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Wang X, Pu L, Sun Z, Fang G, Wang Y, Gu C, Gao J. Comparative study of the photooxidation of arsenite mediated by dissolved and mineral-associated humic acid under light irradiation. JOURNAL OF HAZARDOUS MATERIALS 2024; 462:132759. [PMID: 37832435 DOI: 10.1016/j.jhazmat.2023.132759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 09/18/2023] [Accepted: 10/09/2023] [Indexed: 10/15/2023]
Abstract
The photochemical processes of dissolved humic acid and its potential contribution to As(III) oxidation in natural water has received considerable attention. However, the role of mineral-humic complexes in As(III) conversion is rarely studied. Herein, two simulated mineral-humic complexes were prepared by coating humic acid on hydrous aluminum oxide, HA@HAO, or montmorillonite, HA@SWy, respectively, and batch experiments at circumneutral pH were performed under light irradiation. Our findings showed that the light-assisted oxidation of As(III) increased with increasing fractions of organic carbon in mineral-humic complexes, and As(III) photooxidation with HA@HAO or HA@SWy was up to 18.2 or 3.5-fold higher compared to that measured in the presence of equivalent amount of free HA, respectively. The reactive triplet state of HA and hydroxyl radicals in HA@HAO and HA@SWy system made a primary contribution to As(III) oxidation under irradiation. The results indicated that mineral-humic complexes have dual roles, an adsorbent and a photosensitizer, to promote As(III) access to reactive intermediates at the particle surfaces. This process was important for As(III) conversion in paddy water as colloidal particles, composed of both minerals and HA, could greatly promote As(III) oxidation and As(V) immobilization. This study provides a previously overlooked, important mechanism of As(III) phototransformation mediated by mineral-associated humic acid in natural environment.
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Affiliation(s)
- Xinghao Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Lirong Pu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Zhaoyue Sun
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Guodong Fang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yujun Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Cheng Gu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Juan Gao
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Nanjing 211135, China.
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Zhou Z, Yang L, Qu X, Fu H. Dissolved black carbon mediated photo-oxidation of arsenic(III) to arsenic(V) in water: The key role of triplet states. CHEMOSPHERE 2024; 347:140718. [PMID: 37972870 DOI: 10.1016/j.chemosphere.2023.140718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 11/03/2023] [Accepted: 11/12/2023] [Indexed: 11/19/2023]
Abstract
Arsenic is a common contaminant found in natural waters, and has raised significant environmental concerns due to its toxicity and carcinogenicity. In this study, we investigated the mediated photo-oxidation of arsenite (As(III)) under simulated sunlight by dissolved black carbon (DBC), an important dissolved organic matter (DOM) constituent released from black carbon. Five DBC were collected from the water extracts of black carbons that were derived by pyrolyzing different biomass (i.e., bamboo, rice, peanuts, corn, and sorghum stalks), and four well-studied dissolved humic substances (DHS) were selected for benchmarking. The presence of DBC (i.e., 5 mg C-1) significantly accelerated the photo-oxidation of As(III) to arsenate (As(V)), with the observed pseudo-first-order rate constant of reaction increased by 5∼11 times. Quenching experiments of photochemically produced reactive intermediates suggested that As(III) was mainly oxidized by triplet-excited DBC (3DBC*, contribution of 48%), singlet oxygen (1O2, 18%) and superoxide anions (O2•-, 28%) in sunlight-irradiated DBC solutions. The average apparent quantum yield of As(III) photo-oxidation for DBC was found to be more than 4 times higher in comparison with DHS. Such a strong mediation efficiency of DBC was due to its smaller molecular size and higher aromaticity than DHS, which facilitated the non-charge-transfer process to produce triplet-excited states and their sensitized 1O2. Consistently, DBC exhibited a higher apparent quantum yield and a longer lifetime of triplet states as compared with DHS. The results imply that DBC may play a previously unrecognized important role in the fate of arsenic in aquatic environments.
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Affiliation(s)
- Zhicheng Zhou
- State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment, Nanjing University, Jiangsu 210046, China
| | - Lanqing Yang
- State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment, Nanjing University, Jiangsu 210046, China
| | - Xiaolei Qu
- State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment, Nanjing University, Jiangsu 210046, China
| | - Heyun Fu
- State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment, Nanjing University, Jiangsu 210046, China.
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3
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Wu Y, Huang X, Xu J, Huang W, Li J, Mailhot G, Wu F. Insight into the effect of natural organic matter on the photooxidation of arsenite induced by colloidal ferric hydroxides in water. WATER RESEARCH 2023; 232:119683. [PMID: 36739662 DOI: 10.1016/j.watres.2023.119683] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/26/2023] [Accepted: 01/29/2023] [Indexed: 06/18/2023]
Abstract
Surface complexation of arsenite (As(III)) on colloidal ferric hydroxide (CFH) plays an important role not only in the adsorptive immobilization of As(III) but also in the subsequent oxidation of As(III) to arsenate (As(V)) through light-induced ligand-to-metal charge transfer (LMCT) in water at near-neutral pH. However, the effects of natural organic matter (NOM), especially humic substances (HSs) and low molecular weight carboxylic acids (CAs), on the photochemistry of the CFH-As(III) system have not been sufficiently understood. In this work, the inhibition of photooxidation of As(III) in terms of the observed apparent rate constant (kobs) by six HSs (below 16 mg L-1) and seven CAs (below 2.5 mM) has been observed in water containing 66 μM Fe(III) and 5 μM As(III) at pH 7 under simulated solar irradiation consisting of UVA (λmax 365 nm) and UVB (λmax 313 nm) lights. Total inhibition factors (T) have been determined from the combined effect of light-screening factor (S) and competitive complexation factor (C), wherein both S and C varied with NOM concentration. S was obtained by determining the absorbance of NOM, and C was obtained by fitting modified Langmuir or Freundlich models to the amount of As(III) desorbed from CFH upon the addition of NOM. Statistical analysis between the experimental Texp and the calculated one according to Tcal = S × C showed that the Freundlich model (RMSE for HS 0.1609 and for CA 0.1771) was better than the Langmuir model and was statistically robust (QLOO2= 0.691 > 0.5). This work provided an estimation method for the effects of NOM on As(III) photooxidation in the presence of CFH as well as a deeper understanding of the transformation of arsenic species in sunlit water.
