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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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2
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Yu J, Huo R, Liu W, Wen X. Chemodiversity transformation of organic matters in a full scale MBR-NF wastewater reclamation plant. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166246. [PMID: 37582448 DOI: 10.1016/j.scitotenv.2023.166246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 08/01/2023] [Accepted: 08/10/2023] [Indexed: 08/17/2023]
Abstract
Membrane bioreactor (MBR) and nanofiltration (NF) process has been attractive in wastewater reclamation, and was set as the target process in this study. Dissolved organic matter (DOM) and trace organic contaminants (TrOCs), closely associated with water safety, are noteworthy pollutants. Though the general DOM characteristics and TrOCs removal in MBR-NF reclamation process have been reported in lab-/pilot-scale experiment, the molecular characteristics of DOM revealed by high resolution mass spectrometry, and the correlation between DOM and TrOCs have been rarely studied in full-scale MBR-NF wastewater reclamation plant. In this work, biological and NF processes contributed significantly to the removal of DOM and TrOCs, while MBR filtration contributed slightly. Spectroscopic analyses revealed that DOM with higher aromaticity and lower molecular weight were more recalcitrant along the treatment. Aromatic protein-like substances were preferentially removed comparing to humic-like substances. Fourier transform ion cyclotron resonance mass spectrometry was applied to investigate DOM transformation at molecular level. DOM molecules with higher H/C and lower O/C, especially the aliphatics and peptides, were readily biodegraded into higher‑oxygenate, highly unsaturated, and aromatic compounds. The generated species mainly included condensed aromatics, polyphenols, and highly unsaturated compounds. Filtration in MBR tended to reject higher oxygenated molecules. NF effectively removed most of the DOM molecules, especially higher oxygenated molecules with low H, N and S. The residual TrOCs in the NF effluent, including sulfamethoxazole, ofloxacin, and bisphenol A, still displayed above medium environmental risk. Significant correlations were found among organic compounds, spectral indices, and peptides molecules. Positive correlation between most of the TrOCs and several DOM parameters implied that they were synchronously removed in biological and membrane filtration processes. SUVA and FI might be potential indexes in monitoring the performance of MBR-NF process in both DOM and TrOC removal. These findings would expand the understanding of DOM and TrOCs behavior in wastewater reclamation process and simplify an in-depth system monitoring.
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Affiliation(s)
- Jinlan Yu
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Ran Huo
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Wei Liu
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Xianghua Wen
- School of Environment, Tsinghua University, Beijing 100084, China.
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Jin Y, Zhang X, Yuan Y, Lan Y, Cheng K, Yang F. Synthesis of artificial humic acid-urea complex improves nitrogen utilization. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 344:118377. [PMID: 37348301 DOI: 10.1016/j.jenvman.2023.118377] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/27/2023] [Accepted: 06/10/2023] [Indexed: 06/24/2023]
Abstract
The inefficient use of conventional nitrogen (N) fertilizers leads to N enrichment in the soil, resulting in N loss via runoff, volatilization and leaching. While using artificial humic acid to prepare novel N fertilizer is a good choice to improve its efficiency, the high heterogeneity of artificial humic acid limits its structural analysis and utilization efficiency. To solve above problems, this work mainly carried out the fractionation experiments, melt penetration experiments and soil incubation experiments. The results revealed that four fractions with different aromatization degree and molecular weights were obtained by the newly proposed continuous dissolution method, particular in the extraction solution of pH = 3-4, which were extracted with the highest aromatization degree. Furthermore, artificial humic acid urea complex fertilizers prepared at pH = 3-4 significantly improved the release of NH4+-N by 38.32% on days 7 and NO3--N by 10.30% on days 14, compared to urea application. The highly aromatic complex fertilizer with loading of urea-N was able to supply more inorganic N to the soil on days 3-14 (low molecular weight N) and to maintain a higher N content on days 70 (highly aromatized N). This can partially offset the mineralization of readily available organic N, buffering the immobilization of inorganic N from the soil when unstable organic compounds (e.g. conventional urea) were incorporated. A-HAU3-4 addition on days 70, Proteobacteria and Actinobacteriota were found to be the dominant phylum in the soil and the relative abundance of Endophytic bacteria was increased, which was conducive to the improvement of soil N utilization efficiency and soil N sequestration. Therefore, the preparation of artificial humic urea fertilizer with high aromatization degree or low molecular weight were an effective way to improve N utilization efficiency in the initial stages of soil incubation and maintain N fixation in the later stages of soil incubation. The future application of the strategy presented by this study would have an important ecological significance for alleviating agricultural N pollution.
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Affiliation(s)
- Yongxu Jin
- School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin, 150030, China; Heilongjiang Provincial International Joint Laboratory of Smart Soil, Harbin, 150030, China
| | - Xi Zhang
- School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin, 150030, China; Heilongjiang Provincial International Joint Laboratory of Smart Soil, Harbin, 150030, China
| | - Yue Yuan
- School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin, 150030, China; Heilongjiang Provincial International Joint Laboratory of Smart Soil, Harbin, 150030, China
| | - Yibo Lan
- School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin, 150030, China; Heilongjiang Provincial International Joint Laboratory of Smart Soil, Harbin, 150030, China
| | - Kui Cheng
- Heilongjiang Provincial International Joint Laboratory of Smart Soil, Harbin, 150030, China; College of Engineering, Northeast Agricultural University, Harbin, 150030, China.
| | - Fan Yang
- School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin, 150030, China; Heilongjiang Provincial International Joint Laboratory of Smart Soil, Harbin, 150030, China.
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4
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Chen X, Wang J, Wu H, Zhu Z, Zhou J, Guo H. Trade-off effect of dissolved organic matter on degradation and transformation of micropollutants: A review in water decontamination. JOURNAL OF HAZARDOUS MATERIALS 2023; 450:130996. [PMID: 36867904 DOI: 10.1016/j.jhazmat.2023.130996] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 01/24/2023] [Accepted: 02/09/2023] [Indexed: 06/18/2023]
Abstract
The degradation of micropollutants by various treatments is commonly affected by the ubiquitous dissolved organic matter (DOM) in the water environment. To optimize the operating conditions and decomposition efficiency, it is necessary to consider the impacts of DOM. DOM exhibits varied behaviors in diverse treatments, including permanganate oxidation, solar/ultraviolet photolysis, advanced oxidation processes, advanced reduction process, and enzyme biological treatments. Besides, the different sources (i.e., terrestrial and aquatic, etc) of DOM, and operational circumstances (i.e., concentration and pH) fluctuate different transformation efficiency of micropollutants in water. However, so far, systematic explanations and summaries of relevant research and mechanism are rare. This paper reviewed the "trade-off" performances and the corresponding mechanisms of DOM in the elimination of micropollutants, and summarized the similarities and differences for the dual roles of DOM in each of the aforementioned treatments. Inhibition mechanisms typically include radical scavenging, UV attenuation, competition effect, enzyme inactivation, reaction between DOM and micropollutants, and intermediates reduction. Facilitation mechanisms include the generation of reactive species, complexation/stabilization, cross-coupling with pollutants, and electron shuttle. Moreover, electron-drawing groups (i.e., quinones, ketones functional groups) and electron-supplying groups (i.e., phenols) in the DOM are the main contributors to its trade-off effect.
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Affiliation(s)
- Xingyu Chen
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Jingquan Wang
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Han Wu
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Zhuoyu Zhu
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Jianfei Zhou
- National Engineering Research Center of Clean Technology in Leather Industry, Sichuan University, Chengdu 610065, China.
| | - Hongguang Guo
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China; Yibin Industrial Technology Research Institute of Sichuan University, Yibin 644000, China.
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5
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Zhang T, Ma H, Hong Z, Fu G, Zheng Y, Li Z, Cui F. Photo-Reactivity and Photo-Transformation of Algal Dissolved Organic Matter Unraveled by Optical Spectroscopy and High-Resolution Mass Spectrometry Analysis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:13439-13448. [PMID: 36069735 DOI: 10.1021/acs.est.2c03524] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The rapid proliferation of planktonic algae induced by eutrophication and climate warming make algae dissolved organic matter (AOM) an important source of dissolved organic matter (DOM) in surface waters, but the understanding of the link between AOM composition and photo-reactivity/photo-transformation of DOM in aquatic systems is limited. Here, intracellular organic matter (IOM) from Microcystis aeruginosa was extracted and subjected to molecular weight (MW) fractionation. Results indicated that IOM had lower aromaticity and higher photosensitive activity compared to Suwannee River fulvic acid (SRFA). The photosensitive activity of IOM relied on both its molecular weight distribution and fluorescence components. The IOM fraction with the highest MW proteins had the lowest quantum yields of reactive intermediates (ΦRIs), which increased with the decrease of MW, while the fractions with more low-excitation tyrosine-like components had relatively higher ΦRIs. Parallel factor analysis and high-resolution mass spectrometry revealed that light radiation of IOM resulted in the composition transformation from tryptophan-like and tyrosine-like components to humic-like components, forming less aromatic and more saturated recalcitrant dissolved organic carbon. Our findings provide new insights into the photo-reactivity and photo-transformation of algae-derived organic matters and help to predict DOM formation involved in carbon cycling in water environment.
