDC is distinct from DOM formulas related to Φ1O2, demonstrating that •OH and 1O2 are formed from different DOM fractions. Multiple linear regressions are used to relate quantum yields of each PPRI to DOM composition parameters derived from multiple techniques, demonstrating that complementary methods are ideal for characterizing DOM because each technique only samples a subset of DOM.
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Affiliation(s)
- Stephanie M. Berg
- Environmental Chemistry and Technology Program, University of Wisconsin – Madison, Madison, Wisconsin 53706
| | - Kristine H. Wammer
- Department of Chemistry, University of St. Thomas, St. Paul, Minnesota 55105
| | - Christina K. Remucal
- Environmental Chemistry and Technology Program, University of Wisconsin – Madison, Madison, Wisconsin 53706
- Department of Civil and Environmental Engineering, University of Wisconsin – Madison, Madison, Wisconsin 53706
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5
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García-Moll L, Sixto A, Carrasco-Correa EJ, Miró M. 3D-printed chemiluminescence flow cells with customized cross-section geometry for enhanced analytical performance. Talanta 2023; 255:124211. [PMID: 36634426 DOI: 10.1016/j.talanta.2022.124211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/18/2022] [Accepted: 12/20/2022] [Indexed: 12/25/2022]
Abstract
Low force stereolithography is exploited for the first time for one-step facile fabrication of chemiluminescence (CL) flow-through cells that bear unrivalled features as compared to those available through milling or blowing procedures or alternative 3D printing technologies. A variety of bespoke cross-section geometries with polyhedral features (namely, triangular, square, and five-side polygon) as well as semicircular cross-section are herein critically evaluated in terms of analytical performance against the standardcircular cross-section in a flat spirally-shape format. The idea behind is to maximize capture of elicited light by the new designs while leveraging 3D printing further for fabrication of (i) customized gaskets that enable reliable attaching of the active mixing zone of the CL cell to the detection window, (ii) in-line 3D-printed serpentine reactors, and (iii) flow confluences with tailorable shapes for enhancing mixing of samples with CL reagents. Up to twenty transparent functional cells were simultaneously fabricated without inner supports following post-curing and surface treatment protocols lasting less than 5 h. In fact, previous attempts to print spirally-shaped cells in one-step by resorting to less cost effective photopolymer inkjet printing technologies were unsuccessful because of the requirement of lengthy procedures (>15 days) for quantitative removal of the support material. By exploiting the phthalazinedione-hydrogen peroxide chemistry as a model reaction, the five-side irregular pentagon cell exhibited superior analytical figures of merit in terms of LOD, dynamic range and intermediate precision as compared to alternative designs. Computational fluid dynamic simulations for mapping velocities at the entry region of the spiral cell corroborated the fact that the 5-side polygon cross-section flow-cell with Y-type confluence permitted the most efficient mixing of reagents and sample while enabling larger flow velocities near the inlet that contribute to a more efficient capture of the photons from the flash-type reaction. The applicability of the 3D-printed 5-side polygon CL cell for automatic determination of hydrogen peroxide using a computerized hybrid flow system was demonstrated for the analysis of high matrix samples, viz., seawater and saliva, with relative recoveries ranging from 83 to 103%.
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Affiliation(s)
- Llucia García-Moll
- FI-TRACE Group, Department of Chemistry, University of the Balearic Islands, Carretera de Valldemossa km 7.5, E-07122, Palma de Mallorca, Spain
| | - Alexandra Sixto
- Cátedra de Química Analítica, Departamento Estrella Campos, Facultad de Química, Universidad de La República, Av. Gral. Flores 2124, 11800, Montevideo, Uruguay
| | - Enrique Javier Carrasco-Correa
- CLECEM Group, Department of Analytical Chemistry, University of Valencia, C/ Doctor Moliner, 50, E-46100, Burjassot, Valencia, Spain.
| | - Manuel Miró
- FI-TRACE Group, Department of Chemistry, University of the Balearic Islands, Carretera de Valldemossa km 7.5, E-07122, Palma de Mallorca, Spain.
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6
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Superoxide Anion Chemistry-Its Role at the Core of the Innate Immunity. Int J Mol Sci 2023; 24:ijms24031841. [PMID: 36768162 PMCID: PMC9916283 DOI: 10.3390/ijms24031841] [Citation(s) in RCA: 35] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 01/09/2023] [Accepted: 01/12/2023] [Indexed: 01/19/2023] Open
Abstract
Classically, superoxide anion O2•- and reactive oxygen species ROS play a dual role. At the physiological balance level, they are a by-product of O2 reduction, necessary for cell signalling, and at the pathological level they are considered harmful, as they can induce disease and apoptosis, necrosis, ferroptosis, pyroptosis and autophagic cell death. This revision focuses on understanding the main characteristics of the superoxide O2•-, its generation pathways, the biomolecules it oxidizes and how it may contribute to their modification and toxicity. The role of superoxide dismutase, the enzyme responsible for the removal of most of the superoxide produced in living organisms, is studied. At the same time, the toxicity induced by superoxide and derived radicals is beneficial in the oxidative death of microbial pathogens, which are subsequently engulfed by specialized immune cells, such as neutrophils or macrophages, during the activation of innate immunity. Ultimately, this review describes in some depth the chemistry related to O2•- and how it is harnessed by the innate immune system to produce lysis of microbial agents.
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Morris JJ, Rose AL, Lu Z. Reactive oxygen species in the world ocean and their impacts on marine ecosystems. Redox Biol 2022; 52:102285. [PMID: 35364435 PMCID: PMC8972015 DOI: 10.1016/j.redox.2022.102285] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 03/07/2022] [Accepted: 03/10/2022] [Indexed: 11/17/2022] Open
Abstract
Reactive oxygen species (ROS) are omnipresent in the ocean, originating from both biological (e.g., unbalanced metabolism or stress) and non-biological processes (e.g. photooxidation of colored dissolved organic matter). ROS can directly affect the growth of marine organisms, and can also influence marine biogeochemistry, thus indirectly impacting the availability of nutrients and food sources. Microbial communities and evolution are shaped by marine ROS, and in turn microorganisms influence steady-state ROS concentrations by acting as the predominant sink for marine ROS. Through their interactions with trace metals and organic matter, ROS can enhance microbial growth, but ROS can also attack biological macromolecules, causing extensive modifications with deleterious results. Several biogeochemically important taxa are vulnerable to very low ROS concentrations within the ranges measured in situ, including the globally distributed marine cyanobacterium Prochlorococcus and ammonia-oxidizing archaea of the phylum Thaumarchaeota. Finally, climate change may increase the amount of ROS in the ocean, especially in the most productive surface layers. In this review, we explore the sources of ROS and their roles in the oceans, how the dynamics of ROS might change in the future, and how this change might impact the ecology and chemistry of the future ocean.