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Affiliation(s)
- Yi Wu
- Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, Wuhan 430079, PR China
| | - Xingyun Huang
- Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, Wuhan 430079, PR China
| | - Jing Xu
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, PR China.
| | - Wenyu Huang
- School of Resources, Environment and Materials, Guangxi University, 100 Daxue East Road, Nanning 530004, PR China.
| | - Jinjun Li
- Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, Wuhan 430079, PR China
| | - Gilles Mailhot
- Universite Clermont Auvergne, CNRS, Clermont Auvergne INP, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France
| | - Feng Wu
- Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, Wuhan 430079, PR China.
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Wang NX, Chen ZY, Zhou WQ, Zhang W. Influence of humic acid and fluvic acid on the altered toxicities of arsenite and arsenate toward two freshwater algae. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2022; 249:106218. [PMID: 35704967 DOI: 10.1016/j.aquatox.2022.106218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 06/04/2022] [Accepted: 06/06/2022] [Indexed: 06/15/2023]
Abstract
Arsenic pollution in freshwater poses a serious threat to aquatic organisms. However, dissolved organic matter (DOM) in water can modulate arsenic environmental toxicity by either suppressing or promoting its bioaccumulation. In this study, we investigated the toxicity, bioaccumulation, and biotransformation of inorganic arsenic (arsenite AsIII and arsenate AsV) combined with two types of DOM, i.e., humic acid (HA) and fulvic acid (FA), in the algae Chlamydomonas reinhardtii and Ochromonas danica. C. reinhardtii has a cell wall and cannot bioaccumulate arsenic complexation, whereas O. danica has no cell wall. Without DOM, AsV was more toxic than AsIII for C. reinhardtii, and AsV was less toxic than AsIII for O. danica. HA and FA addition reduced AsV and AsIII toxicities; the larger molecular weight (Mw) of HA contributed to the reduction in toxicity to an even greater extent, and reduced arsenic accumulation while promoting the biotransformation ability of C. reinhardtii, which has a cell wall. However, HA and FA addition increased AsV and AsIII toxicities and arsenic accumulation while relatively enhancing the biotransformation ability of O. danica, which has no cell wall. Coupling toxicity, bioaccumulation, and biotransformation, DOM (HA and FA) contributed to the altered toxicity of freshwater algae to AsV and AsIII through reduced/increased arsenic accumulation and enhanced biotransformation. Overall, our study considered the combined toxicity of inorganic arsenic and DOM in phytoplankton, helping estimate the potential environmental risk of arsenic in aqueous environments.
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Affiliation(s)
- Ning-Xin Wang
- School of Environmental Engineering, Nanjing Institute of Technology, Nanjing 211167, China
| | - Zheng-Yu Chen
- School of Environmental Engineering, Nanjing Institute of Technology, Nanjing 211167, China
| | - Wen-Qiang Zhou
- Academy of Environmental Planning & Design, Co., Ltd., Nanjing University, Nanjing 210093, China
| | - Wei Zhang
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Institute of Environmental Research at Greater Bay Area, Guangzhou University, Guangzhou 510006, China.
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Remke SC, Bürgin TH, Ludvíková L, Heger D, Wenger OS, von Gunten U, Canonica S. Photochemical oxidation of phenols and anilines mediated by phenoxyl radicals in aqueous solution. WATER RESEARCH 2022; 213:118095. [PMID: 35203017 DOI: 10.1016/j.watres.2022.118095] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/14/2022] [Accepted: 01/15/2022] [Indexed: 06/14/2023]
Abstract
Reactive intermediates formed upon irradiation of chromophoric dissolved organic matter (CDOM) contribute to the degradation of various organic contaminants in surface waters. Besides well-studied "short-lived" photooxidants, such as triplet state CDOM (3CDOM*) or singlet oxygen, CDOM-derived "long-lived" photooxidants (LLPO) have been suggested as key players in the transformation of electron-rich contaminants. LLPO were hypothesized to mainly consist of phenoxyl radicals derived from phenolic moieties in the CDOM. To test this hypothesis and to better characterize LLPO, the transformation kinetics of selected target compounds (phenols and anilines) induced by a suite of electron-poor model phenoxyl radicals was studied in aerated aqueous solution at pH 8. The phenoxyl radicals were generated by photosensitized oxidation of the parent phenols using aromatic ketones as photosensitizers. Under steady-state irradiation, the presence of any of the electron-poor phenols lead to an enhanced abatement of the phenolic target compounds (at an initial concentration of 1.0 × 10-7 M) compared to solutions containing the photosensitizer but no electron-poor phenol. A trend of increasing reactivity with increasing one-electron reduction potential of the electron-poor phenoxyl radical (range: 0.85‒1.12 V vs. standard hydrogen electrode) was observed. Using the excited triplet state of 2-acetonaphthone as a selective oxidant for phenols, it was observed that the reactivity correlated with the concentration of electron-poor phenoxide present in solution. The rates of transformation of anilines induced by the 4-cyanophenoxyl radical were an order of magnitude smaller than for the phenolic target compounds. This was interpreted as a reduction of the radical intermediates back to the parent compound by the superoxide radical anion. Laser flash photolysis measurements confirmed the formation of the 4-cyanophenoxyl radical in solutions containing 2-acetonaphthone and 4-cyanophenol, and yielded values of (2.6 - 5.3) × 108 M-1 s-1 for the second-order rate constant for the reaction of this radical with 2,4,6-trimethylphenol. These and further results indicate that electron-poor model phenoxyl radicals generated through photosensitized oxidation are useful models to understand the photoreactivity of LLPO as part of the CDOM.
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Affiliation(s)
- Stephanie C Remke
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, Dübendorf, CH 8600, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH 1015, Switzerland
| | - Tobias H Bürgin
- Department of Chemistry, University of Basel, Basel 4056, Switzerland
| | - Lucie Ludvíková
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, Brno 62500, Czech Republic; RECETOX, Faculty of Science, Masaryk University, Kamenice 5, Brno 62500, Czech Republic; Present address: PASTEUR, Département de chimie, École normale supérieure, PSL University, Sorbonne University, CNRS, Paris 75005, France
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, Brno 62500, Czech Republic
| | - Oliver S Wenger
- Department of Chemistry, University of Basel, Basel 4056, Switzerland
| | - Urs von Gunten
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, Dübendorf, CH 8600, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH 1015, Switzerland
| | - Silvio Canonica
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, Dübendorf, CH 8600, Switzerland.