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Affiliation(s)
- Ting Zhang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, College of Environment and Ecology, Chongqing University, No.174 Shazhengjie, Shapingba, Chongqing 400044, China
| | - Hua Ma
- Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, College of Environment and Ecology, Chongqing University, No.174 Shazhengjie, Shapingba, Chongqing 400044, China
| | - Zhicheng Hong
- Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, College of Environment and Ecology, Chongqing University, No.174 Shazhengjie, Shapingba, Chongqing 400044, China
| | - Guoqing Fu
- Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, College of Environment and Ecology, Chongqing University, No.174 Shazhengjie, Shapingba, Chongqing 400044, China
| | - Yun Zheng
- Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, College of Environment and Ecology, Chongqing University, No.174 Shazhengjie, Shapingba, Chongqing 400044, China
| | - Zhe Li
- Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, College of Environment and Ecology, Chongqing University, No.174 Shazhengjie, Shapingba, Chongqing 400044, China
| | - Fuyi Cui
- Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, College of Environment and Ecology, Chongqing University, No.174 Shazhengjie, Shapingba, Chongqing 400044, China
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6
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Tu Y, Liu H, Li Y, Zhang Z, Lei Y, Zhao Q, Tian S. Radical chemistry of dissolved black carbon under sunlight irradiation: quantum yield prediction and effects on sulfadiazine photodegradation. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:21517-21527. [PMID: 34766222 DOI: 10.1007/s11356-021-17379-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/01/2021] [Indexed: 06/13/2023]
Abstract
Dissolved black carbon (DBC) is regarded as an important part of the natural organic matter pool. However, it is unclear about DBC's photochemical activity and the relationships between reactive intermediates (RIs) and the molecular structure of DBC remain unclear. In this study, we investigate the photochemical formation ability of RIs and spectral parameters (E2/E3, S275-295) of DBC made from five types of plants at five pyrolysis temperatures. The results showed that there were good linear regressions between the RI quantum yields and the spectral parameters (E2/E3, S275-295), and this was indicative of the RI generation prediction from DBC under solar irradiation. The DBC-mediated photochemical experiment of sulfadiazine revealed that 3DBC* was the primary active species for the indirect photodegradation of sulfadiazine. Further studies indicated that a linear relationship was observed between the indirect photodegradation ability of sulfadiazine induced directly by 3DBC* at different pyrolysis temperatures and the 3DBC* quantum yields or E2/E3. These findings indicate that the simple models of the RI quantum yield as a function of spectral parameters can be used to evaluate the degradation of pollutants with known DBC spectral parameters.
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Affiliation(s)
- Yina Tu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China
| | - Huaying Liu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China
| | - Yingjie Li
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China.
| | - Zhiyu Zhang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China
| | - Yajie Lei
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China
| | - Qun Zhao
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China
| | - Senlin Tian
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, Yunnan, China.
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Wang Y, Gong X, Dong X. Photo-oxidation of arsenite in acidic waters containing Suwannee River fulvic acid: roles of 3SRFA* and hydroxyl radical. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:45144-45154. [PMID: 33864218 DOI: 10.1007/s11356-021-13900-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
The photo-oxidation of arsenite (As(III)) in solution containing Suwannee River fulvic acid (SRFA) under the ultraviolet A (UVA) irradiation (λmax = 365 nm) was studied. In a solution containing 100.0 μg·L-1 As(III) and 10.0 mg·L-1 SRFA at pH 3.0, SRFA induced As(III) photo-oxidation by producing the triplet excited state of SRFA (3SRFA*) and hydroxyl radical(HO˙). Approximately 82% of As(III) oxidation was attributed to HO˙ which depended strongly on HO2˙/O2˙-. The remaining 18% of As(III) oxidation was attributed to the direct reaction between As(III) and 3SRFA*. The photo-oxidation of As(III) was significantly affected by solution pH. Excess SRFA inhibited As(III) photo-oxidation. The addition of a low concentration of ferric ions retarded the photo-oxidation of As(III) due to the poor photo-activity of Fe(III)-SRFA complexes. In contrast, the addition of ferric ions at high concentration greatly accelerated As(III) photo-oxidation because of the high photo-activity of Fe(III)-OH complexes. The fractions of SRFA with different molecular weight showed different oxidizing capacities under UV irradiation which was possibly related to the different contents of phenolic OH groups. The findings have important environmental implications for the photo-transformation behavior of As(III) in natural surface waters containing dissolved organic matter, especially acidic waters.
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Affiliation(s)
- Yajie Wang
- School of Eco-Environmental Engineering, Guizhou Minzu University, Guiyang, 550025, People's Republic of China.
| | - Xianhe Gong
- School of Eco-Environmental Engineering, Guizhou Minzu University, Guiyang, 550025, People's Republic of China
| | - Xin Dong
- School of Eco-Environmental Engineering, Guizhou Minzu University, Guiyang, 550025, People's Republic of China
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8
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Shi W, Zhuang WE, Hur J, Yang L. Monitoring dissolved organic matter in wastewater and drinking water treatments using spectroscopic analysis and ultra-high resolution mass spectrometry. WATER RESEARCH 2021; 188:116406. [PMID: 33010601 DOI: 10.1016/j.watres.2020.116406] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/10/2020] [Accepted: 09/06/2020] [Indexed: 05/27/2023]
Abstract
Dissolved organic matter (DOM) plays a critical role in determining the quality of wastewater and the safety of drinking water. This is the first review to compare two types of popular DOM monitoring techniques, including absorption spectroscopy and fluorescence excitation-emission matrices (EEMs) coupled with parallel factor analysis (PARAFAC) vs. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), for the applications in wastewater and drinking water treatments. The optical techniques provide a series of indices for tracking the quantity and quality of chromophoric and fluorescent DOM, while FT-ICR-MS is capable of identifying thousands of DOM compounds in wastewater and drinking water at the molecule level. Both types of monitoring techniques are increasingly used in studying DOM in wastewater and drinking water treatments. They provide valuable insights into the variability of DOM composition in wastewater and drinking water. The complexity and diversity of DOM highlight the challenges for effective water treatments. Different effects of various treatment processes on DOM are also assessed, which indicates that the information on DOM composition and its removal is key to optimize the treatment processes. Considering notable progress in advanced treatment processes and novel materials for removing DOM, it is important to continuously utilize these powerful monitoring tools for assessing the responses of different DOM constituents to a series of treatment processes, which can achieve an effective removal of DOM and the quality of treated water.
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Affiliation(s)
- Weixin Shi
- Fujian Provincial Engineering Research Center for High-value Utilization Technology of Plant Resources, College of Environment and Resources, Fuzhou University, Fuzhou, Fujian, China
| | - Wan-E Zhuang
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Jin Hur
- Department of Environment and Energy, Sejong University, Seoul 05006, South Korea
| | - Liyang Yang
- Fujian Provincial Engineering Research Center for High-value Utilization Technology of Plant Resources, College of Environment and Resources, Fuzhou University, Fuzhou, Fujian, China.
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Chen Y, Liu J, Zhang X, Blough NV. Time-Resolved Fluorescence Spectra of Untreated and Sodium Borohydride-Reduced Chromophoric Dissolved Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:12109-12118. [PMID: 32845124 DOI: 10.1021/acs.est.0c03135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Time-resolved fluorescence spectra of chromophoric dissolved organic matter (CDOM) from different sources were acquired using UV (280 and 375 nm) and visible light (440 and 640 nm) excitation to probe the structural basis of the emission properties of CDOM. Emission decays were faster at the blue and red edges, particularly at the red edge, relative to those acquired from 480 to 550 nm. Based on the lifetime distribution and multiexponential analysis of the emission decays recorded at different time resolution, current findings demonstrate that the components recovered based on a superposition model have no defined physical meaning. A substantial increase in steady-state fluorescence intensity and only small changes (<30%) of amplitude-weighted average lifetime caused by sodium borohydride reduction suggest that intramolecular fluorescence quenching occurs mainly through formation of ground state charge-transfer interactions. Short-lived species (lifetime < 100 ps) dominate the emission decays over wavelengths from 400 to 800 nm, particularly under excitation at long wavelengths (440 and 640 nm). Compared to locally excited (LE) states, the contribution of charge-transfer excited (ECT) states and other short-lived species to the steady-state emission is small because of their very rapid nonradiative relaxation. This study suggests that a careful choice of observation wavelength is needed to distinguish LE states from ECT states.
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Affiliation(s)
- Yuan Chen
- Department of Environmental Science, School of Resources and Environmental Science, Wuhan University, Wuhan 430079, P. R. China
| | - Juan Liu
- Department of Environmental Science, School of Resources and Environmental Science, Wuhan University, Wuhan 430079, P. R. China
| | - Xu Zhang
- Department of Environmental Science, School of Resources and Environmental Science, Wuhan University, Wuhan 430079, P. R. China
| | - Neil V Blough
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
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Trubetskaya OE, Richard C, Patsaeva SV, Trubetskoj OA. Evaluation of aliphatic/aromatic compounds and fluorophores in dissolved organic matter of contrasting natural waters by SEC-HPLC with multi-wavelength absorbance and fluorescence detections. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 238:118450. [PMID: 32413721 DOI: 10.1016/j.saa.2020.118450] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 03/05/2020] [Accepted: 05/03/2020] [Indexed: 06/11/2023]
Abstract
The analytical high performance size exclusion liquid chromatography (SEC-HPLC) with multi-wavelength absorbance and fluorescence detections and fluorescence 3D-excitation/emission matrix (EEM) were used for the analysis of average molecular size (MS), molecular size distribution of aliphatic/aromatic compounds and fluorophores in dissolved organic matter (DOM) from Suwannee River (SRDOM) and two Karelian lakes (Vodoprovodnoe Lake - L1DOM and Onego Lake - L2DOM). The average MS of DOM samples varied in the order SRDOM > L1DOM > L2DOM. The absorbance ratios A250/A365 and A210/A254 have been used for the DOM samples characterization. The absorbance ratio A250/A365 provided significant information about average MS of the bulk aquatic DOMs but was not exactly correlated with the results of SEC-HPLC data. The absorbance ratio A210/A254 in combination with SEC was well correlated with the content of DOM aliphatic/aromatic compounds and could be used as an important water quality index to estimate the level of protein-like material in the aquatic DOM. Regardless of the origin (river or lakes), different geographical locations and different average MS of DOM, several similar types of humic-like SEC-separated fluorophores were found within the samples. In all DOM samples the decrease of the fluorophores emission maxima paralleled the decrease of their relative MS. The combination of SEC-HPLC with multi-wavelength fluorescence and absorbance detection and EEM analyses appears very useful for DOM characterization and for tracking of microbial activity resulting from anthropogenic and/or eutrophic impact in aquatic environments.