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Couch K, Leresche F, Farmer C, McKay G, Rosario-Ortiz FL. Assessing the source of the photochemical formation of hydroxylating species from dissolved organic matter using model sensitizers. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:102-115. [PMID: 34908096 DOI: 10.1039/d1em00345c] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Dissolved organic matter (DOM) is ubiquitous in natural waters and can facilitate the chemical transformation of many contaminants through the photochemical production of reactive intermediates, such as singlet oxygen (1O2), excited triplet state DOM (3DOM*), and hydroxylating species (˙OH and other intermediates of similar reaction chemistry). The formation mechanism of most reactive intermediates is well understood, but this is not the case for the formation of hydroxylating species from DOM. To investigate this chemistry, DOM model sensitizers were irradiated with two different probe compounds (benzene and benzoic acid) at two irradiation wavelengths (254 and 320 nm). The ability of DOM model sensitizers to hydroxylate these arene probes was assessed by measuring rates of formation of the hydroxylated probe compounds (phenol and salicylic acid). Multiple classes of model sensitizers were tested, including quinones, hydroxybenzoic acids, aromatic ketones, and other triplet forming species. Of these classes of model sensitizers, only quinones and hydroxybenzoic acids had a hydroxylating capacity. Methanol quenching experiments were used to assess the reactivity of hydroxylating species. These results have several implications for the systems tested. First, they suggest that the hydroxylating intermediate produced from hydroxybenzoic acid photolysis may not be hydroxyl radical, but a different hydroxylating species. Also, these data prompted investigation of whether quinone photoproducts have a hydroxylating capacity. These results confirm that hydroxybenzoic acids and quinones are important to the photochemical production of hydroxylating species from DOM, but the mechanism by which this occurs for these classes of sensitizers is still elusive.
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Affiliation(s)
- Kylie Couch
- Department of Civil, Environmental, and Architectural Engineering, Environmental Engineering Program, University of Colorado Boulder, 607 UCB, CO 80309, USA.
| | - Frank Leresche
- Department of Civil, Environmental, and Architectural Engineering, Environmental Engineering Program, University of Colorado Boulder, 607 UCB, CO 80309, USA.
| | - Claire Farmer
- Department of Civil, Environmental, and Architectural Engineering, Environmental Engineering Program, University of Colorado Boulder, 607 UCB, CO 80309, USA.
| | - Garrett McKay
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, 3136 TAMU, College Station, TX 77843, USA.
| | - Fernando L Rosario-Ortiz
- Department of Civil, Environmental, and Architectural Engineering, Environmental Engineering Program, University of Colorado Boulder, 607 UCB, CO 80309, USA.
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Zhao H, Meng B, Sun G, Lin CJ, Feng X, Sommar J. Chemistry and Isotope Fractionation of Divalent Mercury during Aqueous Reduction Mediated by Selected Oxygenated Organic Ligands. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:13376-13386. [PMID: 34520177 DOI: 10.1021/acs.est.1c03171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We have investigated the chemistry and Hg isotope fractionation during the aqueous reduction of HgII by oxalic acid, p-quinone, quinol, and anthraquinone-2,6-disulfonate (AQDS), a derivate of anthraquinone (AQ) that is found in secondary organic aerosols (SOA) and building blocks of natural organic matter (NOM). Each reaction was examined for the effects of light, pH, and dissolved O2. Using an excess of ligand, UVB photolysis of HgII was seen to follow pseudo-first-order kinetics, with the highest rate of ∼10-3 s-1 observed for AQDS and oxalic acid. Mass-dependent fractionation (MDF) occurs by the normal kinetic isotope effect (KIE). Only the oxalate ion, rather than oxalic acid, is photoreactive when present in HgC2O4, which decomposes via two separate pathways distinguishable by isotope anomalies. Upon UVB photolysis, only the reduction mediated by AQDS results in a large odd number mass-independent fractionation (odd-MIF) signified by enrichment of odd isotopes in the reactant. Consistent with the rate, MDF, and odd-MIF reported for fulvic acid, our AQDS result confirms previous assumptions that quinones control HgII reduction in NOM-rich waters. Given the magnitude of odd-MIF triggered via a radical pair mechanism and the significant rate in the presence of air, reduction of HgII by photoproducts of AQDS may help explain the positive odd-MIF observed in ambient aerosols depleted of HgII.
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Affiliation(s)
- Huifang Zhao
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- School of Geography & Environmental Science, Guizhou Normal University, Guiyang 550025, China
| | - Bo Meng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Guangyi Sun
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xian 710061, China
| | - Jonas Sommar
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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Hain E, Adejumo H, Anger B, Orenstein J, Blaney L. Advances in antimicrobial activity analysis of fluoroquinolone, macrolide, sulfonamide, and tetracycline antibiotics for environmental applications through improved bacteria selection. JOURNAL OF HAZARDOUS MATERIALS 2021; 415:125686. [PMID: 34088184 DOI: 10.1016/j.jhazmat.2021.125686] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 02/13/2021] [Accepted: 03/16/2021] [Indexed: 06/12/2023]
Abstract
The widespread use of antibiotics has led to their ubiquitous presence in water and wastewater and raised concerns about antimicrobial resistance. Clinical antibiotic susceptibility assays have been repurposed to measure removal of antimicrobial activity during water and wastewater treatment processes. The corresponding protocols have mainly employed growth inhibition of Escherichia coli. The present work focused on optimizing bacteria selection to improve the sensitivity of residual antimicrobial activity measurements by broth microdilution assays. Thirteen antibiotics from four classes (i.e., fluoroquinolones, macrolides, sulfonamides, tetracyclines) were investigated against three gram-negative organisms, namely E. coli, Mycoplasma microti, and Pseudomonas fluorescens. The minimum inhibitory concentration (MIC) and half-maximal inhibitory concentration (IC50) were calculated for each antibiotic-bacteria pair. P. fluorescens produces a fluorescent siderophore, pyoverdine, that was used to assess sublethal effects and further enhance the sensitivity of antimicrobial activity measurements. The optimal antibiotic-bacteria pairs were as follows: fluoroquinolone-E. coli (growth inhibition); macrolide- and sulfonamide-M. microti (growth inhibition); and, tetracycline-P. fluorescens (pyoverdine inhibition). Compared to E. coli growth inhibition, the sensitivity of antimicrobial activity analysis was improved by up to 728, 19, and 2.7 times for macrolides (tylosin), sulfonamides (sulfamethoxazole), and tetracyclines (chlortetracycline), facilitating application of these bioassays at environmentally-relevant conditions.
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Affiliation(s)
- Ethan Hain
- University of Maryland Baltimore County, Department of Chemical, Biochemical, and Environmental Engineering, 1000 Hilltop Circle, Engineering 314, Baltimore, MD 21250, USA
| | - Hollie Adejumo
- University of Maryland Baltimore County, Department of Chemical, Biochemical, and Environmental Engineering, 1000 Hilltop Circle, Engineering 314, Baltimore, MD 21250, USA; University of Michigan, Department of Civil and Environmental Engineering, 2350 Hayward Street, 2105 GG Brown Building, Ann Arbor, MI 48109-2125, USA
| | - Bridget Anger
- University of Maryland Baltimore County, Department of Chemical, Biochemical, and Environmental Engineering, 1000 Hilltop Circle, Engineering 314, Baltimore, MD 21250, USA
| | - Joseph Orenstein
- University of Maryland Baltimore County, Department of Chemical, Biochemical, and Environmental Engineering, 1000 Hilltop Circle, Engineering 314, Baltimore, MD 21250, USA
| | - Lee Blaney
- University of Maryland Baltimore County, Department of Chemical, Biochemical, and Environmental Engineering, 1000 Hilltop Circle, Engineering 314, Baltimore, MD 21250, USA.