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Key Points of Advanced Oxidation Processes (AOPs) for Wastewater, Organic Pollutants and Pharmaceutical Waste Treatment: A Mini Review. CHEMENGINEERING 2022. [DOI: 10.3390/chemengineering6010008] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Advanced oxidation procedures (AOPs) refer to a variety of technical procedures that produce OH radicals to sufficiently oxidize wastewater, organic pollutant streams, and toxic effluents from industrial, hospital, pharmaceutical and municipal wastes. Through the implementation of such procedures, the (post) treatment of such waste effluents leads to products that are more susceptible to bioremediation, are less toxic and possess less pollutant load. The basic mechanism produces free OH radicals and other reactive species such as superoxide anions, hydrogen peroxide, etc. A basic classification of AOPs is presented in this short review, analyzing the processes of UV/H2O2, Fenton and photo-Fenton, ozone-based (O3) processes, photocatalysis and sonolysis from chemical and equipment points of view to clarify the nature of the reactive species in each AOP and their advantages. Finally, combined AOP implementations are favored through the literature as an efficient solution in addressing the issue of global environmental waste management.
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Zeng Y, Fang G, Fu Q, Dionysiou DD, Wang X, Gao J, Zhou D, Wang Y. Photochemical characterization of paddy water during rice cultivation: Formation of reactive intermediates for As(III) oxidation. WATER RESEARCH 2021; 206:117721. [PMID: 34624658 DOI: 10.1016/j.watres.2021.117721] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/24/2021] [Accepted: 09/25/2021] [Indexed: 06/13/2023]
Abstract
Although the photochemical behavior of surface water and its effects on pollutant transformation have been studied extensively in recent years, the photochemistry of paddy water remains largely unknown. In this study, we examined the photochemical processes involving paddy water samples collected at four different cultivation stages of rice. Triplet dissolved organic matter (3DOM*), singlet oxygen (1O2), and hydroxyl radicals (•OH) were found to be the dominant reactive intermediates (RIs), and their apparent quantum yields and steady-state concentrations were quantified. Compared with the typical surface water, quantum yields of 3DOM* and •OH were comparable, while quantum yields of 1O2 were about 2.4-6.7 times higher than those of surface water. Fluorescence emission-excitation matrix (EEM) spectra, Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), and statistical analysis revealed that DOM properties and nitrite concentration were the main factor influencing RIs generation. The results suggest that DOM with lower molecular weight and humification extent generated more RIs, and nitrite contributed to 23.9%-100% of •OH generation. EEM and FTICR-MS data showed that DOM with more saturated and less aromatic formulas could produce more 3DOM* under the irradiation, while the polyphenolic components of DOM inhibited the formation of RIs. Moreover, RIs significantly enhanced arsenite (As(III)) oxidation with oxidation rate increased by 1.8-4.1 times in paddy water, and •OH and 3DOM* were the main RIs responsible for As(III) oxidation. This study provides new insight into the pathways of arsenite abiotic transformation in paddy soil and water.
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Affiliation(s)
- Yu Zeng
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Guodong Fang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Qinglong Fu
- School of Environmental Studies, China University of Geoscience, Wuhan 430074, PR China
| | - Dionysios D Dionysiou
- Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering (ChEE), University of Cincinnati, Cincinnati, OH 45221-0071, USA
| | - Xiaolei Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Juan Gao
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Dongmei Zhou
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Yujun Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR 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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Wang Z, Fu Y, Wang L. Abiotic oxidation of arsenite in natural and engineered systems: Mechanisms and related controversies over the last two decades (1999-2020). JOURNAL OF HAZARDOUS MATERIALS 2021; 414:125488. [PMID: 33676246 DOI: 10.1016/j.jhazmat.2021.125488] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 02/17/2021] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
Abiotic oxidation of toxic As(III) to As(V) is being deemed as a necessary step for the overall arsenic decontamination in both natural and engineered systems. Direct oxidation of As(III) by chemical oxidants, such as ozone, permanganate, ferrate, chlorine and chloramine, or naturally occurring minerals like Mn, Fe oxides, seems straightforward. Both O2 and H2O2 are ineffective for arsenite oxidation, but they can be activated by reducing substances like Fe2+, Fe0 to increase the oxidation rates. Photo-induced oxidation of As(III) has been demonstrated effective in Fe complexes or minerals, NO3-/NO2-, dissolved organic matter (DOM), peroxygens and TiO2 systems. Although a variety of oxidation methods have been developed over the past two decades, there remain many scientific and technical challenges that must be overcome before the rapid progress in basic knowledge can be translated into environmental benefits. To better understand the trends in the existing data and to identify the knowledge gaps, this review describes in detail the complicated mechanisms for As(III) oxidation by various methods and emphasizes on the conflicting data and explanation. Some prevailing concerns and challenges in the sphere of As(III) oxidation are also pointed out so as to appeal to researchers for further investigations.
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Affiliation(s)
- Zhaohui Wang
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China; Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, Shanghai 200241, China; Technology Innovation Center for Land Spatial Eco-restoration in Metropolitan Area, Ministry of Natural Resources, 3663N. Zhongshan Road, Shanghai 200062, China.
| | - Yu Fu
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Lingli Wang
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
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10
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Huang X, Peng Y, Xu J, Wu F, Mailhot G. Iron(III)-induced photooxidation of arsenite in the presence of carboxylic acids and phenols as model compounds of natural organic matter. CHEMOSPHERE 2021; 263:128142. [PMID: 33297130 DOI: 10.1016/j.chemosphere.2020.128142] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 08/20/2020] [Accepted: 08/25/2020] [Indexed: 06/12/2023]
Abstract
Iron species have essential influence on the environmental/geochemical behaviors of arsenic species in water and soil. Colloidal ferric hydroxide (CFH) induces photooxidation of arsenite (As(III)) to arsenate (As(V)) in water at neutral pH through surface complexation and ligand-to-metal charge transfer (LMCT). However, the effect of the co-existing natural organic matter (NOM) on the complexation-photolysis in this process has remained unclear. In the present work, the photooxidation of As(III) induced by CFH was investigated in the presence of various carboxylic acids and polyphenols as simple model compounds of NOM. Two different light sources of ultraviolet A (UVA) (λmax = 365 nm) and ultraviolet B (UVB) (λmax = 313 nm) were used for photooxidation treatment of the experimental ternary system and the control binary system respectively. The obtained results demonstrated that all investigated NOM inhibited the photooxidation of As(III) in the As(III)/CFH system at pH 7. Moreover, the correlation analysis between the pseudo-first order rate constant kobs and various property parameters of NOM showed that the stable constant for the complexation between Fe(III) and NOM (logKFe-NOM) as well as the molecular weight of NOM and the percentages of total acidity of NOM exhibited significant correlations. A simple quantitative structure-activity relationship (QSAR) model was established between kobs and these three parameters utilizing a multiple linear regression method, which can be employed to estimate the photooxidation efficiency of As(III) in the presence of ferric iron and NOM. Thus, the present work contributes to the understanding of the environmental interactions between NOM and iron.