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Affiliation(s)
- Olga E Trubetskaya
- Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 142290 Pushchino, Moscow region, Russia
| | - Claire Richard
- Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, Equipe Photochimie, BP 10448, F-63000 Clermont-Ferrand, France; CNRS, UMR 6296, ICCF, F-63171 Aubiere, France
| | - Svetlana V Patsaeva
- Faculty of Physics, Lomonosov Moscow State University, Moscow 119992, Russia
| | - Oleg A Trubetskoj
- Institute of Basic Biological Problems, Russian Academy of Sciences, 142290 Pushchino, Moscow region, Russia.
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11
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Wang H, Cheng Z, Sun Z, Zhu N, Yuan H, Lou Z, Chen X. Molecular insight into variations of dissolved organic matters in leachates along China's largest A/O-MBR-NF process to improve the removal efficiency. CHEMOSPHERE 2020; 243:125354. [PMID: 31759208 DOI: 10.1016/j.chemosphere.2019.125354] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 11/04/2019] [Accepted: 11/11/2019] [Indexed: 06/10/2023]
Abstract
Dissolved organic matter (DOM) is a critical component of high-strength organic wastewater, and the study of them from molecular perspective could improve the removal efficiency. Leachate samples were collected from China's largest two stage anaerobic/aerobic membrane bioreactor and nanofiltration (A/O-MBR-NF) process, with the treatment capacity of 5000 t/d, and characterized by electrospray ionization (ESI) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) from molecular perspective. High molecular weight (m/z > 500) compounds with 40-50 carbon atoms and 15-20 double bond equivalence (DBE) were biodegraded into medium molecular weight compounds with 10-20 carbon atoms and ∼10 DBE. Contribution of lipids and unsaturated hydrocarbons compounds in DOM turned into 42.1% and 2.5%, respectively, while contribution of condensed aromatics in DOM dramatically increased to 15.4% in leachates along the A/O-MBR process. Most of DOM was converted into higher polymerization degree and accumulated in concentrated leachate (CL). Sulfur-containing compounds, whose relative peak ratio accounted for 56.4%, were regarded as recalcitrant DOM in CL. Increase of retention time in anaerobic unit for raw leachate might be useful for decomposing the long-chain organic compounds, which could also reduce loadings for the following A/O-MBR process. Well-focus techniques such as sulfur-oxidation bacteria could be introduced into the MBR unit for better removing organo-sulfur compounds. Advanced oxidation processes for CL degradation would be efficiency for the removal of recalcitrant DOM. Thus, leachate could be disposed in a zero-discharge way based on the practical experience of such a typical working treatment process.
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Affiliation(s)
- Hui Wang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Zhaowen Cheng
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Zhiyi Sun
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Nanwen Zhu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Haiping Yuan
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Ziyang Lou
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China; China Institute for Urban Governance, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Xiaoliang Chen
- Shanghai Solid Waste Management Center, Shanghai, 200240, China
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12
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Effect of dissociation constant (pKa) of natural organic matter on photo-generation of reactive oxygen species (ROS). J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2019.112345] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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13
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Sun X, Bai J, Dong D. Influence Factors of Enhanced Photosensitized Degradation of PAHs on Soil Surface Using Humic Acid under UV Irradiation. Polycycl Aromat Compd 2019. [DOI: 10.1080/10406638.2019.1695218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Xuekai Sun
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Jie Bai
- College of Environmental Science, Liaoning University, Shenyang, China
| | - Dianbo Dong
- Liaoning Ecological Environment Protection Science and Technology Center, Shenyang, China
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14
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Schendorf TM, Del Vecchio R, Bianca M, Blough NV. Combined Effects of pH and Borohydride Reduction on Optical Properties of Humic Substances (HS): A Comparison of Optical Models. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:6310-6319. [PMID: 31063364 DOI: 10.1021/acs.est.9b01516] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The combined effects of pH and borohydride reduction on the optical properties of a series of humic substances and a lignin model were examined to probe the molecular moieties and interactions that give rise to the observed optical properties of these materials. Increasing the pH from 2 to 12 produced significantly enhanced absorption across the spectra of all samples, with distinct spectral responses observed over pH ranges attributable to the deprotonation of carboxylic acids and phenols. Borohydride reduction substantially attenuated the broadband absorption enhancements with pH, clearly indicating that the loss of absorption due to ketone/aldehyde reduction is coupled with the pH-dependent increase in absorption due to deprotonation of carboxylic acids and phenols. These results cannot be easily explained by a superposition of the spectra of independently absorbing chromophores (superposition model) but are readily interpretable within a charge transfer (CT) model. Changes of fluorescence emission with pH for both untreated and borohydride reduced samples suggest that a pH-dependent structural reorganization of the HS may also be influencing the fluorescence emission. Independent of optical model, these results demonstrate that chemical tests targeted to specific moieties can identify distinct structural differences among HS sources as well as provide insight into the molecular moieties and interactions that produce the observed optical and photochemical properties.
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15
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Sazawa K, Yoshida H, Okusu K, Hata N, Kuramitz H. Effects of forest fire on the properties of soil and humic substances extracted from forest soil in Gunma, Japan. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:30325-30338. [PMID: 30159838 DOI: 10.1007/s11356-018-3011-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 08/20/2018] [Indexed: 06/08/2023]
Abstract
Increases in global wildfires and fire severity are expected to result from global warming. Severe wildfires not only burn surface vegetation but also affect forest soil. Humic substances play key roles in the transport of nutrients and the carbon cycle in terrestrial ecosystems. In this study, we evaluated the effects of forest fires on the chemical properties of fulvic acid (FA) and humic acid (HA) extracted from non-burned and burned forest soils in Gunma, Japan. The differential thermal analysis of FA indicated that the intensity of exothermic reaction peak at 400 °C was 2-fold higher than that from non-burned soil. Based on pyrolysis-gas chromatography-mass spectrometry analysis with tetramethyl ammonium hydroxide, the amount of pyrolysate compounds in FA from burnt soil was significantly lower than that in FA from non-burnt soil. Therefore, we can conclude that the forest fire caused the significant change in the properties of FA such as increasing the aromaticity and refractory. In addition, the concentration of dissolved organic carbon with low molecular weight in surface soil increased after forest fire. This study suggests that the denaturation of soil organic matter by wildfire can affect the carbon cycle in terrestrial ecosystems.
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Affiliation(s)
- Kazuto Sazawa
- Center for Far Eastern Studies, University of Toyama, Gofuku 3190, Toyama, 930-8555, Japan
- Department of Environmental Biology and Chemistry, Graduate School of Science and Engineering for Research, University of Toyama, Gofuku 3190, Toyama, 930-8555, Japan
| | - Hironori Yoshida
- Center for Far Eastern Studies, University of Toyama, Gofuku 3190, Toyama, 930-8555, Japan
| | - Katsuya Okusu
- Center for Far Eastern Studies, University of Toyama, Gofuku 3190, Toyama, 930-8555, Japan
| | - Noriko Hata
- Center for Far Eastern Studies, University of Toyama, Gofuku 3190, Toyama, 930-8555, Japan
| | - Hideki Kuramitz
- Center for Far Eastern Studies, University of Toyama, Gofuku 3190, Toyama, 930-8555, Japan.
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16
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Zhou Z, Chen B, Qu X, Fu H, Zhu D. Dissolved Black Carbon as an Efficient Sensitizer in the Photochemical Transformation of 17β-Estradiol in Aqueous Solution. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:10391-10399. [PMID: 30130961 DOI: 10.1021/acs.est.8b01928] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Dissolved black carbon (DBC) is an important component of the dissolved organic matter (DOM) pool. Nonetheless, little is known about its role in the photochemical processes of organic contaminants. This study investigated the effect of DBC on the phototransformation of 17β-estradiol in aqueous solutions under simulated sunlight. Four well-studied dissolved humic substances (DHS) were included as comparisons. DBC acted as a very effective sensitizer to facilitate the phototransformation of 17β-estradiol. The apparent quantum yield for 17β-estradiol phototransformation mediated by DBC was approximately six times higher than that by DHS at the same carbon concentration. Quenching experiments suggested that direct reaction with triplet-excited state DBC (3DBC*) was the predominant pathway of 17β-estradiol phototransformation. The higher mediation efficiency of DBC than DHS is likely due to the higher contents of aromatic groups and smaller molecular sizes, which facilitated the generation of 3DBC*. The apparent quantum yield of triplet-excited states production for DBC was 4-8 times higher than that for DHS. The results suggest that 3DBC* may have a considerable contribution to the overall photoreactivity of triplet-excited state DOM in aquatic systems. Our findings also imply that DBC can play an important role in the phototransformation of organic contaminants in the environments.