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11
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Thum MD, Hong D, Zeppuhar AN, Falvey DE. Visible-Light Photocatalytic Oxidation of DMSO for RAFT Polymerization †. Photochem Photobiol 2021; 97:1335-1342. [PMID: 34129686 DOI: 10.1111/php.13468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 06/13/2021] [Indexed: 11/28/2022]
Abstract
The solvent is an important, yet often forgotten part of a reaction mechanism. Many photochemical polymerizations are carried out using dimethyl sulfoxide (DMSO) as a way to promote the solubility of both the reactants and products, but its reactivity is rarely considered when initiation mechanisms are proposed. Herein, the oxidation of DMSO by an excited-state quinone is used to form initiating radicals resulting in the polymerization of methacrylate monomers, and the polymerization can be controlled with the addition of a chain transfer agent. This process leads to the formation of polymers with narrow molecular weight distribution, and the polymerization is able to be carried out in the presence of oxygen. A visible light absorbing substituted anthraquinone is synthesized, and nanosecond transient absorption spectroscopy is used to monitor the intermediates involved in the initiation mechanism. Photoproduct analysis indicates formation of methyl radicals as a result of DMSO oxidation. Furthermore, we show that the solvent outcompetes the chain transfer agent for interacting with the excited-state anthraquinone. These observations have a broad impact on photoinduced polymerizations performed in DMSO as many photocatalysts are strong oxidants in the excited state and are capable of reacting with the solvent. Therefore, the role of the solvent needs to be more carefully considered when proposing mechanisms for photoinduced polymerizations in DMSO.
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Affiliation(s)
- Matthew D Thum
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD
| | - Donald Hong
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD
| | - Andrea N Zeppuhar
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD
| | - Daniel E Falvey
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD
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Vital-Grappin AD, Ariza-Tarazona MC, Luna-Hernández VM, Villarreal-Chiu JF, Hernández-López JM, Siligardi C, Cedillo-González EI. The Role of the Reactive Species Involved in the Photocatalytic Degradation of HDPE Microplastics Using C,N-TiO 2 Powders. Polymers (Basel) 2021; 13:999. [PMID: 33805116 PMCID: PMC8037624 DOI: 10.3390/polym13070999] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/21/2021] [Accepted: 03/22/2021] [Indexed: 12/18/2022] Open
Abstract
Microplastics (MPs) are distributed in a wide range of aquatic and terrestrial ecosystems throughout the planet. They are known to adsorb hazardous substances and can transfer them across the trophic web. To eliminate MPs pollution in an environmentally friendly process, we propose using a photocatalytic process that can easily be implemented in wastewater treatment plants (WWTPs). As photocatalysis involves the formation of reactive species such as holes (h+), electrons (e-), hydroxyl (OH●), and superoxide ion (O2●-) radicals, it is imperative to determine the role of those species in the degradation process to design an effective photocatalytic system. However, for MPs, this information is limited in the literature. Therefore, we present such reactive species' role in the degradation of high-density polyethylene (HDPE) MPs using C,N-TiO2. Tert-butanol, isopropyl alcohol (IPA), Tiron, and Cu(NO3)2 were confirmed as adequate OH●, h+, O2●- and e- scavengers. These results revealed for the first time that the formation of free OH● through the pathways involving the photogenerated e- plays an essential role in the MPs' degradation. Furthermore, the degradation behaviors observed when h+ and O2●- were removed from the reaction system suggest that these species can also perform the initiating step of degradation.
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Affiliation(s)
- Aranza Denisse Vital-Grappin
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza C.P. 66455, Nuevo León, Mexico; (A.D.V.-G.); (V.M.L.-H.); (J.M.H.-L.)
| | - Maria Camila Ariza-Tarazona
- Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli 10/1, 41125 Modena, Italy; (M.C.A.-T.); (C.S.)
| | - Valeria Montserrat Luna-Hernández
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza C.P. 66455, Nuevo León, Mexico; (A.D.V.-G.); (V.M.L.-H.); (J.M.H.-L.)
| | - Juan Francisco Villarreal-Chiu
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza C.P. 66455, Nuevo León, Mexico; (A.D.V.-G.); (V.M.L.-H.); (J.M.H.-L.)
- Centro de Investigación en Biotecnología y Nanotecnología (CIByN), Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, Parque de Investigación e Innovación Tecnológica, Km. 10 Autopista al Aeropuerto Internacional Mariano Escobedo, Apodaca 66629, Nuevo León, Mexico
| | - Juan Manuel Hernández-López
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza C.P. 66455, Nuevo León, Mexico; (A.D.V.-G.); (V.M.L.-H.); (J.M.H.-L.)
| | - Cristina Siligardi
- Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli 10/1, 41125 Modena, Italy; (M.C.A.-T.); (C.S.)
| | - Erika Iveth Cedillo-González
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza C.P. 66455, Nuevo León, Mexico; (A.D.V.-G.); (V.M.L.-H.); (J.M.H.-L.)
- Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli 10/1, 41125 Modena, Italy; (M.C.A.-T.); (C.S.)
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Khare P, Machesky J, Soto R, He M, Presto AA, Gentner DR. Asphalt-related emissions are a major missing nontraditional source of secondary organic aerosol precursors. SCIENCE ADVANCES 2020; 6:6/36/eabb9785. [PMID: 32917599 PMCID: PMC7467703 DOI: 10.1126/sciadv.abb9785] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 07/21/2020] [Indexed: 05/14/2023]
Abstract
Asphalt-based materials are abundant and a major nontraditional source of reactive organic compounds in urban areas, but their emissions are essentially absent from inventories. At typical temperature and solar conditions simulating different life cycle stages (i.e., storage, paving, and use), common road and roofing asphalts produced complex mixtures of organic compounds, including hazardous pollutants. Chemically speciated emission factors using high-resolution mass spectrometry reveal considerable oxygen and reduced sulfur content and the predominance of aromatic (~30%) and intermediate/semivolatile organic compounds (~85%), which together produce high overall secondary organic aerosol (SOA) yields. Emissions rose markedly with moderate solar exposure (e.g., 300% for road asphalt) with greater SOA yields and sustained SOA production. On urban scales, annual estimates of asphalt-related SOA precursor emissions exceed those from motor vehicles and substantially increase existing estimates from noncombustion sources. Yet, their emissions and impacts will be concentrated during the hottest, sunniest periods with greater photochemical activity and SOA production.
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Affiliation(s)
- Peeyush Khare
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06511, USA
| | - Jo Machesky
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06511, USA
- Solutions for Energy, Air, Climate and Health (SEARCH), School of Forestry and Environmental Studies, Yale University, New Haven, CT 06511, USA
| | - Ricardo Soto
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06511, USA
| | - Megan He
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06511, USA
| | - Albert A Presto
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Drew R Gentner
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06511, USA.
- Solutions for Energy, Air, Climate and Health (SEARCH), School of Forestry and Environmental Studies, Yale University, New Haven, CT 06511, USA
- Max Planck Institute for Chemistry, Mainz 55128, Germany
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Ma J, Nie J, Zhou H, Wang H, Lian L, Yan S, Song W. Kinetic Consideration of Photochemical Formation and Decay of Superoxide Radical in Dissolved Organic Matter Solutions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:3199-3208. [PMID: 32073838 DOI: 10.1021/acs.est.9b06018] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The photochemical formation and decay rates of superoxide radical ions (O2•-) in irradiated dissolved organic matter (DOM) solutions were directly determined by the chemiluminescent method. Under irradiation, uncatalyzed and catalyzed O2•- dismutation account for ∼25% of the total O2•- degradation in air-saturated DOM solutions. Light-induced O2•- loss, which does not produce H2O2, was observed. Both the O2•- photochemical formation and light-induced loss rates are positively correlated with the electron-donating capacities of the DOM, suggesting that phenolic moieties play a dual role in the photochemical behavior of O2•-. In air-saturated conditions, the O2•- quantum yields of 12 DOM solutions varied in a narrow range, from 1.8 to 3.3‰, and the average was (2.4 ± 0.5)‰. The quantum yield of O2•- nonlinearly increased with increasing dissolved oxygen concentration. Therefore, the quantum yield of one-electron reducing intermediates, the precursor of O2•-, was calculated as (5.0 ± 0.4)‰. High-energy triplets (3DOM*, ET > 200 kJ mol-1) and 1O2 quenching experiments indicate that 3DOM* and 1O2 play minor roles in O2•- production. These results are useful for predicting the photochemical formation and decay of O2•- in sunlit surface waters.