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Affiliation(s)
- Xingyun Huang
- School of Resources and Environmental Science, Wuhan University, Wuhan, 430079, PR China
| | - Ying Peng
- School of Resources and Environmental Science, Wuhan University, Wuhan, 430079, PR China; Hubei Academy of Environmental Science, Wuhan, 430072, PR China
| | - Jing Xu
- School of Water Resources and Hydropower Engineering, Wuhan University, Wuhan, 430079, PR China.
| | - Feng Wu
- School of Resources and Environmental Science, Wuhan University, Wuhan, 430079, PR China
| | - Gilles Mailhot
- Université Clermont Auvergne, CNRS, SIGMA Clermont, Institut de Chimie de Clermont-Ferrand, F-63000, Clermont-Ferrand, France.
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Removal of As(III) from Water Using the Adsorptive and Photocatalytic Properties of Humic Acid-Coated Magnetite Nanoparticles. NANOMATERIALS 2020; 10:nano10081604. [PMID: 32824146 PMCID: PMC7466695 DOI: 10.3390/nano10081604] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/31/2020] [Accepted: 08/11/2020] [Indexed: 11/17/2022]
Abstract
The oxidation of highly toxic arsenite (As(III)) was studied using humic acid-coated magnetite nanoparticles (HA-MNP) as a photosensitizer. Detailed characterization of the HA-MNP was carried out before and after the photoinduced treatment of As(III) species. Upon irradiation of HA-MNP with 350 nm light, a portion of the As(III) species was oxidized to arsenate (As(V)) and was nearly quantitatively removed from the aqueous solution. The separation of As(III) from the aqueous solution is primarily driven by the strong adsorption of As(III) onto the HA-MNP. As(III) removals of 40–90% were achieved within 60 min depending on the amount of HA-MNP. The generation of reactive oxygen species (•OH and 1O2) and the triplet excited state of HA-MNP (3HA-MNP*) was monitored and quantified during HA-MNP photolysis. The results indicate 3HA-MNP* and/or singlet oxygen (1O2) depending on the reaction conditions are responsible for converting As(III) to less toxic As(V). The formation of 3HA-MNP* was quantified using the electron transfer probe 2,4,6-trimethylphenol (TMP). The formation rate of 3HA-MNP* was 8.0 ± 0.6 × 10−9 M s−1 at the TMP concentration of 50 µM and HA-MNP concentration of 1.0 g L−1. The easy preparation, capacity for triplet excited state and singlet oxygen production, and magnetic separation suggest HA-MNP has potential to be a photosensitizer for the remediation of arsenic (As) and other pollutants susceptible to advanced oxidation.
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Pothier MP, Lenoble V, Garnier C, Misson B, Rentmeister C, Poulain AJ. Dissolved organic matter controls of arsenic bioavailability to bacteria. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 716:137118. [PMID: 32059299 DOI: 10.1016/j.scitotenv.2020.137118] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/14/2020] [Accepted: 02/03/2020] [Indexed: 06/10/2023]
Abstract
The presence of arsenic in irrigation and drinking waters is a threat to worldwide human health. Dissolved organic matter (DOM) is a ubiquitous and photoreactive sorbent of arsenic, capable of both suppressing and enhancing its mobility. Microbes can control the mobilization of mineral-bound arsenic, through redox processes thought to occur intracellularly. The role that DOM plays on the bioavailability of arsenic to microbes is often invoked but remains untested experimentally. Here, using a whole-cell biosensor, we tested the role of DOM on As(III) and As(V) bioavailability. Using cation amendments, we explored the nature of As-DOM interactions. We found As bioavailability to be dependent on [As]/[DOM] ratio and on the strength of As binding to DOM which varied as a function of time. We further tested the role of DOM on As(III) photooxidation and showed that As(III) photooxidation rate is limited by the strength of its interactions with DOM and sensitive to ionic competitive desorption. Our study demonstrates the dynamic control that photoreactive DOM poses on the bioavailability and reactivity of As in the environment and highlights the kinetic controls that DOM can possibly exert on As toxicity at various levels in foodwebs.
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Affiliation(s)
- Martin P Pothier
- Biology Department, University of Ottawa, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada
| | - Véronique Lenoble
- Univ. Toulon, Aix Marseille Univ., CNRS/INSU, IRD, MIO UM 110, Mediterranean Institute of Oceanography, La Garde, France
| | - Cédric Garnier
- Univ. Toulon, Aix Marseille Univ., CNRS/INSU, IRD, MIO UM 110, Mediterranean Institute of Oceanography, La Garde, France
| | - Benjamin Misson
- Univ. Toulon, Aix Marseille Univ., CNRS/INSU, IRD, MIO UM 110, Mediterranean Institute of Oceanography, La Garde, France
| | - Charlotte Rentmeister
- Biology Department, University of Ottawa, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada
| | - Alexandre J Poulain
- Biology Department, University of Ottawa, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada.
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Li S, Dao GH, Tao Y, Zhou J, Jiang HS, Xue YM, Yu WW, Yong XL, Hu HY. The growth suppression effects of UV-C irradiation on Microcystis aeruginosa and Chlorella vulgaris under solo-culture and co-culture conditions in reclaimed water. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 713:136374. [PMID: 31955073 DOI: 10.1016/j.scitotenv.2019.136374] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 12/25/2019] [Accepted: 12/26/2019] [Indexed: 06/10/2023]
Abstract
Harmful algal blooms (HABs) are serious problems in landscape waters sourced from reclaimed water. In this study, the suppression effects of UV-C irradiation on microalgal growth were researched to find a possible preventive approach. Microcystis aeruginosa and Chlorella vulgaris were exposed to UV-C irradiation and then cultured in real reclaimed water for 7-18 d. UV-C irradiation at 50-200 mJ cm-2 could inhibit the growth of M. aeruginosa, C. vulgaris, and both microalgae in co-culture for 3-14, 1-3, and 1-5 d respectively. In addition, UV-C irradiation could cause damage to the cell integrity. At 100-200 mJ cm-2 UV-C, the proportion of microalgal membrane damage (Pmd) in M. aeruginosa cells increased rapidly to 56%-76% from day 3, whereas that in C. vulgaris cells increased to 23%-62% within 3 d. The photochemical efficiency (represented by Y value) of the irradiated groups was negatively affected immediately after UV-C irradiation and recovered gradually during the incubation. The Y value of M. aeruginosa cells began to recover from days 3 to 14, whereas that of C. vulgaris recovered much more quickly, from days 0.1 to 1. Overall, the irradiation-induced suppressive effects on algal growth correlated positively with the UV-C doses. Because M. aeruginosa was more sensitive to UV-C irradiation, UV-C irradiation not only controlled the total biomass of the mixed algae but also selectively reestablished the dominance of the nontoxic C. vulgaris.