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Affiliation(s)
- Zhicheng Zhou
- State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment , Nanjing University , Nanjing , Jiangsu 210046 , China
| | - Beining Chen
- State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment , Nanjing University , Nanjing , Jiangsu 210046 , China
| | - Xiaolei Qu
- State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment , Nanjing University , Nanjing , Jiangsu 210046 , China
| | - Heyun Fu
- State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment , Nanjing University , Nanjing , Jiangsu 210046 , China
| | - Dongqiang Zhu
- School of Urban and Environmental Sciences , Peking University , Beijing 100871 , China
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17
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Yang Y, Li J, Shi H, Zhai L, Wang X, Gao S. Influence of natural organic matter on horseradish peroxidase-mediated removal of 17α-ethinylestradiol: Role of molecular weight. JOURNAL OF HAZARDOUS MATERIALS 2018; 356:9-16. [PMID: 29803032 DOI: 10.1016/j.jhazmat.2018.05.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 05/14/2018] [Accepted: 05/15/2018] [Indexed: 06/08/2023]
Abstract
Ubiquitous natural organic matter (NOM) plays a crucial role in the peroxidase-mediated transformation of phenolic pollutants in aquatic environment. As a poorly defined polydispersed mixture of assorted organic substances with wide molecular weight (MW) distribution, NOM has far prevented researchers from finding out the primarily responsible components for the specific effect. In this work, MW fractionated NOMs (Mf-NOMs) were used to investigate their roles on horseradish peroxidase (HRP)-mediated transformation of 17α-ethinylestradiol (EE2). The removal rate of EE2 was restrained in the presence of pristine or Mf-NOMs, and the inhibitory mechanism was MW-dependent. Low Mf-NOMs restrained the enzymatic reaction by acting as competitive substrates, while high Mf-NOMs retained freely dissolved EE2 which reduced its availability for enzymatic reaction. The contribution of these two processes to the inhibition induced by pristine NOM was further quantified and found to be relevant to the reaction conditions, especially EE2 concentration. The findings of this work reveal more complex influences of NOM on the enzymatic reaction than ever demonstrated, which aids in understanding the fate of EE2 and other congener contaminants in natural and municipal water.
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Affiliation(s)
- Yun Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China
| | - Jianhua Li
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China
| | - Huanhuan Shi
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China
| | - Li Zhai
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China
| | - Xing Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China
| | - Shixiang Gao
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China.
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18
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Trubetskoj OA, Richard C, Voyard G, Marchenkov VV, Trubetskaya OE. Molecular Size Distribution of Fluorophores in Aquatic Natural Organic Matter: Application of HPSEC with Multi-Wavelength Absorption and Fluorescence Detection Following LPSEC-PAGE Fractionation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:5287-5295. [PMID: 29624400 DOI: 10.1021/acs.est.7b03924] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Analytical high performance size exclusion liquid chromatography (HPSEC) with multiwavelength absorbance and fluorescence detections was used for the analysis of molecular size distribution and optical properties of dissolved natural organic matter. Experiments were conducted on Suwannee River organic matter (SRNOM) and its fractions A, B, C+D preliminary obtained by combination of preparative low pressure size exclusion chromatography and polyacrylamide gel electrophoresis (LPSEC-PAGE) and purified by dialysis on membrane with nominal cutoff 10 kDa, the fractions molecular size varied in order A > B > C + D > 10 kDa. The multistep fractionation of SRNOM enabled the size-separation of at least five types of humic-like fluorophores within NOM showing emission maxima at 465, 450, 435, 420, and 405 nm. The decrease of the humic-like emission maxima paralleled the decrease of the nominal molecular size of fluorescent SRNOM. The protein-like fluorescence was split into tyrosine-like and tryptophan-like fluorophores and only detected in fractions A and B. This work provides new data on the optical properties of size-fractionated NOM, which consistent with the formation of supramolecular NOM assemblies, likely controlled by association of low-molecular size components. It is clearly observed for the high molecular size fraction A, containing free amino acids or short peptides. The combination of several different fractionation procedures is very useful for obtaining less complex NOM compounds and understanding the NOM function in the environment.
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Affiliation(s)
- Oleg A Trubetskoj
- Institute of Basic Biological Problems , Russian Academy of Sciences , 142290 , Pushchino , Moscow Region Russia
| | - Claire Richard
- Clermont Université, Université Blaise Pascal , Institut de Chimie de Clermont-Ferrand, Equipe Photochimie , BP 10448, F-63000 Clermont-Ferrand , France
- CNRS , UMR 6296, ICCF , F-63171 Aubiere , France
| | - Guillaume Voyard
- Clermont Université, Université Blaise Pascal , Institut de Chimie de Clermont-Ferrand, Equipe Photochimie , BP 10448, F-63000 Clermont-Ferrand , France
- CNRS , UMR 6296, ICCF , F-63171 Aubiere , France
| | - Victor V Marchenkov
- Institute of Protein Research , Russian Academy of Sciences , 142290 Pushchino , Moscow Region Russia
| | - Olga E Trubetskaya
- Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry , Russian Academy of Sciences , 142290 , Pushchino , Moscow Region Russia
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19
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Ren D, Huang B, Xiong D, He H, Meng X, Pan X. Photodegradation of 17α-ethynylestradiol in dissolved humic substances solution: Kinetics, mechanism and estrogenicity variation. J Environ Sci (China) 2017; 54:196-205. [PMID: 28391929 DOI: 10.1016/j.jes.2016.03.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/25/2016] [Accepted: 03/01/2016] [Indexed: 06/07/2023]
Abstract
17α-Ethynylestradiol (EE2) in natural waters may cause adverse effects on organisms due to its high estrogenic potency. Laboratory studies were performed to study the effects of a local humic acid (LHA), fulvic acid (LFA) and Aldrich humic acid (AHA) on the photochemical behavior and estrogenic potency of EE2. Here photolytic experiments demonstrated that pure aqueous EE2 could undergo direct and self-sensitized photodegradation at a global rate of 0.0068hr-1. Photodegradation rate of EE2 in 5.0mg/L dissolved humic substances (DHS) was determined to be 0.0274, 0.0296 and 0.0254hr-1 for LHA, LFA and AHA, respectively. Reactive oxygen species (ROS) and triplet dissolved humic substances (3DHS*) scavenging experiments indicated that the promotion effect of DHS on EE2 photodegradation was mainly aroused by the reactions of HO (35%-50%), 1O2 (<10%) and 3DHS* (22%-34%). However, the photodegradation of EE2 could also be inhibited when DHS exceeded the threshold of 10mg/L. Three hydroxylation products of EE2 were identified using GC-MS and their formation pathways were also proposed. In vitro estrogenicity tests showed that EE2 was transformed into chemicals without estrogenic potency. These findings could extend our knowledge on the photochemical behaviors of steroid estrogens in sunlit natural waters.
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Affiliation(s)
- Dong Ren
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China.
| | - Bin Huang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China.
| | - Dan Xiong
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Huan He
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Xiangqi Meng
- 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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20
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Uyguner-Demirel CS, Birben NC, Bekbolet M. Elucidation of background organic matter matrix effect on photocatalytic treatment of contaminants using TiO 2 : A review. Catal Today 2017. [DOI: 10.1016/j.cattod.2016.12.030] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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21
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Shimabuku KK, Kennedy AM, Mulhern RE, Summers RS. Evaluating Activated Carbon Adsorption of Dissolved Organic Matter and Micropollutants Using Fluorescence Spectroscopy. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:2676-2684. [PMID: 28117982 DOI: 10.1021/acs.est.6b04911] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Dissolved organic matter (DOM) negatively impacts granular activated carbon (GAC) adsorption of micropollutants and is a disinfection byproduct precursor. DOM from surface waters, wastewater effluent, and 1 kDa size fractions were adsorbed by GAC and characterized using fluorescence spectroscopy, UV-absorption, and size exclusion chromatography (SEC). Fluorescing DOM was preferentially adsorbed relative to UV-absorbing DOM. Humic-like fluorescence (peaks A and C) was selectively adsorbed relative to polyphenol-like fluorescence (peaks T and B) potentially due to size exclusion effects. In the surface waters and size fractions, peak C was preferentially removed relative to peak A, whereas the reverse was found in wastewater effluent, indicating that humic-like fluorescence is associated with different compounds depending on DOM source. Based on specific UV-absorption (SUVA), aromatic DOM was preferentially adsorbed. The fluorescence index (FI), if interpreted as an indicator of aromaticity, indicated the opposite but exhibited a strong relationship with average molecular weight, suggesting that FI might be a better indicator of DOM size than aromaticity. The influence of DOM intermolecular interactions on adsorption were minimal based on SEC analysis. Fluorescence parameters captured the impact of DOM size on the fouling of 2-methylisoborneol and warfarin adsorption and correlated with direct competition and pore blockage indicators.
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Affiliation(s)
- Kyle K Shimabuku
- Department of Civil, Environmental and Architectural Engineering, 428 UCB, University of Colorado, Boulder , Boulder, Colorado 80309, United States
| | - Anthony M Kennedy
- Department of Civil, Environmental and Architectural Engineering, 428 UCB, University of Colorado, Boulder , Boulder, Colorado 80309, United States
- Technical Service Center, US Bureau of Reclamation , Denver Federal Center Building 67, Denver, Colorado 80225, United States
| | - Riley E Mulhern
- Department of Civil, Environmental and Architectural Engineering, 428 UCB, University of Colorado, Boulder , Boulder, Colorado 80309, United States
| | - R Scott Summers
- Department of Civil, Environmental and Architectural Engineering, 428 UCB, University of Colorado, Boulder , Boulder, Colorado 80309, United States
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22
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Maizel AC, Remucal CK. Molecular Composition and Photochemical Reactivity of Size-Fractionated Dissolved Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:2113-2123. [PMID: 28121132 PMCID: PMC5889133 DOI: 10.1021/acs.est.6b05140] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The photochemical production of reactive species, such as triplet dissolved organic matter (3DOM) and singlet oxygen (1O2), contributes to the degradation of aquatic contaminants and is related to an array of DOM structural characteristics, notably molecular weight. In order to relate DOM molecular weight, optical properties, and reactive species production, Suwannee River (SRFA) and Pony Lake fulvic acid (PLFA) isolates are fractionated by sequential ultrafiltration, and the resultant fractions are evaluated in terms of molecular composition and photochemical reactivity. UV-visible measurements of aromaticity increase with molecular weight in both fulvic acids, while PLFA molecular weight fractions are shown to be structurally similar by Fourier-transform ion cyclotron resonance mass spectrometry. In addition, Bray-Curtis dissimilarity analysis of formulas identified in the isolates and their size fractions reveal that SRFA and PLFA have distinct molecular compositions. Quantum yields of 3DOM, measured by electron and energy transfer probes, and 1O2 decreased with molecular weight. Decreasing [3DOM]ss with molecular weight is shown to derive from elevated quenching in high molecular weight fractions, rather than increased 3DOM formation. This work has implications for the photochemistry of waters undergoing natural or engineered treatment processes that alter DOM molecular weight, such as photooxidation and biological degradation.