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Affiliation(s)
- Jianzhong Ma
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, P. R. China
| | - JianXin Nie
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, P. R. China
| | - Huaxi Zhou
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, P. R. China
| | - Hui Wang
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, P. R. China
| | - Lushi Lian
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, P. R. China
| | - Shuwen Yan
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, P. R. China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, P. R. China
| | - Weihua Song
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, P. R. China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, P. R. China
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Leyva E, Moctezuma E, Baines KM, Noriega S, Pérez Flores F, Lara‐Pérez C. Identification of intermediate compounds and photodegradation mechanisms of omeprazole under the system UV/O
2. J PHYS ORG CHEM 2019. [DOI: 10.1002/poc.4024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Elisa Leyva
- Facultad de Ciencias QuímicasUniversidad Autónoma de San Luis Potosí San Luis Potosí Mexico
| | - Edgar Moctezuma
- Facultad de Ciencias QuímicasUniversidad Autónoma de San Luis Potosí San Luis Potosí Mexico
| | - Kim M. Baines
- Department of ChemistryUniversity of Western Ontario London Ontario Canada
| | - Saúl Noriega
- Facultad de Ciencias QuímicasUniversidad Autónoma de San Luis Potosí San Luis Potosí Mexico
| | - Francisco Pérez Flores
- Instituto de QuímicaUniversidad Nacional Autónoma de México, Cd. Universitaria, Circuito Exterior Mexico City Mexico
| | - Carmen Lara‐Pérez
- Facultad de Ciencias QuímicasUniversidad Autónoma de San Luis Potosí San Luis Potosí Mexico
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Berg SM, Whiting QT, Herrli JA, Winkels R, Wammer KH, Remucal CK. The Role of Dissolved Organic Matter Composition in Determining Photochemical Reactivity at the Molecular Level. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:11725-11734. [PMID: 31509695 DOI: 10.1021/acs.est.9b03007] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Dissolved organic matter (DOM) composition influences its ability to form photochemically produced reactive intermediates (PPRI). While relationships have been established between bulk DOM properties and triplet DOM (3DOM) and singlet oxygen (1O2) quantum yields, contradictory evidence exists for hydroxyl radical (•OH) and hydroxylating species. Furthermore, little is known about these relationships at the molecular level. We evaluated DOM composition and photochemical reactivity of water samples from a wastewater treatment plant and the St. Louis River in Minnesota and Wisconsin, U.S.A. Bulk characterization using ultraviolet-visible spectroscopy demonstrates that color and apparent size of DOM decrease downstream, while molecular composition analysis using Fourier-transform ion cyclotron resonance mass spectrometry reveals that saturation and chemodiversity is highest near Lake Superior. 3DOM quantum yield coefficients and 1O2 quantum yields increase downstream and correlate strongly with saturated formulas. Similar results are observed for carbon-normalized photodegradation rate constants of atorvastatin, carbamazepine, and venlafaxine, which react primarily with 3DOM and 1O2. In contrast, •OH quantum yields are lowest downstream and correlate with less saturated, more oxygenated DOM, suggesting that 3DOM is not its major precursor. Mixed relationships are observed for DEET, which reacts with multiple PPRI. Molecular-level compositional data reveal insights into the differing formation pathways of individual PPRI, but information about specific contaminants is needed to predict their photochemical fate.
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Affiliation(s)
- Stephanie M Berg
- Environmental Chemistry and Technology Program University of Wisconsin - Madison , Madison , Wisconsin 53706 , United States
| | - Quinn T Whiting
- Department of Chemistry University of St. Thomas , St. Paul , Minnesota 55105 , United States
| | - Joseph A Herrli
- Department of Chemistry University of St. Thomas , St. Paul , Minnesota 55105 , United States
| | - Ronan Winkels
- Department of Chemistry University of St. Thomas , St. Paul , Minnesota 55105 , United States
| | - Kristine H Wammer
- Department of Chemistry University of St. Thomas , St. Paul , Minnesota 55105 , United States
| | - Christina K Remucal
- Environmental Chemistry and Technology Program University of Wisconsin - Madison , Madison , Wisconsin 53706 , United States
- Department of Civil and Environmental Engineering University of Wisconsin - Madison , Madison , Wisconsin 53706 , United States
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Jin J, Zhang S, Wu B, Chen Z, Zhang G, Tratnyek PG. Enhanced Photooxidation of Hydroquinone by Acetylacetone, a Novel Photosensitizer and Electron Shuttle. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:11232-11239. [PMID: 31469553 DOI: 10.1021/acs.est.9b02751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Quinones are important electron shuttles as well as micropollutants in the nature. Acetylacetone (AA) is a newly recognized electron shuttle in aqueous media exposed to UV irradiation. Herein, we studied the interactions between AA and hydroquinone (QH2) under steady-state and transient photochemical conditions to clarify the possible reactions and consequences if QH2 and AA coexist in a solution. Steady-state experimental results demonstrate that the interactions between AA and QH2 were strongly affected by dissolved oxygen. In O2-rich solutions, the phototransformation of QH2 was AA-independent. Both QH2 and AA utilize O2 as the electron acceptor, but in O2-insufficient solutions, AA became an important electron acceptor for the oxidation of QH2. In all cases, the coexistence of AA increased the phototransformation of QH2, whereas the decomposition of AA in O2-saturated and oversaturated solutions was inhibited by the presence of QH2. The underlying mechanisms were investigated by a combination of laser flash photolysis (LFP) and reduction potential analysis. The LFP results show that the excited AA serves as a better electron shuttle than QH2. As a consequence, AA might regulate the redox cycling of quinones, leading to significant effects on many processes, ranging from photosynthesis and respiration to photodegradation.