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Affiliation(s)
- Shang Li
- Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, China
| | - Guo-Hua Dao
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China
| | - Yi Tao
- Key Laboratory of Microorganism Application and Risk Control (MARC) of Shenzhen, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
| | - Ji Zhou
- Chengdu Xingrong Environmental Co., Ltd., Chengdu 610041, China
| | - Hai-Sha Jiang
- Chengdu Xingrong Environmental Co., Ltd., Chengdu 610041, China
| | - Yuan-Mei Xue
- Chengdu Xingrong Environmental Co., Ltd., Chengdu 610041, China
| | - Wen-Wen Yu
- Chengdu Xingrong Environmental Co., Ltd., Chengdu 610041, China
| | - Xiao-Lei Yong
- Chengdu Xingrong Environmental Co., Ltd., Chengdu 610041, China
| | - Hong-Ying Hu
- Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, China; Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China.
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Biswas A, Besold J, Sjöstedt C, Gustafsson JP, Scheinost AC, Planer-Friedrich B. Complexation of Arsenite, Arsenate, and Monothioarsenate with Oxygen-Containing Functional Groups of Natural Organic Matter: An XAS Study. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:10723-10731. [PMID: 31436974 DOI: 10.1021/acs.est.9b03020] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Arsenic (As) is reported to be effectively sorbed onto natural organic matter (NOM) via thiol coordination and polyvalent metal cation-bridged ternary complexation. However, the extent of sorption via complexation with oxygen-containing functional groups of NOM is poorly understood. By equilibrating arsenite, arsenate, and monothioarsenate with purified model-peat, followed by As K-edge X-ray absorption spectroscopic analysis, this study shows that complexation with oxygen-containing functional groups can be an additional or alternative mode of As sorption to NOM. The extent of complexation was highest for arsenite, followed by monothioarsenate and arsenate. Complexation was higher at pH 7.0 compared to 4.5 for arsenite and arsenate and vice versa for monothioarsenate because of partial transformation to arsenite at pH 4.5. Modeling of the As K-edge extended X-ray absorption fine structure data revealed that As···C interatomic distances were relatively longer in arsenate- (2.83 ± 0.01 Å) and monothioarsenate-treated peat (2.80 ± 0.02 Å) compared to arsenite treatments (2.73 ± 0.01 Å). This study suggests that arsenite was predominantly complexed with carboxylic groups, whereas arsenate and monothioarsenate were complexed with alcoholic groups of the peat. This study further implies that in systems, where NOM is the major sorbent, arsenate and monothioarsenate can have higher mobility than arsenite.
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Affiliation(s)
- Ashis Biswas
- Department of Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BAYCEER) , Bayreuth University , 95440 Bayreuth , Germany
- Department of Earth and Environmental Sciences , Indian Institute of Science Education and Research (IISER) Bhopal , Bhopal Bypass Road , 462066 Bhauri , Madhya Pradesh , India
| | - Johannes Besold
- Department of Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BAYCEER) , Bayreuth University , 95440 Bayreuth , Germany
| | - Carin Sjöstedt
- Department of Soil and Environment , Swedish University of Agricultural Sciences , Box 7014, 750 07 Uppsala , Sweden
| | - Jon Petter Gustafsson
- Department of Soil and Environment , Swedish University of Agricultural Sciences , Box 7014, 750 07 Uppsala , Sweden
| | - Andreas C Scheinost
- The Rossendorf Beamline (ROBL) at ESRF , 38043 Grenoble , France
- Institute of Resource Ecology , Helmholtz-Zentrum Dresden-Rossendorf (HZDR) , Bautzner Landstraße 400 , 01328 Dresden , Germany
| | - Britta Planer-Friedrich
- Department of Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BAYCEER) , Bayreuth University , 95440 Bayreuth , Germany
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Jin J, Chen Z, Song X, Wu B, Zhang G, Zhang S. Effects of acetylacetone on the thermal and photochemical conversion of benzoquinone in aqueous solution. CHEMOSPHERE 2019; 223:628-635. [PMID: 30798058 DOI: 10.1016/j.chemosphere.2019.02.080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 01/08/2019] [Accepted: 02/13/2019] [Indexed: 06/09/2023]
Abstract
Quinones are components of electron transport chains in photosynthesis and respiration. Acetylacetone (AA), structurally similar to benzoquinone (BQ) for the presence of two identical carbonyl groups, has been reported as a quinone-like electron shuttle. Both BQ and AA are important chemicals in the aquatic environment. However, little information is known about their interactions if co-existed. We found here that AA significantly enhanced the conversion of BQ. By analyzing the evolution of chemical concentration, solution pH, dissolved oxygen, and the final products, the interactions between AA and BQ were elucidated. The reactions between BQ and AA generated oxygen but ultimately led to the reduction of solution pH and dissolved oxygen. The reactions proceeded faster under indoor lighting condition than in the dark. The formation of semiquinone radicals is believed as the primary step. The secondary AA-derived radicals might be strongly oxidative or reductive, depending on the concentration of dissolved oxygen. Insoluble humus was generated in the mixture of BQ and AA. These results suggest that the presence of AA might interfere with photosynthesis and respiration through the interactions with quinones.
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Affiliation(s)
- Jiyuan Jin
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Zhihao Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Xiaojie Song
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Bingdang Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Guoyang Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Shujuan Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
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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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Chen Z, Jin J, Song X, Zhang G, Zhang S. Redox Conversion of Arsenite and Nitrate in the UV/Quinone Systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:10011-10018. [PMID: 30063337 DOI: 10.1021/acs.est.8b03538] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Whether superoxide radical anion (O2•-) was a key reactive species in the oxidation of arsenite (As(III)) in photochemical processes has long been a controversial issue. With hydroquinone (BQH2) and 1,4-benzoquinone (BQ) as redox mediators, the photochemical oxidation of As(III) and reduction of nitrate (NO3-) was carefully investigated. O2•-, singlet oxygen (1O2), H2O2, and semiquinone radical (BQH•) were all possible reactive species in the irradiated system. However, since the formation of As(IV) is a necessary step in the oxidation of As(III), taking the standard reduction potentials into account, the reactions between the above species and As(III) were thermodynamically unfavorable. On the basis of radical scavenging experiments, hydroxyl radical (•OH) was proved as the key species that led to the oxidation of As(III) in the UV/BQH2 system. It should be noted that the •OH radicals were generated from the photolysis of H2O2, which came from the disproportionation of O2•- and the reaction of O2•- with BQH2. Both the photoejected eaq- from 1(BQH2)* and the direct electron transfer with 3(BQH2)* contributed to the reduction of NO3- in the UV/BQH2 process. No synergistic effect was observed in the redox conversion of As(III) and NO3-, further demonstrating that the role of BQH• was negligible in the studied systems. The results here are helpful for a better understanding of the photochemical behaviors of quinones in the aquatic environment.