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Affiliation(s)
- Andrew C. Maizel
- Department of Civil and Environmental Engineering, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States
| | - Christina K. Remucal
- Department of Civil and Environmental Engineering, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States
- Environmental Chemistry and Technology Program, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States
- Corresponding Author: ; telephone: (608) 262-1820; fax: (608) 262-0454; Twitter: @remucal
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23
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Zhang D, Yin Y, Li Y, Cai Y, Liu J. Critical role of natural organic matter in photodegradation of methylmercury in water: Molecular weight and interactive effects with other environmental factors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 578:535-541. [PMID: 27839761 DOI: 10.1016/j.scitotenv.2016.10.222] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 10/29/2016] [Accepted: 10/30/2016] [Indexed: 06/06/2023]
Abstract
Photodegradation is the main depletion pathway of methylmercury (MeHg) in surface water. However, the underlying mechanism of MeHg photodegradation is still not well understood. In this study, the critical role of natural organic matter (NOM) from Suwannee River natural organic matter of the International Humic Substance Society, especially its molecular weight, and the impacts of other related environmental factors in MeHg photodegradation were investigated. We observed that MeHg cannot photo-degrade in de-ionized water, excluding the direct photodegradation of MeHg. While either NOM or Fe3+ alone induced MeHg photodegradation, co-existing NOM significantly inhibited the Fe3+-induced degradation, highlighting the critical and complex role of NOM in MeHg photodegradation. Additionally, MeHg exhibited different photodegradation rates in the presence of molecular weight fractionated natural organic matter (Mf-NOM). More importantly, high concentration of NOM caused light attenuation significantly inhibited the photodegradation of MeHg, which was more significant for high molecular weight Mf-NOM. In the presence of Mf-NOM, MeHg photodegradation was also affected by light quality, pH and co-existing Cl- and NO3-. The study is helpful for a better understanding of the critical role of NOM and other environmental factors on MeHg photodegradation in surface water.
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Affiliation(s)
- Dan Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yongguang Yin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yanbin Li
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, China
| | - Yong Cai
- Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Jingfu Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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24
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Angthararuk D, Harir M, Schmitt-Kopplin P, Sutthivaiyakit S, Kettrup A, Sutthivaiyakit P. Degradation products of profenofos as identified by high-field FTICR mass spectrometry: Isotopic fine structure approach. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART. B, PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES 2017; 52:10-22. [PMID: 27628767 DOI: 10.1080/03601234.2016.1224696] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This study was performed to identify the degradation products of profenofos "a phenyl organothiophosphate insecticide" in raw water (RW) collected from the entry point of Metropolitan Water Works Authority "Bangkaen, Thailand" and ultrapure water (UPW) with and without TiO2 under simulated sunlight irradiation. Degradation of profenofos was followed with ultrahigh performance liquid chromatography (UHPLC) and follows pseudo first-order kinetic. Accordingly, high-field FTICR mass spectrometry coupled to an electrospray ionization source was used to reveal the degradation routes of profenofos and the isotopic fine structures (IFS) elucidations to approve the chemical structures of its degradation products. More degradation products were detected in UPW as compared to RW. Consequently, two main degradation pathways namely (i) interactive replacements of bromine and hydrogen by hydroxyl functional groups and (ii) rupture of PO, PS, CBr and CCl bonds were observed. None interactive replacement of chlorine by hydroxyl functional group was detected. Accordingly, mechanistical pathways of the main degradation products were established.
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Affiliation(s)
- Dusit Angthararuk
- a Department of Chemistry and Center of Excellence for Innovation in Chemistry , Faculty of Science, Kasetsart University , Bangkok , Thailand
- b Department of Chemistry , Faculty of Science and Technology, Suan Dusit Rajabhat University , Bangkok , Thailand
| | - Mourad Harir
- c Research Unit Analytical BioGeoChemistry , Helmholtz Zentrum München , Neuherberg , Germany
- d Chair Analyt Food Chemistry, Technische Universität München , Freising Weihenstephan , Germany
| | - Philippe Schmitt-Kopplin
- c Research Unit Analytical BioGeoChemistry , Helmholtz Zentrum München , Neuherberg , Germany
- d Chair Analyt Food Chemistry, Technische Universität München , Freising Weihenstephan , Germany
| | - Somyote Sutthivaiyakit
- e Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science , Ramkhamhaeng University , Bangkok , Thailand
| | | | - Pakawadee Sutthivaiyakit
- a Department of Chemistry and Center of Excellence for Innovation in Chemistry , Faculty of Science, Kasetsart University , Bangkok , Thailand
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Bianco A, Fabbri D, Minella M, Brigante M, Mailhot G, Maurino V, Minero C, Vione D. Photochemical transformation of benzotriazole, relevant to sunlit surface waters: Assessing the possible role of triplet-sensitised processes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 566-567:712-721. [PMID: 27239714 DOI: 10.1016/j.scitotenv.2016.05.119] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 04/22/2016] [Accepted: 05/17/2016] [Indexed: 06/05/2023]
Affiliation(s)
- Angelica Bianco
- Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand, France
| | - Debora Fabbri
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Turin, Italy(1)
| | - Marco Minella
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Turin, Italy(1)
| | - Marcello Brigante
- Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand, France; CNRS, UMR 6296, ICCF, BP 80026, F-63177 Aubière, France.
| | - Gilles Mailhot
- Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand, France; CNRS, UMR 6296, ICCF, BP 80026, F-63177 Aubière, France
| | - Valter Maurino
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Turin, Italy(1)
| | - Claudio Minero
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Turin, Italy(1)
| | - Davide Vione
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Turin, Italy(1); Università degli Studi di Torino, Centro Interdipartimentale NatRisk, Via L. Da Vinci 44, 10095 Grugliasco (TO), Italy(2).
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McKay G, Couch KD, Mezyk SP, Rosario-Ortiz FL. Investigation of the Coupled Effects of Molecular Weight and Charge-Transfer Interactions on the Optical and Photochemical Properties of Dissolved Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8093-102. [PMID: 27377760 PMCID: PMC8903045 DOI: 10.1021/acs.est.6b02109] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We studied the formation of photochemically produced reactive intermediates (RI) from dissolved organic matter (DOM). Specifically, we focused on the effects of variable molecular weight and chemical reduction on the optical properties of DOM (absorbance and fluorescence) and the formation of singlet oxygen ((1)O2), DOM triplet excited states ((3)DOM*), and the hydroxyl radical ((•)OH). The data are largely evaluated in terms of a charge-transfer (CT) model, but deficiencies in the model to explain the data are pointed out when evident. A total of two sets of samples were studied that were subjected to different treatments; the first set included secondary-treated wastewaters and a wastewater-impacted stream, and the second was a DOM isolate. Treatments included size fractionation and chemical reduction using sodium borohydride. Taken as a whole, the results demonstrate that decreasing molecular weight and borohydride reduction work in opposition regarding quantum efficiencies for (1)O2 and (3)DOM* production but in concert for fluorescence and (•)OH production. The optical and photochemical data provide evidence for a limited role of CT interactions occurring in lower-molecular-weight DOM molecules. In addition, the data suggest that the observed optical and photochemical properties of DOM are a result of multiple populations of chromophores and that their relative contribution is changed by molecular-weight fractionation and borohydride reduction.
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Affiliation(s)
- Garrett McKay
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, Colorado 80309, United States
- Corresponding Authors: G.M.: . F.L.R.-O.:
| | - Kylie D. Couch
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, Colorado 80309, United States
- Department of Chemistry and Biochemistry, California State University, Long Beach, California 90840, United States
| | - Stephen P. Mezyk
- Department of Chemistry and Biochemistry, California State University, Long Beach, California 90840, United States
| | - Fernando L. Rosario-Ortiz
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, Colorado 80309, United States
- Corresponding Authors: G.M.: . F.L.R.-O.:
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Yasadi K, Pinheiro JP, Zielińska K, Town RM, van Leeuwen HP. Partitioning of humic acids between aqueous solution and hydrogel. 3. Microelectrodic dynamic speciation analysis of free and bound humic metal complexes in the gel phase. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:1737-1745. [PMID: 25580682 DOI: 10.1021/la504885v] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The hydrogel/water partitioning of the various species in the cadmium(II)/soil humic acid (HA) system is studied for two types of gel, using in situ microelectrodic voltammetry. Under the conditions of this work, with HA particles of ca. 25 and 125 nm radius, the CdHA complex is shown to be close to nonlabile toward a 12.5 μm radius microelectrode. This implies that its kinetic contribution to Cd(2+) reduction at the medium/microelectrode interface is practically negligible. The polyacrylamide (PAAm) gels equilibrate with the aqueous medium under significant sorption of HA at the gel backbone/gel medium interface, which in turn leads to induced sorption of Cd(II) in the form of immobilized gel-bound CdHA. The rather high total Cd content of the PAAm gel suggests that the binding of Cd(2+) by the hydrophobically gel-bound HA is stronger than that for dispersed HA particles. Still, the intraparticulate speciation of Cd(II) over Cd(2+) and CdHA corresponds to an intrinsic stability constant similar to that for simple monocarboxylate ligands such as acetate. Alginate gels are negatively charged, and their free [Cd(aq)(2+)] is higher than that in the medium by the corresponding Donnan coefficient. On top of that, Cd(2+) is specifically sorbed by the gel backbone/gel medium interface to reach accumulation factors as high as a few tens. HA and CdHA accumulate in the outer 20 μm film of gel at the gel/water interface of both gels, but they do not penetrate into the bulk of the alginate gel. Overall, the gel/water interface dictates drastic changes in the speciation of Cd/HA as compared to the aqueous medium, with distinct features for each individual type of gel. The results have broad significance, for example, for predictions of reactivity and bioavailability of metal species which inherently involve partitioning and diffusion into diverse gel layers such as biointerfacial cell walls, biofilm matrices, and mucous membranes.