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Affiliation(s)
- Jiyuan Jin
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , Nanjing 210023 , China
| | - Shujuan Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , Nanjing 210023 , China
| | - Bingdang Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , Nanjing 210023 , China
| | - Zhihao Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , Nanjing 210023 , China
| | - Guoyang Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , Nanjing 210023 , China
| | - Paul G Tratnyek
- OHSU-PSU School of Public Health , Oregon Health & Science University , 3181 SW Sam Jackson Park Road , Portland 97239 , Oregon , United States
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Rong H, Garg S, Waite TD. Impact of light and Suwanee River Fulvic Acid on O 2 and H 2O 2 Mediated Oxidation of Silver Nanoparticles in Simulated Natural Waters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:6688-6698. [PMID: 31090416 DOI: 10.1021/acs.est.8b07079] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this work, we investigate the impact of natural organic matter (NOM) and light on silver nanoparticle (AgNP) dissolution kinetics with particular emphasis on determining the (i) mechanism via which NOM affects the oxidative dissolution of AgNPs, (ii) the role of photogenerated organic radicals and reactive oxygen species (ROS) in oxidative dissolution of AgNPs, and (iii) the mechanism of formation of AgNPs in NOM solution under dark and irradiated conditions. We measured the oxidation of citrate stabilized AgNPs by O2 and hydrogen peroxide (H2O2) in the dark and in irradiated Suwannee River fulvic acid (SRFA) solutions at pH 8.0. Results show that the reactivity of AgNPs toward O2 and H2O2 in the dark decreased in the presence of SRFA as a result of blocking of AgNP surface sites through either steric or electrostatic effects. Irradiation promoted dissolution of AgNPs by O2 and H2O2 in the presence of low concentrations (≤20 mg·L-1) of SRFA as a result of contribution from photogenerated H2O2 formed on irradiation of SRFA as well as photofragmentation of AgNPs. Furthermore, our results show that photogenerated superoxide can induce formation of AgNPs by reducing Ag(I) ions. Based on our experimental results, we have developed a kinetic model to explain AgNP transformation by O2 and H2O2 in the dark and in irradiated SRFA solutions with this model of use in predicting the transformation and fate of AgNPs in natural waters.
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Affiliation(s)
- Hongyan Rong
- UNSW Water Research Center, School of Civil and Environmental Engineering , The University of New South Wales , Sydney , New South Wales NSW 2052 , Australia
| | - Shikha Garg
- UNSW Water Research Center, School of Civil and Environmental Engineering , The University of New South Wales , Sydney , New South Wales NSW 2052 , Australia
| | - T David Waite
- UNSW Water Research Center, School of Civil and Environmental Engineering , The University of New South Wales , Sydney , New South Wales NSW 2052 , Australia
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Huang B, Lai C, Dai H, Mu K, Xu Z, Gu L, Pan X. Microbially reduced humic acid promotes the anaerobic photodegradation of 17α--ethinylestradiol. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 171:313-320. [PMID: 30612019 DOI: 10.1016/j.ecoenv.2018.12.081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 12/07/2018] [Accepted: 12/24/2018] [Indexed: 06/09/2023]
Abstract
Photolysis and microbial activity are relatively obvious in shallow, eutrophic waters with low dissolved oxygen content. Ubiquitous humic acid (HA) can act as electron acceptor and be reduced by bacterial under such conditions, and the reduced form of humic acid (RHA) plays an important role in the photolysis contaminants. In this study, anaerobic 17α-ethinylestradiol (EE2) photodegradation was performed along with biodegradation by Shewanella putrefaciens mediated by HA. The mechanism of such coupled photolysis and biodegradation of EE2 was thus elucidated. The removal rate in such coupled degradation in the presence of 10 mgC L-1 of HA at pH 8.0 was greater than that of either photolysis or biodegradation alone. HA which had been reduced in a double-chamber microbial fuel cell showed better promotion to EE2 photodegradation than fresh HA. Reactive species scavenging experiments indicated that hydroxyl radical and excited triplet states of HA were primary contributors to EE2 photodegradation in anaerobic conditions. More of them were produced from RHA than from pristine HA. Besides, the degraded EE2 solutions inhibited the proliferation of MCF-7 human cancer Cells. These findings improve our understanding of the environmental transformation of EE2 in the shallow, anoxic waters.
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Affiliation(s)
- Bin Huang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Chaochao Lai
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Han Dai
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Kailin Mu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Zhixiang Xu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Lipeng Gu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Xuejun Pan
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China.
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Ma J, Zhou H, Yan S, Song W. Kinetics studies and mechanistic considerations on the reactions of superoxide radical ions with dissolved organic matter. WATER RESEARCH 2019; 149:56-64. [PMID: 30419467 DOI: 10.1016/j.watres.2018.10.081] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 10/23/2018] [Accepted: 10/28/2018] [Indexed: 06/09/2023]
Abstract
Superoxide ion (O2•-) is one of the short lived reactive oxygen species (ROS) formed in aquatic environments. The reactions of O2•- with the model dissolved organic matter (DOM) were studied using a chemiluminescent analysis method under relevant environmental conditions. The reaction of O2•- with DOM produced reduced DOM (DOM•-) by fast one-electron-transfer in the initial stage. This process resulted an initial "loss" in the O2•- decay kinetics. DOM•- is unstable which will continue react with O2•- generating H2O2 to complete a catalytic dismutation cycle. Based on analyzing the observed pseudo-first order O2•- decay rates (kpseudo), the quasi-steady-state concentration of DOM•- is found to be equal to the initial loss of O2•-. Thus, the rate constant for DOM•- with HO2•/O2•- is derived to be (1.1-1.9) × 106 M-1 s-1 in the temperature range of 7.8-41.4 °C. Meanwhile, the apparent rate constant for DOM with O2•- in a flow cell during a short time (2.25 s) is measured as (1.5-3.3) × 103 MC-1 s-1 in the temperature range of 8.2-38.6 °C. These temperature dependent O2•- reaction rate constants present an apparent activation energy of (19.6 ± 2.9) kJ molC-1 for DOM, while that of DOM•- (12.5 ± 3.5 kJ mol-1) is lower. For the pseudo-first order decay rate of O2•-, the catalyzed-dismutation by metal components ranges from 13 to 23%; the contribution by aromatic ketones of DOM is estimated to be 10-13% by using NaBH4 reduction method. The residual contribution might mainly occur at the quinone-like groups, which contributed 64%-77% to the total dismutation. The pH effects on the apparent catalytic rate constants dominate the reaction of O2•- with DOM. The present work suggests that DOM is an important sink for O2•- in aquatic environments. Furthermore, we proposed that the reaction of O2•- with DOM could be a potential source of DOM•- in natural water.
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Affiliation(s)
- Jianzhong Ma
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China
| | - Huaxi Zhou
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China
| | - Shuwen Yan
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200080, PR China
| | - Weihua Song
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200080, PR China.
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Wang K, Garg S, Waite TD. Redox Transformations of Iron in the Presence of Exudate from the Cyanobacterium Microcystis aeruginosa under Conditions Typical of Natural Waters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:3287-3297. [PMID: 28233985 DOI: 10.1021/acs.est.7b00396] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Interaction of the exudate secreted by a toxic strain of the cyanobacterium Microcystis aeruginosa with Fe(II) and Fe(III) was investigated here under both acidic (pH 4) and alkaline (pH 8) conditions. At the concentrations of iron and exudate used, iron was present as dissolved iron (<0.025 μm) at pH 4 but principally as small (<0.45 μm) iron oxyhydroxide particles at pH 8 with only ∼3-27% present in the dissolved form as a result of iron binding by the organic exudate. The formation of strong Fe(III) exudate and relatively weak Fe(II) exudate complexes alters the reduction potential of the Fe(III)-Fe(II) redox couple, facilitating more-rapid oxidation of Fe(II) at pH 4 and 8 than was the case in the absence of exudate. Our results further show that the organic exudate contains Fe(III)-reducing moieties, resulting in the production of measurable concentrations of Fe(II). However, these reducing moieties are short-lived (with a half-life of 1.9 h) and easily oxidized in air-saturated environments. A kinetic model was developed that adequately describes the redox transformation of Fe in the presence of exudate both at pH 4 and pH 8.