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Affiliation(s)
- Zhihao Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , 163 Xianlin Avenue , Nanjing , 210023 , China
| | - Jiyuan Jin
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , 163 Xianlin Avenue , Nanjing , 210023 , China
| | - Xiaojie Song
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , 163 Xianlin Avenue , Nanjing , 210023 , China
| | - Guoyang Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , 163 Xianlin Avenue , Nanjing , 210023 , China
| | - Shujuan Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , 163 Xianlin Avenue , Nanjing , 210023 , China
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18
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Chen PY, Chu XN, Liu L, Hu JY. Effect of salinity on medium- and low-pressure UV disinfection of Vibrio cholerae. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2018; 77:655-661. [PMID: 29431710 DOI: 10.2166/wst.2017.520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The problem of biological invasions attributed to ballast water release is an ongoing problem that threatens ecosystems and human health. Ultraviolet (UV) radiation has been increasingly used for ballast water treatment mainly due to the advantages of short contact time and minimized harmful disinfection by products. In this study, the impact of salinity on the inactivation of Vibrio cholerae (NCTC 7253) was examined, and comparison of inactivation level and disinfection kinetics after medium-pressure (MP) (1 kW) and low-pressure (LP) (10 W) UV irradiation was made. MP UV exposure resulted in higher inactivation efficacy against V. cholerae than LP UV exposure especially at lower UV doses (≤3 mJ cm-2) and salinity had a negative impact on both MP and LP UV disinfection, especially at higher UV doses (≥3 mJ cm-2 for MP and ≥4 mJ cm-2 for LP). To understand the mechanisms of salinity effect on V. cholerae, the enzyme-linked immunosorbent assay (ELISA) was employed to determine the number of cyclobutane pyrimidine dimers (CPDs), one major type of DNA damage. No significant effects of salinity were found at the CPDs level except for 3% artificial seawater after LP UV exposure case. It is imperative that site-specific conditions of salinity be taken into account in the design of UV reactors to treat V. cholerae and other species.
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Affiliation(s)
- P Y Chen
- Department of Civil & Environmental Engineering, National University of Singapore, Singapore 117576, Singapore E-mail:
| | - X N Chu
- Department of Civil & Environmental Engineering, National University of Singapore, Singapore 117576, Singapore E-mail:
| | - L Liu
- Department of Civil & Environmental Engineering, National University of Singapore, Singapore 117576, Singapore E-mail:
| | - J Y Hu
- Department of Civil & Environmental Engineering, National University of Singapore, Singapore 117576, Singapore E-mail:
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A Model Study of the Photochemical Fate of As(III) in Paddy-Water. Molecules 2017; 22:molecules22030445. [PMID: 28287457 PMCID: PMC6155196 DOI: 10.3390/molecules22030445] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 03/03/2017] [Accepted: 03/06/2017] [Indexed: 12/04/2022] Open
Abstract
The APEX (Aqueous Photochemistry of Environmentally-occurring Xenobiotics) software previously developed by one of us was used to model the photochemistry of As(III) in paddy-field water, allowing a comparison with biotic processes. The model included key paddy-water variables, such as the shielding effect of the rice canopy on incident sunlight and its monthly variations, water pH, and the photochemical parameters of the chromophoric dissolved organic matter (CDOM) occurring in paddy fields. The half-life times (t1/2) of As(III) photooxidation to As(V) would be ~20–30 days in May. In contrast, the photochemical oxidation of As(III) would be much slower in June and July due to rice-canopy shading of radiation because of plant growth, despite higher sunlight irradiance. At pH < 8 the photooxidation of As(III) would mainly be accounted for by reaction with transient species produced by irradiated CDOM (here represented by the excited triplet states 3CDOM*, neglecting the possibly more important reactions with poorly known species such as the phenoxy radicals) and, to a lesser extent, with the hydroxyl radicals (HO•). However, the carbonate radicals (CO3•−) could be key photooxidants at pH > 8.5 provided that the paddy-water 3CDOM* is sufficiently reactive toward the oxidation of CO32−. In particular, if paddy-water 3CDOM* oxidizes the carbonate anion with a second-order reaction rate constant near (or higher than) 106 M−1·s−1, the photooxidation of As(III) could be quite fast at pH > 8.5. Such pH conditions can be produced by elevated photosynthetic activity that consumes dissolved CO2.
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Carena L, Minella M, Barsotti F, Brigante M, Milan M, Ferrero A, Berto S, Minero C, Vione D. Phototransformation of the Herbicide Propanil in Paddy Field Water. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:2695-2704. [PMID: 28145687 DOI: 10.1021/acs.est.6b05053] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
When irradiated in paddy-field water, propanil (PRP) undergoes photodegradation by direct photolysis, by reactions with •OH and CO3•-, and possibly also with the triplet states of chromophoric dissolved organic matter. Irradiation also inhibits the nonphotochemical (probably biological) degradation of PRP. The dark- and light-induced pathways can be easily distinguished because 3,4-dichloroaniline (34DCA, a transformation intermediate of considerable environmental concern) is produced with almost 100% yield in the dark but not at all through photochemical pathways. This issue allows an easy assessment of the dark process(es) under irradiation. In the natural environment, we expect PRP photodegradation to be important only in the presence of elevated nitrate and/or nitrite levels, e.g., [NO3-] approaching 1 mmol L-1 (corresponding to approximately 60 mg L-1). Under these circumstances, •OH and CO3•- would play a major role in PRP phototransformation. Because flooded paddy fields are efficient denitrification bioreactors that can achieve decontamination of nitrate-rich water used for irrigation, irrigation with such water would both enhance PRP photodegradation and divert PRP dissipation processes away from the production of 34DCA, at least in the daylight hours.