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Affiliation(s)
- Kamuran Yasadi
- Laboratory of Physical Chemistry and Colloid Science, Wageningen University , Dreijenplein 6, 6703 HB Wageningen, The Netherlands
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28
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Kihara Y, Sazawa K, Kuramitz H, Kurasaki M, Saito T, Hosokawa T, Syawal MS, Wulandari L, Tanaka S. Effects of peat fires on the characteristics of humic acid extracted from peat soil in Central Kalimantan, Indonesia. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:2384-2395. [PMID: 24781330 DOI: 10.1007/s11356-014-2929-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 04/15/2014] [Indexed: 06/03/2023]
Abstract
When peat forest fires happen, it leads to burn soil and also humic acids as a dominant organic matter contained in peat soil as well as the forest. The structure and properties of humic acids vary depending on their origin and environment, therefore the transformation of humic acid is also diverse. The impacts of the peat fires on peat soil from Central Kalimantan, Indonesia were investigated through the characterization of humic acids, extracted from soil in burnt and unburnt sites. The characterization of humic acids was performed by elemental composition, functional groups, molecular weight by HPSEC, pyrolysate compounds by pyrolysis-GC/MS, fluorescence spectrum by 3DEEM spectrofluorometer, and thermogravimetry. The elemental composition of each humic substance indicated that the value of H/C and O/C of humic acids from burnt sites were lower than that from unburnt sites. The molecular weight of humic acids from burnt sites was also lower than that from unburnt sites. Pyrolysate compounds of humic acids from unburnt sites differed from those of humic acids from burnt soil. The heating experiment showed that burning process caused the significant change in the properties of humic acids such as increasing the aromaticity and decreasing the molecular weight.
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29
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Zielińska K, Town RM, Yasadi K, van Leeuwen HP. Partitioning of humic acids between aqueous solution and hydrogel. 2. Impact of physicochemical conditions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 31:283-291. [PMID: 25479141 DOI: 10.1021/la504393r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The effects of the physicochemical features of aqueous medium on the mode of partitioning of humic acids (HAs) into a model biomimetic gel (alginate) and a synthetic polyacrylamide gel (PAAm) were explored. Experiments were performed under conditions of different pH and ionic strength as well as in the presence or absence of complexing divalent metal ions. The amount of HA penetrating the gel phase was determined by measuring its natural fluorescence by confocal laser scanning microscopy. In both gel types, the accumulation of HA was spatially heterogeneous, with a much higher concentration located within a thin film at the gel surface. The thickness of the surface film (ca. 15 μm) was similar for both types of gel and practically independent of pH, ionic strength, and the presence of complexing divalent metal ions. The extent of HA accumulation was found to be dependent on the composition of the medium and on the type of gel. Significantly more HA was accumulated in PAAm gel as compared to that in alginate gel. In general, more HA was accumulated at lower background salt concentration levels. The distribution of different types of HA species in the gel body was linked to their behavior in the medium and the differences in physicochemical conditions inside the two phases.
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Affiliation(s)
- Katarzyna Zielińska
- Laboratory of Physical Chemistry and Colloid Science, Wageningen University , Dreijenplein 6, 6703 HB Wageningen, The Netherlands
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30
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Yin Y, Shen M, Zhou X, Yu S, Chao J, Liu J, Jiang G. Photoreduction and stabilization capability of molecular weight fractionated natural organic matter in transformation of silver ion to metallic nanoparticle. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:9366-9373. [PMID: 25050868 DOI: 10.1021/es502025e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Photoinduced reduction of silver ion (Ag(+)) to silver nanoparticles (AgNPs) by dissolved organic matter (DOM) plays a crucial role in the transformation and transport of engineered AgNPs and Ag(+) in aquatic environments. DOM is a mixture of natural polymers with wide molecular weight (MW) distribution, and the roles of specific components of DOM in the photoreduction of Ag(+) to AgNPs are still not understood. In this study, MW fractionated natural organic matter (Mf-NOM) were investigated for their roles on the photoreduction process and stabilization of the formed AgNPs. This photoinduced reduction process depends highly on pH, concentration of Ag(+) and NOM, light quality, and the MW of Mf-NOM. Monochromatic radiation and light attenuation correction suggested that the difference of Mf-NOM on reduction was mainly ascribed to the differential light attenuation of Mf-NOM rather than the "real" reductive ability. More importantly, compared with low MW fractions, the high MW Mf-NOMs exhibit drastically higher capability in stabilizing the photosynthesized AgNPs against Ca(2+)-induced aggregation. This finding is important for a better understanding of the differential roles of Mf-NOM in the transformation and transport of Ag(+) and engineered AgNPs in DOM-rich surface water.
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Affiliation(s)
- Yongguang Yin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China
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31
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Korak JA, Rosario-Ortiz FL, Summers RS. Fluorescence Characterization of Humic Substance Coagulation: Application of New Tools to an Old Process. ACTA ACUST UNITED AC 2014. [DOI: 10.1021/bk-2014-1160.ch014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Affiliation(s)
- Julie A. Korak
- Department of Civil, Environmental and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado 80309, U.S.A
| | - Fernando L. Rosario-Ortiz
- Department of Civil, Environmental and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado 80309, U.S.A
| | - R. Scott Summers
- Department of Civil, Environmental and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado 80309, U.S.A
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32
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Vione D, Minella M, Maurino V, Minero C. Indirect photochemistry in sunlit surface waters: photoinduced production of reactive transient species. Chemistry 2014; 20:10590-606. [PMID: 24888627 DOI: 10.1002/chem.201400413] [Citation(s) in RCA: 261] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Indexed: 11/09/2022]
Abstract
This paper gives an overview of the main reactive transient species that are produced in surface waters by sunlight illumination of photoactive molecules (photosensitizers), such as nitrate, nitrite, and chromophoric dissolved organic matter (CDOM). The main transients (˙OH, CO3(-˙) , (1)O2, and CDOM triplet states) are involved in the indirect phototransformation of a very wide range of persistent organic pollutants in surface waters.
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Affiliation(s)
- Davide Vione
- Department of Chemistry, University of Torino, Via Pietro Giuria 5, 10125 Torino (Italy), Fax: (+39) 011-6705242; NatRisk Inter-Department Centre, University of Torino, Via Leonardo Da Vinci 44, 10095 Grugliasco (TO) (Italy).
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33
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Timko SA, Romera-Castillo C, Jaffé R, Cooper WJ. Photo-reactivity of natural dissolved organic matter from fresh to marine waters in the Florida Everglades, USA. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:866-78. [PMID: 24549208 DOI: 10.1039/c3em00591g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Natural dissolved organic matter (DOM) is the major absorber of sunlight in most natural waters and a critical component of carbon cycling in aquatic systems. The combined effect of light absorbance properties and related photo-production of reactive species are essential in determining the reactivity of DOM. Optical properties and in particular excitation-emission matrix fluorescence spectroscopy combined with parallel factor analysis (EEM-PARAFAC) have been used increasingly to track sources and fate of DOM. Here we describe studies conducted in water from two estuarine systems in the Florida Everglades, with a salinity gradient of 2 to 37 and dissolved organic carbon concentrations from 19.3 to 5.74 mg C L(-1), aimed at assessing how the quantity and quality of DOM is coupled to the formation rates and steady-state concentrations of reactive species including singlet oxygen, hydroxyl radical, and the triplet excited state of DOM. These species were related to optical properties and PARAFAC components of the DOM. The formation rate and steady-state concentration of the carbonate radical was calculated in all samples. The data suggests that formation rates, particularly for singlet oxygen and hydroxyl radicals, are strongly coupled to the abundance of terrestrial humic-like substances. A decrease in singlet oxygen, hydroxyl radical, and carbonate radical formation rates and steady-state concentration along the estuarine salinity gradient was observed as the relative concentration of terrestrial humic-like DOM decreased due to mixing with microbial humic-like and protein-like DOM components, while the formation rate of triplet excited-state DOM did not change. Fluorescent DOM was also found to be more tightly coupled to reactive species generation than chromophoric DOM.
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Affiliation(s)
- Stephen A Timko
- Department of Civil and Environmental Engineering, University of California, Irvine, CA 92697-2175, USA.
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34
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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: 150] [Impact Index Per Article: 15.0] [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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35
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Remucal CK. The role of indirect photochemical degradation in the environmental fate of pesticides: a review. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:628-53. [PMID: 24419250 DOI: 10.1039/c3em00549f] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Photochemical degradation contributes to the environmental fate of many pesticides in surface waters. A better understanding of the role of direct and indirect photochemical degradation of pesticides is necessary in order to predict their environmental fate and persistence. This review includes all major pesticide classes and focuses on the importance of dissolved organic matter (DOM) as a sensitizer in indirect photodegradation within aquatic systems. Photochemical studies conducted under environmentally relevant conditions (i.e., aqueous solutions with irradiation wavelengths >290 nm) are included. Comparisons are made between observed photodegradation rates in pure or buffered water and in water containing DOM to assess the extent of pesticide susceptibility to DOM-sensitized indirect photolysis. When data is available, the role of specific reactive species in indirect photodegradation is described. While it is possible to assess the relative importance of direct and indirect photodegradation on a pesticide-by-pesticide basis in many cases, it is often difficult to make generalizations based on compound class. Knowledge gaps and inconstancies in the current body of literature are discussed and areas that require additional research are described.