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Affiliation(s)
- Kai Wang
- School of Civil and Environmental Engineering, The University of New South Wales , Sydney, NSW 2052, Australia
| | - Shikha Garg
- School of Civil and Environmental Engineering, The University of New South Wales , Sydney, NSW 2052, Australia
| | - T David Waite
- School of Civil and Environmental Engineering, The University of New South Wales , Sydney, NSW 2052, Australia
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Li X, Liu T, Wang K, Waite TD. Light-induced extracellular electron transport by the marine raphidophyte Chattonella marina. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:1392-1399. [PMID: 25569116 DOI: 10.1021/es503511m] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
There is increasing interest in extracellular electron transfer (EET) from organisms to receptors, particularly in anaerobic biofilms at mineral surfaces. Less attention has been given to EET by planktonic organisms in oxic environments where extracellular electron generation and transport might be expected to be of limited consequence. In this study, the EET activity of the photosynthetic marine raphidophyte, Chattonella marina, was examined using a mediatorless photosynthetic microbial fuel cell with results showing positive light response. Electron output by organisms present in cell suspension was substantially higher than those present in biofilms at the electrode surface. Indeed, current generation under light illumination of the C. marina suspension continued even when contact between the organisms and the electrodes was prevented by dialysis membrane, suggesting that soluble electron carriers secreted by C. marina were facilitating the EET process. Cyclic voltammetry measurements of the cell-free exudate showed redox peaks in the range of 0.1-0.5 V (vs Ag/AgCl), confirming that redox active species were present in the cell suspension. Facilitation of electron transfer from the planktonic organism to the anode by endogenous redox-active exudates appears to be critical to current generation. The ability of these exudates to remain in their reduced state in the presence of oxygen is possibly a function of the spin-restricted nature of oxygen-mediated exudate oxidation. Quantification of the EET processes operating in this planktonic system assists in understanding the means and extent to which C. marina induces redox transformations in the external medium with these transformations presumably of benefit to the survival of this organism, potentially including facilitation of iron uptake and induction of toxicity to other organisms.
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Affiliation(s)
- Xiaomin Li
- School of Civil and Environmental Engineering, University of New South Wales , Sydney, New South Wales, Australia 2052
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Sharpless CM, Blough NV. The importance of charge-transfer interactions in determining chromophoric dissolved organic matter (CDOM) optical and photochemical properties. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:654-71. [PMID: 24509887 DOI: 10.1039/c3em00573a] [Citation(s) in RCA: 149] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Absorption of sunlight by chromophoric dissolved natural organic matter (CDOM) is environmentally significant because it controls photic zone depth and causes photochemistry that affects elemental cycling and contaminant fate. Both the optics (absorbance and fluorescence) and photochemistry of CDOM display unusual properties that cannot easily be ascribed to a superposition of individual chromophores. These include (i) broad, unstructured absorbance that decreases monotonically well into the visible and near IR, (ii) fluorescence emission spectra that all fall into a single envelope regardless of the excitation wavelength, and (iii) photobleaching and photochemical quantum yields that decrease monotonically with increasing wavelength. In contrast to a simple superposition model, these phenomena and others can be reasonably well explained by a physical model in which charge-transfer interactions between electron donating and accepting chromophores within the CDOM control the optical and photophysical properties. This review summarizes current understanding of the processes underlying CDOM photophysics and photochemistry as well as their physical basis.
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Affiliation(s)
- Charles M Sharpless
- Department of Chemistry, University of Mary Washington, Fredericksburg, VA 22401, USA.
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25
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Clark CD, de Bruyn W, Jones JG. Photoproduction of hydrogen peroxide in aqueous solution from model compounds for chromophoric dissolved organic matter (CDOM). MARINE POLLUTION BULLETIN 2014; 79:54-60. [PMID: 24445128 DOI: 10.1016/j.marpolbul.2014.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Revised: 12/20/2013] [Accepted: 01/03/2014] [Indexed: 06/03/2023]
Abstract
To explore whether quinone moieties are important in chromophoric dissolved organic matter (CDOM) photochemistry in natural waters, hydrogen peroxide (H2O2) production and associated optical property changes were measured in aqueous solutions irradiated with a Xenon lamp for CDOM model compounds (dihydroquinone, benzoquinone, anthraquinone, napthoquinone, ubiquinone, humic acid HA, fulvic acid FA). All compounds produced H2O2 with concentrations ranging from 15 to 500 μM. Production rates were higher for HA vs. FA (1.32 vs. 0.176 mM h(-1)); values ranged from 6.99 to 0.137 mM h(-1) for quinones. Apparent quantum yields (Θ app; measure of photochemical production efficiency) were higher for HA vs. FA (0.113 vs. 0.016) and ranged from 0.0018 to 0.083 for quinones. Dihydroquinone, the reduced form of benzoquinone, had a higher production rate and efficiency than its oxidized form. Post-irradiation, quinone compounds had absorption spectra similar to HA and FA and 3D-excitation-emission matrix fluorescence spectra (EEMs) with fluorescent peaks in regions associated with CDOM.
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Affiliation(s)
- Catherine D Clark
- School of Earth and Environmental Sciences, Schmid College of Science and Technology, Chapman University, Orange, CA 92866, United States
| | - Warren de Bruyn
- School of Earth and Environmental Sciences, Schmid College of Science and Technology, Chapman University, Orange, CA 92866, United States.
| | - Joshua G Jones
- School of Earth and Environmental Sciences, Schmid College of Science and Technology, Chapman University, Orange, CA 92866, United States
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Garg S, Jiang C, Miller CJ, Rose AL, Waite TD. Iron redox transformations in continuously photolyzed acidic solutions containing natural organic matter: kinetic and mechanistic insights. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:9190-9197. [PMID: 23879362 DOI: 10.1021/es401087q] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this work, the various pathways contributing to the formation and decay of Fe(II) in photolyzed acidic solutions containing Suwannee River fulvic acid (SRFA) are investigated. Results of experimental and computational studies suggest that ligand to metal charge transfer (LMCT), superoxide-mediated iron reduction and interaction with reduced organic species that are present intrinsically in SRFA each contribute to Fe(III) reduction with LMCT the most likely dominant pathway under these conditions. Fe(II) oxidation occurs as a result of its interaction with a variety of light-generated species including (i) short-lived organic species, (ii) relatively stable semiquinone-like organic species, and (iii) hydroperoxy radicals. While not definitive, a hypothesis that the short-lived organic species are similar to peroxyl radicals appears most consistent with our experimental and modeling results. The semiquinone-like organic species formed during photolysis by superoxide-mediated oxidation of reduced organic moieties are long-lived in the dark but prone to rapid oxidation by singlet oxygen ((1)O2) under irradiated conditions and thus play a minor role in Fe(II) oxidation in the light. A kinetic model is developed that adequately describes all aspects of the experimental data obtained and which is capable of predicting Fe(II) oxidation rates and Fe(III) reduction rates in the presence of natural organic matter and light.
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Affiliation(s)
- Shikha Garg
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
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Garg S, Ito H, Rose AL, Waite TD. Mechanism and kinetics of dark iron redox transformations in previously photolyzed acidic natural organic matter solutions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:1861-1869. [PMID: 23331166 DOI: 10.1021/es3035889] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Stable organic species produced on irradiation of Suwannee River Fulvic Acid (SRFA) are shown to be important oxidants of Fe(II) in aqueous solutions at acidic pH, with rate constants substantially larger than those for oxygenation of Fe(II) under the same conditions. These Fe(II)-oxidizing species, which are formed during photolysis by superoxide-mediated oxidation of reduced organic moieties that are present intrinsically in SRFA, are long-lived in the dark but prone to rapid oxidation by singlet oxygen ((1)O(2)) under irradiated conditions. The intrinsic reduced organic species are able to reduce Fe(III) at acidic pH. Although the exact identities of the organic Fe(II) oxidant and the organic Fe(III) reductant are unclear, their behavior is consistent with that expected of semiquinone and hydroquinone-like moieties respectively. A kinetic model is developed that adequately describes all aspects of the experimental data obtained, and which is capable of predicting dark Fe(II) oxidation rates and Fe(III) reduction rates in the presence of previously photolyzed natural organic matter.