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Affiliation(s)
- Luca Carena
- Dipartimento di Chimica, Università di Torino , Via Pietro Giuria 5, 10125 Torino, Italy
| | - Marco Minella
- Dipartimento di Chimica, Università di Torino , Via Pietro Giuria 5, 10125 Torino, Italy
| | - Francesco Barsotti
- Dipartimento di Chimica, Università di Torino , Via Pietro Giuria 5, 10125 Torino, Italy
| | - Marcello Brigante
- Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, & CNRS, UMR 6296, ICCF, BP 80026 , F-63177 Aubière, France
| | - Marco Milan
- Dipartimento di Scienze Agrarie, Forestali e Alimentari, Università di Torino , Largo Paolo Braccini 2, 10095 Grugliasco (TO), ITALY
| | - Aldo Ferrero
- Dipartimento di Scienze Agrarie, Forestali e Alimentari, Università di Torino , Largo Paolo Braccini 2, 10095 Grugliasco (TO), ITALY
| | - Silvia Berto
- Dipartimento di Chimica, Università di Torino , Via Pietro Giuria 5, 10125 Torino, Italy
| | - Claudio Minero
- Dipartimento di Chimica, Università di Torino , Via Pietro Giuria 5, 10125 Torino, Italy
| | - Davide Vione
- Dipartimento di Chimica, Università di Torino , Via Pietro Giuria 5, 10125 Torino, Italy
- Università di Torino , Centro Interdipartimentale NatRisk, Largo Paolo Braccini 2, 10095 Grugliasco (TO), Italy
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21
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Liu L, Chu X, Chen P, Xiao Y, Hu J. Effects of water quality on inactivation and repair of Microcystis viridis and Tetraselmis suecica following medium-pressure UV irradiation. CHEMOSPHERE 2016; 163:209-216. [PMID: 27529385 DOI: 10.1016/j.chemosphere.2016.08.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 06/14/2016] [Accepted: 08/04/2016] [Indexed: 06/06/2023]
Abstract
The transfer of invasive organisms by ballast-water discharge has become a growing concern. UV treatment has become an attractive ballast water treatment technology due to its effectiveness, no harmful disinfection byproducts and easiness to handle. Two robust algae strains Microcystis viridis and Tetraselmis suecica were selected as indicator organisms to determine efficiency of medium-pressure (MP) UV-treatment on ballast water. Inactivation and potential repair of these two algae strains following MP UV irradiation were assessed under various turbidity, total organic carbon (TOC) and salinity conditions. The investigated range of UV doses was from 25 to 500 mJ/cm(2). For M. viridis, results indicated that disinfection efficiency was negatively correlated with all of these three factors at low doses (25-200 mJ/cm(2)). Photoreactivation and dark repair were promoted at high TOC levels (6-15 mg/L) with about 6-25% higher repair levels compared with those in distilled water, whereas no significant impacts were identified for turbidity and salinity on both of the photoreactivation and dark repair. For T. suecica, increased turbidity and TOC levels both hindered the performance of UV irradiation at high doses (200-500 mJ/cm(2)). Suppressive effects on photoreactivation and dark repair were consistently observed with changes of all of the three factors. In conclusion, generally these three factors resulted in repressive effects on UV disinfection efficiency, and TOC played a more significant role in the levels of reactivation than the other two. The responses of T. suecica to these three factors were more sensitive than M. viridis.
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Affiliation(s)
- Lei Liu
- Department of Civil & Environmental Engineering, National University of Singapore, Singapore 117576, Singapore; School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Xiaona Chu
- Department of Civil & Environmental Engineering, National University of Singapore, Singapore 117576, Singapore
| | - Pengyu Chen
- Department of Civil & Environmental Engineering, National University of Singapore, Singapore 117576, Singapore; School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Yan Xiao
- Department of Civil & Environmental Engineering, National University of Singapore, Singapore 117576, Singapore
| | - Jiangyong Hu
- Department of Civil & Environmental Engineering, National University of Singapore, Singapore 117576, Singapore.
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22
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Ding W, Romanova TE, Pozdnyakov IP, Salomatova VA, Parkhats MV, Dzhagarov BM, Glebov EM, Wu F, Shuvaeva OV. Photooxidation of arsenic(III) in the presence of fulvic acid. MENDELEEV COMMUNICATIONS 2016. [DOI: 10.1016/j.mencom.2016.05.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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23
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Chen PY, Chu XN, Liu L, Hu JY. Effects of salinity and temperature on inactivation and repair potential of Enterococcus faecalis
following medium- and low-pressure ultraviolet irradiation. J Appl Microbiol 2016; 120:816-25. [DOI: 10.1111/jam.13026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 10/19/2015] [Accepted: 10/30/2015] [Indexed: 11/29/2022]
Affiliation(s)
- P.-Y. Chen
- Department of Civil and Environmental Engineering; National University of Singapore; Singapore Singapore
| | - X.-N. Chu
- Department of Civil and Environmental Engineering; National University of Singapore; Singapore Singapore
| | - L. Liu
- Department of Civil and Environmental Engineering; National University of Singapore; Singapore Singapore
| | - J.-Y. Hu
- Department of Civil and Environmental Engineering; National University of Singapore; Singapore Singapore
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24
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Zou JP, Wu DD, Bao SK, Luo J, Luo XB, Lei SL, Liu HL, Du HM, Luo SL, Au CT, Suib SL. Hydrogen Evolution from Water Coupled with the Oxidation of As(III) in a Photocatalytic System. ACS APPLIED MATERIALS & INTERFACES 2015; 7:28429-28437. [PMID: 26650610 DOI: 10.1021/acsami.5b09255] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A series of heterostructured CdS/Sr2(Nb17/18Zn1/18)2O7-δ composites with excellent photocatalytic ability for simultaneous hydrogen evolution and As(III) oxidation under simulated sunlight were synthesized and characterized. Among them, 30% CdS/Sr2(Nb17/18Zn1/18)2O7-δ (30CSNZO) has the highest in activity, exhibiting a H2 production rate of 1669.1 μmol·h(-1)·g(-1) that is higher than that of many photocatalysts recently reported in the literature. At pH 9, As(III) is completely oxidized to As(V) over 30CSNZO in 30 min of irradiation of simulated sunlight. In the photocatalytic system, H2 production rate decreases with the increase of As(III) concentration, and the recycle experiments show that 30CSNZO exhibits excellent stability, durability, and recyclability for photocatalytic hydrogen evolution and As(III) oxidation. We propose a mechanism in which superoxide radical (·O2(-)) is the active species for As(III) oxidation and the oxidation of As(III) has an effect on hydrogen evolution. For the first time, it is demonstrated that simultaneous hydrogen evolution and arsenite oxidation is possible in a photocatalytic system.