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Affiliation(s)
- Christina K Remucal
- University of Wisconsin-Madison, Department of Civil and Environmental Engineering, 660 N. Park St., Madison, WI, USA.
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36
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Zielińska K, Town RM, Yasadi K, van Leeuwen HP. Partitioning of humic acids between aqueous solution and hydrogel: concentration profiling of humic acids in hydrogel phases. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:2084-2092. [PMID: 24512499 DOI: 10.1021/la4050094] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The partitioning of the natural polyelectrolyte humic acid (HA) from an aqueous dispersion into a model biomimetic gel (alginate) and a synthetic polyacrylamide gel (PAAm) is explored. In both gels, the spatial distribution of HA in the gel body, as measured by confocal laser scanning microscopy, is markedly nonhomogeneous. A striking feature is the enhanced accumulation of HA in a thin film of thickness ca. 15 μm at the surface of the gel body, resulting in average local concentrations that are, for PAAm and alginate respectively, a factor of 10 and 4 greater than that in the bulk solution. The time dependence of accumulation in the surface film is predominantly controlled by the diffusive supply of HA from the aqueous medium, with a time constant on the order of 10(3) s for both gels. The concentration of HA within the bulk gel body differs significantly from that in the bulk aqueous medium: substantially higher for PAAm but much lower for alginate. The results are significant for understanding the nature and rate of sink/source functioning at permeable phases in contact with aqueous media, e.g., biofilms and gel-like layers at biological interfaces or employed in chemical speciation sensors.
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Affiliation(s)
- Katarzyna Zielińska
- Laboratory of Physical Chemistry and Colloid Science, Wageningen University , Dreijenplein 6, 6703 HB Wageningen, The Netherlands
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37
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Relation between Optical Properties and Formation of Reactive Intermediates from Different Size Fractions of Organic Matter. ACS SYMPOSIUM SERIES 2014. [DOI: 10.1021/bk-2014-1160.ch008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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38
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Zeng T, Arnold WA. Pesticide photolysis in prairie potholes: probing photosensitized processes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:6735-45. [PMID: 23116462 DOI: 10.1021/es3030808] [Citation(s) in RCA: 165] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Prairie pothole lakes (PPLs) are glacially derived, ecologically important water bodies found in central North America and represent a unique setting in which extensive agriculture occurs within wetland ecosystems. In the Prairie Pothole Region (PPR), elevated pesticide use and increasing hydrologic connectivity have raised concerns about the impact of nonpoint source agricultural pollution on the water quality of PPLs and downstream aquatic systems. Despite containing high dissolved organic matter (DOM) levels, the photoreactivity of the PPL water and the photochemical fate of pesticides entering PPLs are largely unknown. In this study, the photodegradation of sixteen pesticides was investigated in PPL waters sampled from North Dakota, under simulated and natural sunlight. Enhanced pesticide removal rates in the irradiated PPL water relative to the control buffer pointed to the importance of indirect photolysis pathways involving photochemically produced reactive intermediates (PPRIs). The steady-state concentrations of carbonate radical, hydroxyl radical, singlet oxygen, and triplet-excited state DOM were measured and second-order rate constants for reactions of pesticides with these PPRIs were calculated. Results from this study underscore the role of DOM as photosensitizer in limiting the persistence of pesticides in prairie wetlands through photochemical reactions.
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Affiliation(s)
- Teng Zeng
- Department of Civil Engineering, University of Minnesota, 500 Pillsbury Drive Southeast, Minneapolis, Minnesota 55455, United States
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39
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Wang Y, Hayatsu M, Fujii T. Extraction of bacterial RNA from soil: challenges and solutions. Microbes Environ 2012; 27:111-21. [PMID: 22791042 PMCID: PMC4036013 DOI: 10.1264/jsme2.me11304] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Detection of bacterial gene expression in soil emerged in the early 1990s and provided information on bacterial responses in their original soil environments. As a key procedure in the detection, extraction of bacterial RNA from soil has attracted much interest, and many methods of soil RNA extraction have been reported in the past 20 years. In addition to various RT-PCR-based technologies, new technologies for gene expression analysis, such as microarrays and high-throughput sequencing technologies, have recently been applied to examine bacterial gene expression in soil. These technologies are driving improvements in RNA extraction protocols. In this mini-review, progress in the extraction of bacterial RNA from soil is summarized with emphasis on the major difficulties in the development of methodologies and corresponding strategies to overcome them.
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Affiliation(s)
- Yong Wang
- Environmental Biofunction Division, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604, Japan.
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40
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Wenk J, Canonica S. Phenolic antioxidants inhibit the triplet-induced transformation of anilines and sulfonamide antibiotics in aqueous solution. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:5455-62. [PMID: 22510041 DOI: 10.1021/es300485u] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Recent studies have shown that dissolved organic matter (DOM) may inhibit the excited triplet-induced oxidation of several aromatic water contaminants, in particular those containing an aniline functionality. Such an inhibition was ascribed to antioxidant moieties of DOM. The present study was conducted with the aim of verifying whether well-defined antioxidants could act as inhibitors in analogy to DOM. Various substituted phenols exhibiting antioxidant character were able, at micromolar concentration, to slow down the photoinduced depletion of several anilines and sulfonamides in aerated aqueous solution containing 2-acetonaphthone as the photosensitizer. A concomitant accelerated degradation of the phenols in the presence of such contaminants was observed. This reinforces the hypothesis of reduction of oxidation intermediates of the contaminants by the phenols. Phenol (unsubstituted) was found to be a useful inhibitor even in the case of DOM-photosensitized transformations. Phenolic antioxidants are proposed as diagnostic tools to investigate the aquatic photochemistry of aromatic amines.
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Affiliation(s)
- Jannis Wenk
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
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41
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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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42
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Xiaoli C, Guixiang L, Xin Z, Yongxia H, Youcai Z. Fluorescence excitation-emission matrix combined with regional integration analysis to characterize the composition and transformation of humic and fulvic acids from landfill at different stabilization stages. WASTE MANAGEMENT (NEW YORK, N.Y.) 2012; 32:438-447. [PMID: 22104617 DOI: 10.1016/j.wasman.2011.10.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 10/08/2011] [Accepted: 10/11/2011] [Indexed: 05/31/2023]
Abstract
Fluorescence excitation-emission matrix spectroscopy (EEMs) combined with fluorescence regional integration (FRI) analysis was used to investigate the composition and transformation of humic acid (HA) and fulvic acid (FA) from landfill. The EEMs of HAs at different landfill ages were characterized by two typical fluorescence chromophores with Ex/Em pairs at Ex=420-470 nm/Em=490-530 nm and Ex=345-375 nm/Em=450-465 nm. EEMs of FA were featured by other two distinctly different fluorophores with Ex/Em pairs at Ex=315-335 nm/Em=420-440 nm and Ex=255-275 nm/Em=425-455 nm. The results show that HA extracted from the refuse disposed in the year of 1989 was formed by connecting small-condensed aromatic structures with protein-like chains. Compared with HA extracted from the refuse disposed in the year of 1992, HA extracted from the refuse of 1996 had a higher fluorescence intensity and lower r(()(B)(,)(A)()) (the ratio of the fluorescence intensities of peak B and peak A) value. It contained low molar mass components, low aromatic condensation degree, and more easily oxidized substituents. This indicates that the landfill time strongly affects the EEMs characteristics of HA, and that the humification degree of HA increases with the landfill time. A red shift to a longer wavelength region and an increase of fluorescence intensity were observed when the concentration of HA was increased, suggesting that concentration had a great influence on the fluorescence characteristics of HAs. pH (2-12) also had significant effects on the fluorescence intensity, although it exerted no effect on the peak position of fluorescence of HA and FA. The results of FRI show that increasing concentration lead to more interactions among various structure components and that small molecular weight units tend to aggregate or be masked into more complicated and larger structures. The pH influence on the fluorescence intensity of HA seems mainly through molecular configuration, while the fluorescence intensity change with pH may be due to various substituents of FA.
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Affiliation(s)
- Chai Xiaoli
- The State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.
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Hur J, Lee BM. Comparing the heterogeneity of copper-binding characteristics for two different-sized soil humic acid fractions using fluorescence quenching combined with 2D-COS. ScientificWorldJournal 2011; 11:1865-76. [PMID: 22125443 PMCID: PMC3217604 DOI: 10.1100/2011/640598] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 08/25/2011] [Indexed: 11/17/2022] Open
Abstract
Heterogeneous distributions of copper-binding characteristics were compared for two ultrafiltered size fractions of a soil HA using fluorescence quenching combined with two-dimensional correlation spectroscopy (2D-COS). The apparent shapes of the original synchronous fluorescence spectra and the extent of the fluorescence quenching upon the addition of copper were similar for the two fractions. The stability constants calculated at their highest peaks were not significantly different. However, the 2D-COS results revealed that the fluorescence quenching behaviors were strongly affected by the associated wavelengths and the fraction's size. The spectral change preferentially occurred in the wavelength order of 467 nm → 451 nm → 357 nm for the 1–10 K fraction and of 376 nm → 464 nm for the >100 K fraction. The extent of the binding affinities exactly followed the sequential orders interpreted from the 2D-COS, and they exhibited the distinctive ranges of the logarithmic values from 5.86 to 4.91 and from 6.48 to 5.95 for the 1–10 K and the >100 K fractions, respectively. Our studies demonstrated that fluorescence quenching combined with 2D-COS could be successfully utilized to give insight into the chemical heterogeneity associated with metal-binding sites within the relatively homogeneous HA size fractions.