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Affiliation(s)
- Shikha Garg
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
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Potential implication of the chemical properties and bioactivity of nitrone spin traps for therapeutics. Future Med Chem 2012; 4:1171-207. [PMID: 22709256 DOI: 10.4155/fmc.12.74] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Nitrone therapeutics has been employed in the treatment of oxidative stress-related diseases such as neurodegeneration, cardiovascular disease and cancer. The nitrone-based compound NXY-059, which is the first drug to reach clinical trials for the treatment of acute ischemic stroke, has provided promise for the development of more robust pharmacological agents. However, the specific mechanism of nitrone bioactivity remains unclear. In this review, we present a variety of nitrone chemistry and biological activity that could be implicated for the nitrone's pharmacological activity. The chemistries of spin trapping and spin adduct reveal insights on the possible roles of nitrones for altering cellular redox status through radical scavenging or nitric oxide donation, and their biological effects are presented. An interdisciplinary approach towards the development of novel synthetic antioxidants with improved pharmacological properties encompassing theoretical, synthetic, biochemical and in vitro/in vivo studies is covered.
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He D, Garg S, Waite TD. H2O2-mediated oxidation of zero-valent silver and resultant interactions among silver nanoparticles, silver ions, and reactive oxygen species. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:10266-10275. [PMID: 22616806 DOI: 10.1021/la300929g] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The H(2)O(2)-mediated oxidation of silver nanoparticles (AgNPs) over a range of pH (3.0-14.0) is investigated here, and an electron charging-discharging model capable of describing the experimental results obtained is developed. AgNPs initially react with H(2)O(2) to form Ag(+) and superoxide, with these products subsequently reacting to reform AgNPs (in-situ-formed AgNPs) via an electron charging-discharging mechanism. Our experimental results show that the AgNP reactivity toward H(2)O(2) varies significantly with pH, with the variation at high pH (>10) due particularly to the differences in the reactivity of H(2)O(2) and its conjugate base HO(2)(-) with AgNPs whereas at lower pH (3-10) the pH dependence of H(2)O(2) decay is accounted for, at least in part, by the pH dependence of the rate of superoxide disproportionation. Our results further demonstrate that the in-situ-formed AgNPs resulting from the superoxide-mediated reduction of Ag(+) have a different size and reactivity compared to those of the citrate-stabilized particles initially present. The turnover frequency for AgNPs varies significantly with pH and is as high as 1776.0 min(-1) at pH 11.0, reducing to 144.2 min(-1) at pH 10.0 and 3.2 min(-1) at pH 3.0.
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Affiliation(s)
- Di He
- School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
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Rose AL. The influence of extracellular superoxide on iron redox chemistry and bioavailability to aquatic microorganisms. Front Microbiol 2012; 3:124. [PMID: 22514548 PMCID: PMC3323869 DOI: 10.3389/fmicb.2012.00124] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 03/15/2012] [Indexed: 11/17/2022] Open
Abstract
Superoxide, the one-electron reduced form of dioxygen, is produced in the extracellular milieu of aquatic microbes through a range of abiotic chemical processes and also by microbes themselves. Due to its ability to promote both oxidative and reductive reactions, superoxide may have a profound impact on the redox state of iron, potentially influencing iron solubility, complex speciation, and bioavailability. The interplay between iron, superoxide, and oxygen may also produce a cascade of other highly reactive transients in oxygenated natural waters. For microbes, the overall effect of reactions between superoxide and iron may be deleterious or beneficial, depending on the organism and its chemical environment. Here I critically discuss recent advances in understanding: (i) sources of extracellular superoxide in natural waters, with a particular emphasis on microbial generation; (ii) the chemistry of reactions between superoxide and iron; and (iii) the influence of these processes on iron bioavailability and microbial iron nutrition.
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Affiliation(s)
- Andrew L. Rose
- Southern Cross GeoScience, Southern Cross UniversityLismore, NSW, Australia
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Golanoski KS, Fang S, Del Vecchio R, Blough NV. Investigating the mechanism of phenol photooxidation by humic substances. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:3912-20. [PMID: 22394372 DOI: 10.1021/es300142y] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
To probe the mechanism of the photosensitized loss of phenols by humic substances (HS), the dependence of the initial rate of 2,4,6-trimethylphenol (TMP) loss (R(TMP)) on dioxygen concentration was examined both for a variety of untreated as well as borohydride-reduced HS and C(18) extracts from the Delaware Bay and Mid-Atlantic Bight. R(TMP) was inversely proportional to dioxygen concentration at [O(2)] > 50 μM, a dependence consistent with reaction with triplet excited states, but not with (1)O(2) or RO(2). Modeling the dependence of R(TMP) on [O(2)] provided rate constants for TMP reaction, O(2) quenching, and lifetimes compatible with a triplet intermediate. Borohydride reduction significantly reduced TMP loss, supporting the role of aromatic ketone triplets in this process. However, for most samples, the incomplete loss of sensitization following borohydride reduction, as well as the inverse dependence of R(TMP) on [O(2)] for these samples, suggests that there remains another class of oxidizing triplet sensitizer, perhaps quinones.
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Affiliation(s)
- Kelli S Golanoski
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
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Li R, Kameda T, Toriba A, Hayakawa K, Lin JM. Determination of Benzo[a]pyrene-7,10-quinone in Airborne Particulates by Using a Chemiluminescence Reaction of Hydrogen Peroxide and Hydrosulfite. Anal Chem 2012; 84:3215-21. [DOI: 10.1021/ac2032063] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Ruibo Li
- State Key
Laboratory of Chemical
Resource Engineering, School of Science, Beijing University of Chemical Technology, Beijing 10029, China
- Graduate School of Natural Science
and Technology, Kanazawa University, Kakuma-machi,
Kanazawa 920-1192, Japan
- Beijing Key Laboratory of Microanalytical
Methods and Instrumentation, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Takayuki Kameda
- Graduate School of Natural Science
and Technology, Kanazawa University, Kakuma-machi,
Kanazawa 920-1192, Japan
| | - Akira Toriba
- Graduate School of Natural Science
and Technology, Kanazawa University, Kakuma-machi,
Kanazawa 920-1192, Japan
| | - Kazuichi Hayakawa
- Graduate School of Natural Science
and Technology, Kanazawa University, Kakuma-machi,
Kanazawa 920-1192, Japan
| | - Jin-Ming Lin
- Beijing Key Laboratory of Microanalytical
Methods and Instrumentation, Department of Chemistry, Tsinghua University, Beijing 100084, China
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33
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Pathways Contributing to the Formation and Decay of Ferrous Iron in Sunlit Natural Waters. ACTA ACUST UNITED AC 2011. [DOI: 10.1021/bk-2011-1071.ch008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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Kim SU, Liu Y, Nash KM, Zweier JL, Rockenbauer A, Villamena FA. Fast reactivity of a cyclic nitrone-calix[4]pyrrole conjugate with superoxide radical anion: theoretical and experimental studies. J Am Chem Soc 2010; 132:17157-73. [PMID: 21070040 PMCID: PMC3121924 DOI: 10.1021/ja105198c] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Nitrone spin traps have been employed as probes for the identification of transient radical species in chemical and biological systems using electron paramagnetic resonance (EPR) spectroscopy and have exhibited pharmacological activity against oxidative-stress-mediated diseases. Since superoxide radical anion (O2(•-)) is a major precursor to most reactive oxygen species and calix[4]pyrroles have been shown to exhibit high affinity to anions, a cyclic nitrone conjugate of calix[4]pyrrole (CalixMPO) was designed, synthesized, and characterized. Computational studies at the PCM/B3LYP/6-31+G(d,p)//B3LYP/6-31G(d) level suggest a pendant-type linkage between the calix[4]pyrrole and the nitrone to be the most efficient design for spin trapping of O2(•-), giving exoergic reaction enthalpies (ΔH(298K,aq)) and free energies (ΔG(298K,aq)) of -16.9 and -2.1 kcal/mol, respectively. (1)H NMR study revealed solvent-dependent conformational changes in CalixMPO leading to changes in the electronic properties of the nitronyl group upon H-bonding with the pyrrole groups as also confirmed by calculations. CalixMPO spin trapping of O2(•-) exhibited robust EPR spectra. Kinetic analysis of O2(•-) adduct formation and decay in polar aprotic solvents using UV-vis stopped-flow and EPR methods gave a larger trapping rate constant for CalixMPO and a longer half-life for its O2(•-) adduct compared to the commonly used nitrones. The unusually high reactivity of CalixMPO with O2(•-) was rationalized to be due to the synergy between the α-effect and electrostatic effect by the calix[4]pyrrole moiety on O2(•-) and the nitrone, respectively. This work demonstrates for the first time the application of an anion receptor for the detection of one of the most important radical intermediates in biological and chemical systems (i.e., O2(•-)).
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Affiliation(s)
- Shang-U Kim
- Department of Pharmacology, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Yangping Liu
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Kevin M. Nash
- Department of Pharmacology, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Jay L. Zweier
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Antal Rockenbauer
- Chemical Research Center, Institute of Structural Chemistry, H-1025 Budapest, Pusztaszeri 59, Hungary
| | - Frederick A. Villamena
- Department of Pharmacology, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
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Vaughan PP, Novotny P, Haubrich N, McDonald L, Cochran M, Serdula J, Amin RW, Jeffrey WH. Bacterial Growth Response to Photoactive Quinones. Photochem Photobiol 2010; 86:1327-33. [DOI: 10.1111/j.1751-1097.2010.00794.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mylon SE, Sun Q, Waite TD. Process optimization in use of zero valent iron nanoparticles for oxidative transformations. CHEMOSPHERE 2010; 81:127-131. [PMID: 20619873 DOI: 10.1016/j.chemosphere.2010.06.045] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Revised: 06/09/2010] [Accepted: 06/10/2010] [Indexed: 05/29/2023]
Abstract
The oxidation of organic compounds in oxygen saturated aqueous suspensions of nanoparticulate zero valent iron (nZVI) is rapidly becoming an area of important consideration for environmental scientists and engineers. Through the production of reactive oxygen species, oxidative processes do occur but have been shown to be of limited efficiency. To increase efficiency for this process, the addition of electron shuttling molecules have been shown to enhance the oxidative capacity of nZVI. Laboratory experiments were conducted at pH 3.0 over a range of nZVI starting concentrations, and the reaction was monitored by following the oxidation of HCOOH and the production of H(2)O(2) with time. These studies confirm that the addition of the polyoxometallates (POM), sodium polyoxotungstate (Na(3)PW(12)O(40)), enhances the oxidative capacity of nZVI. Based on these results, the mechanism for the enhancement in oxidative capacity of nZVI is through two separate processes: (1) the POM out-competes H(2)O(2) for electrons from Fe(0) thereby increasing the H(2)O(2) concentration, and (2) the reduced form of the POM, PW(12)O(40)(-4), facilitates the cycling of Fe(III) to Fe(II) which enhances the homogeneous Fenton reaction.
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Affiliation(s)
- Steven E Mylon
- Department of Chemistry, Lafayette College, Easton, PA 18042, United States
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Fujii M, Rose AL, Omura T, Waite TD. Effect of Fe(II) and Fe(III) transformation kinetics on iron acquisition by a toxic strain of Microcystis aeruginosa. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:1980-1986. [PMID: 20175526 DOI: 10.1021/es901315a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We have investigated the mechanism of Fe uptake by a toxic strain of the freshwater cyanobacterium Microcystis aeruginosa (PCC7806) with particular attention given to the effect of Fe(II) and Fe(III) transformation kinetics on Fe uptake. Chemiluminescence analysis revealed that M. aeruginosa produces extracellular superoxide (a moderate Fe reducing agent) at rates of 0.4-1.2 amol cell(-1) h(-1) depending on initial Fe concentration in the culture medium. Short-term assimilation assays using (55)Fe showed that reduction of Fe(III) in both organic and inorganic forms by cell-generated superoxide or ascorbate facilitated Fe uptake via formation of unchelated Fe(II), when Fe availability was low because of the use of the strong Fe chelator ethylenediaminetetraacetate (EDTA) as a ligand. In contrast, Fe reduction was unimportant for Fe uptake in the presence of low concentrations (< or =100 microM) of the weak Fe-binding ligand citrate because of a high concentration of unchelated Fe(III), indicating that the contribution of reduction to Fe uptake depends on the nature of Fe binding and availability of unchelated Fe(III) in the external medium. A kinetic model incorporating uptake of both unchelated Fe(II) and Fe(III) and based on similar models developed for marine microalgae successfully described Fe uptake rates by M. aeruginosa PCC7806.
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Affiliation(s)
- Manabu Fujii
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
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Liu SY, Lo CT, Shibu MA, Leu YL, Jen BY, Peng KC. Study on the anthraquinones separated from the cultivation of Trichoderma harzianum strain Th-R16 and their biological activity. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2009; 57:7288-7292. [PMID: 19650641 DOI: 10.1021/jf901405c] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The biocontrol fungal species of Trichoderma, which colonizes plant roots, are well-known for their potential to control plant pathogens. Six anthraquinones, of which four have been identified for the first time from Trichoderma and two have already been reported in other strains, were purified from Trichoderma harzianum strain Th-R16 to evaluate their biological activities. The structures of the compounds were determined by one- and two-dimensional NMR. The compounds were shown to exhibit stronger antifungal activity than antibacterial activity. Low yield compounds, like 1,5-dihydroxy-3-hydroxymethyl-9,10-anthraquinone, were found to be more active against fungal pathogens than pachybasin and crysophanol, which were found to be the major extracellular metabolites. Test anthraquinones with higher oxidation numbers had better antifungal activity, and their activities were concentration-dependent.
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Affiliation(s)
- Shu-Ying Liu
- Department of Molecular Biotechnology, Da-Yeh University, Changhua, Taiwan
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WASEEM A, YAQOOB M, NABI A. Photodegradation and Flow-Injection Determination of Dithiocarbamate Fungicides in Natural Water with Chemiluminescence Detection. ANAL SCI 2009; 25:395-400. [DOI: 10.2116/analsci.25.395] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Amir WASEEM
- Department of Chemistry, University of Balochistan
| | | | - Abdul NABI
- Department of Chemistry, University of Balochistan
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