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Affiliation(s)
- Jin Hur
- Department of Environment and Energy, Sejong University, Seoul 143-747, Republic of Korea.
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Caupos E, Mazellier P, Croue JP. Photodegradation of estrone enhanced by dissolved organic matter under simulated sunlight. WATER RESEARCH 2011; 45:3341-50. [PMID: 21530993 DOI: 10.1016/j.watres.2011.03.047] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2010] [Revised: 02/02/2011] [Accepted: 03/23/2011] [Indexed: 05/22/2023]
Abstract
In the present work the degradation of estrone (E1) a natural estrogenic hormone has been studied under simulated solar irradiation. The photodegradation of E1 has been investigated in the absence and in the presence of 7.7-8.9 mg L(-1) of dissolved organic carbon (DOC), under solar light simulation with irradiance approximating that of the sun. DOC extracts from different origins have been used. Half-lives ranging between 3.9 h and 7.9 h were observed. Results indicated that E1 was photodegraded even in the absence of DOC. The presence of DOC was found to enhance the degradation of E1. Experiments performed with the addition of reactive species scavengers (azide ions and 2-propanol) have shown that these two species play a significant role in the photodegradation. Some experiments have been performed with a DOC previously submitted to solar irradiation. Changes in optical and physico-chemical properties of DOC strongly affect its photoinductive properties, and hence its efficiency on E1 degradation. A part of the study consisted in the investigation of photoproducts structures. Five photoproducts were shown by chromatographic analysis: one arising from direct photolysis and the four others from DOC photoinduced degradation.
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Affiliation(s)
- Emilie Caupos
- Université de Poitiers, CNRS - UMR 6008, Laboratoire de Chimie et Microbiologie de l'Eau, ENSIP, Poitiers, France
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Dalrymple RM, Carfagno AK, Sharpless CM. Correlations between dissolved organic matter optical properties and quantum yields of singlet oxygen and hydrogen peroxide. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:5824-9. [PMID: 20593853 DOI: 10.1021/es101005u] [Citation(s) in RCA: 176] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Various aquatic dissolved organic matter (DOM) samples produce singlet oxygen (1O2) and hydrogen peroxide (H2O2) with quantum yields of 0.59 to 4.5% (1O2 at 365 nm) and 0.017 to 0.053% (H2O2, 300-400 nm integrated). The two species' yields have opposite pH dependencies and strong, but opposite, correlations with the E2/E3 ratio (A254 divided by A365). Linear regressions allow prediction of both quantum yields from E2/E3 in natural water samples with errors ranging from -3% to 60%. Experimental evidence and kinetic calculations indicate that less than six percent of the H2O2 is produced by reaction between 1O2 and DOM. The inverse relationship between the 1O2 and H2O2 yields is thus best explained by a model in which precursors to these species are populated competitively. A model is presented, which proposes that important precursors to H2O2 may be either charge-transfer or triplet states of DOM.
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Affiliation(s)
- Renée M Dalrymple
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
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46
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Sensitizing effect of bio-based chemicals from urban wastes on the photodegradation of azo-dyes. J Photochem Photobiol A Chem 2010. [DOI: 10.1016/j.jphotochem.2009.11.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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He D, Guan X, Ma J, Yu M. Influence of different nominal molecular weight fractions of humic acids on phenol oxidation by permanganate. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:8332-8337. [PMID: 19924965 DOI: 10.1021/es901700m] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The effects of humic acid (HA) and its different nominal molecular weight (NMW) fractions on the phenol oxidation by permanganate were studied. Phenol oxidation by permanganate was enhanced by the presence of HA at pH 4-8, while slightly inhibited at pH 9-10. The effects of HA on phenol oxidation by permanganate were dependent on HA concentration and permanganate/phenol molar ratios. The high NMW fractions of HA enhanced phenol oxidation by permanganate at pH 7 more significantly than the low fractions of HA. The apparent second-order rate constants of phenol oxidation by permanganate in the presence of HA correlated well with their specific ultraviolet absorption (SUVA) at 254 nm and specific violet absorption (SVA) at 465 or 665 nm. High positive correlation coefficients (R(2) > 0.72) implied that pi-electrons of HA strongly influenced the reactivity of phenol towards permanganate oxidation which agreed well with the information provided by fluorescence spectroscopy. The FTIR analysis indicated that the HA fractions rich in aliphatic character, polysaccharide-like substances, and the amount of carboxylate groups had less effect on phenol oxidation by permanganate. The negative correlation between the rate constants of phenol oxidation by permanganate and O/C ratios suggested that the oxidation of phenol increased with a decrease in the content of oxygen-containing functional groups.
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Affiliation(s)
- Di He
- State Key Lab of Urban Water Resource and Environment (HIT), Harbin Institute of Technology, Harbin, P. R. China
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Yu C, Chen S, Quan X, Ou X, Zhang Y. Separation of phthalocyanine-like substances from humic acids using a molecular imprinting method and their photochemical activity under simulated sunlight irradiation. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2009; 57:6927-6931. [PMID: 19591473 DOI: 10.1021/jf9016459] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
To elucidate the existence of phthalocyanine-like (Pc-like) substances in humic acids (HA) and their roles in photochemical transformation of organic pollutants, Pc-imprinted polymers (MIP) were synthesized successfully and employed to separate Pc-like substances from HA. The fraction bound by MIP (F(mip-b)) presented better photochemical activity for degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution irradiated by simulated sunlight. The pseudo-first-order rate constant of 2,4-D photodegradation with the presence of F(mip-b) was 2.5 times as high as that in solution containing effluent fraction (F(eff)). These results show the key role of some HA with special structures in photochemistry and are helpful for better understanding phototransformation of environmental contaminants in natural aquatic systems.
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Affiliation(s)
- Chunyan Yu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024, China
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Cavani L, Halladja S, ter Halle A, Guyot G, Corrado G, Ciavatta C, Boulkamh A, Richard C. Relationship between photosensitizing and emission properties of peat humic acid fractions obtained by tangential ultrafiltration. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:4348-4354. [PMID: 19603645 DOI: 10.1021/es802964m] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Peat humic acid was fractionated by tangential ultrafiltration into six nominal molecular weight (NMW) fractions, HA5-10, HA10-20, HA20-50, HA50-100, HA100-300 and HA > 300, which were purified by dialysis using a 0.5 kDa membrane. The absorbing and emission properties of the separated fractions were compared and their ability to generate singlet oxygen under light excitation was evaluated, using furfuryl alcohol (FFA) as a singlet oxygen scavenger. The absorbance, the emission intensity, and the apparent first order rate constants of FFA loss were normalized per mole of organic carbon (a*, IF*, and k*, respectively). The fraction absorbance decreased with NMW, except for HA > 300 which was less absorbing than HA100-300. The low NMW fractions and the HA > 300 fraction generally showed lower k* and IF* values compared to the HA50-100 and HA100-300 fractions. A plot of k* versus IF* indicates that the first order rate constant of FFA photo-oxygenation increased with the intensity of fluorescence at 380, 430, and 500 nm (R2 = 0.77-0.84). This shows that the distribution of fluorescent centers among fractions paralleled that of photosensitizing centers. Plotting k* or IF* versus a* at365 nm reveals the apparent relative quantum efficiency of the different fractions. Higher values for low NMW fractions and HA50-100 are either due higher percentages of absorbing centers able to produce singlet oxygen or exhibit fluorescence or to lower quenching processes.
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Affiliation(s)
- Luciano Cavani
- Dipartimento di Scienze e Tecnologie Agroambientali, Alma Mater Studiorum-Università di Bologna, Viale Fanin 40, 40127 Bologna, Italy
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Gieguzynska E, Amine-Khodja A, Trubetskoj OA, Trubetskaya OE, Guyot G, Ter Halle A, Golebiowska D, Richard C. Compositional differences between soil humic acids extracted by various methods as evidenced by photosensitizing and electrophoretic properties. CHEMOSPHERE 2009; 75:1082-1088. [PMID: 19232425 DOI: 10.1016/j.chemosphere.2009.01.047] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 01/07/2009] [Accepted: 01/08/2009] [Indexed: 05/27/2023]
Abstract
Humic acids (HAs) were isolated from Elliott soil provided by the International Humic Substances Society (1BS102M) by three commonly used methods: (i) 0.1M NaOH (EI-HA), (ii) neutral 0.1M Na(4)P(2)O(7) (L-HA) and subsequent 0.1M NaOH (S-HA), and (iii) 0.1M NaOH+0.1M Na(4)P(2)O(7) (NP-HA). The objective was to evaluate the impact of these extractants on the photosensitizing properties of the isolated HAs. HAs were analyzed for their elemental composition, functional acid groups content, absorption and emission properties, electrophoretic characteristics and ability to produce singlet oxygen using furfuryl alcohol (FFA) as a scavenger. L-HA was slightly more aromatic and oxygenated than the other HAs and contained a higher portion of long-wavelength fluorophores and macromolecules showing low molecular size (MS) and high electrophoretic mobility. L-HA also gave a rate of FFA photooxygenation between 1.25- and 1.6-fold higher than the other HAs. This suggests that the free humic macromolecules ionized at pH 7 and/or weakly bounded on mineral surfaces via cation bridges are of relatively low MS and contribute significantly to the photosensitizing and long-wavelength emitting properties. Differences among the other HAs were more subtle, but the parallel evolution of the reactivity and electrophoretic characteristics was observed. Photochemical and electrophoretic measurements seem to be sensitive indicators to evaluate differences among the extraction procedures of HAs.
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Affiliation(s)
- E Gieguzynska
- Department of Physics, University of Agriculture, ul. Janosika 8, 71-424 Szczecin, Poland
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