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Affiliation(s)
- Jian-Ping Zou
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University , Nanchang, Jiangxi 100044, PR China
| | - Dan-Dan Wu
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University , Nanchang, Jiangxi 100044, PR China
| | - Shao-Kui Bao
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University , Nanchang, Jiangxi 100044, PR China
| | - Jinming Luo
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100864, PR China
| | - Xu-Biao Luo
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University , Nanchang, Jiangxi 100044, PR China
| | - Si-Liang Lei
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University , Nanchang, Jiangxi 100044, PR China
| | - Hui-Long Liu
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University , Nanchang, Jiangxi 100044, PR China
| | - Hong-Mei Du
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University , Nanchang, Jiangxi 100044, PR China
| | - Sheng-Lian Luo
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University , Nanchang, Jiangxi 100044, PR China
| | - Chak-Tong Au
- State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University , Kowloon Tong, Hong Kong 999077, PR China
| | - Steven L Suib
- Department of Chemistry, University of Connecticut , Storrs, Connecticut 06269, United States
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25
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Ding W, Wang Y, Yu Y, Zhang X, Li J, Wu F. Photooxidation of arsenic(III) to arsenic(V) on the surface of kaolinite clay. J Environ Sci (China) 2015; 36:29-37. [PMID: 26456603 DOI: 10.1016/j.jes.2015.03.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/14/2015] [Accepted: 03/12/2015] [Indexed: 05/24/2023]
Abstract
As one of the most toxic heavy metals, the oxidation of inorganic arsenic has drawn great attention among environmental scientists. However, little has been reported on the solar photochemical behavior of arsenic species on top-soil. In the present work, the influencing factors (pH, relative humidity (RH), humic acid (HA), trisodium citrate, and additional iron ions) and the contributions of reactive oxygen species (ROS, mainly HO and HO2/O2(-)) to photooxidation of As(III) to As(V) on kaolinite surfaces under UV irradiation (λ=365nm) were investigated. Results showed that lower pH facilitated photooxidation, and the photooxidation efficiency increased with the increase of RH and trisodium citrate. Promotion or inhibition of As(III) photooxidation by HA was observed at low or high dosages, respectively. Additional iron ions greatly promoted the photooxidation, but excessive amounts of Fe(2+) competed with As(III) for oxidation by ROS. Experiments on scavengers indicated that the HO radical was the predominant oxidant in this system. Experiments on actual soil surfaces proved the occurrence of As(III) photooxidation in real topsoil. This work demonstrates that the photooxidation process of As(III) on the soil surface should be taken into account when studying the fate of arsenic in natural soil newly polluted with acidic wastewater containing As(III).
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Affiliation(s)
- Wei Ding
- Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, Wuhan 430079, China.
| | - Yajie Wang
- Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, Wuhan 430079, China
| | - Yingtan Yu
- Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, Wuhan 430079, China
| | - Xiangzhi Zhang
- Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.
| | - Jinjun Li
- Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, Wuhan 430079, China
| | - Feng Wu
- Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, Wuhan 430079, China.
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26
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Bodhipaksha LC, Sharpless CM, Chin YP, Sander M, Langston WK, MacKay AA. Triplet photochemistry of effluent and natural organic matter in whole water and isolates from effluent-receiving rivers. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:3453-63. [PMID: 25671497 DOI: 10.1021/es505081w] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Effluent organic matter (EfOM), contained in treated municipal wastewater, differs in composition from naturally occurring dissolved organic matter (DOM). The presence of EfOM may thus alter the photochemical production of reactive intermediates in rivers that receive measurable contributions of treated municipal wastewater. Quantum yield coefficients for excited triplet-state OM (3OM*) and apparent quantum yields for singlet oxygen (1O2) were measured for both whole water samples and OM isolated by solid phase extraction from whole water samples collected upstream and downstream of municipal wastewater treatment plant discharges in three rivers receiving differing effluent contributions: Hockanum R., CT (22% (v/v) effluent flow), E. Fork Little Miami R., OH (11%), and Pomperaug R., CT (6%). While only small differences in production of these reactive intermediates were observed between upstream and downstream whole water samples collected from the same river, yields of 3OM* and 1O2 varied by 30-50% between the rivers. Apparent quantum yields of 1O2 followed similar trends to those of 3OM*, consistent with 3OM* as a precursor to 1O2 formation. Higher 3OM* reactivity was observed for whole water samples than for OM isolates of the same water, suggesting differential recoveries of photoreactive moieties by solid phase extraction. 3OM* and 1O2 yields increased with increasing E2/E3 ratio (A254 nm divided by A365 nm) and decreased with increasing electron donating capacities of the samples, thus exhibiting trends also observed for reference humic and fulvic acid isolates. Mixing experiments with EfOM and DOM isolates showed evidence of quenching of triplet DOM by EfOM when measured yields were compared to theoretical yields. Together, the results suggest that effluent contributions of up to 25% (v/v) to river systems have a negligible influence on photochemical production of 3OM* and 1O2 apparently because of quenching of triplet DOM by EfOM. Furthermore, the results highlight the importance of whole water studies for quantifying in situ photoreactivity, particularly for 3OM*.
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Affiliation(s)
- Laleen C Bodhipaksha
- †Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269-3060, United States
| | - Charles M Sharpless
- ‡Department of Chemistry, University of Mary Washington, Fredericksburg, Virginia 22401, United States
| | - Yu-Ping Chin
- §School of Earth Sciences, The Ohio State University, 125 South Oval Mall, Columbus, Ohio 43210, United States
| | - Michael Sander
- ∥Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology (ETH) Zurich, CH-8092 Zurich, Switzerland
| | - William K Langston
- ‡Department of Chemistry, University of Mary Washington, Fredericksburg, Virginia 22401, United States
| | - Allison A MacKay
- †Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269-3060, United States
- ⊥Environmental Engineering Program and Center for Environmental Sciences and Engineering, University of Connecticut, 261 Glenbrook Road, Storrs, Connecticut 06269-3037, United States
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27
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Rubio D, Nebot E, Casanueva JF, Pulgarin C. Comparative effect of simulated solar light, UV, UV/H2O2 and photo-Fenton treatment (UV-Vis/H2O2/Fe2+,3+) in the Escherichia coli inactivation in artificial seawater. WATER RESEARCH 2013; 47:6367-6379. [PMID: 24035676 DOI: 10.1016/j.watres.2013.08.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 07/23/2013] [Accepted: 08/06/2013] [Indexed: 05/29/2023]
Abstract
Innovative disinfection technologies are being studied for seawater, seeking a viable alternative to chlorination. This study proposes the use of H2O2/UV254 and photo-Fenton as disinfection treatment in seawater. The irradiations were carried out using a sunlight simulator (Suntest) and a cylindrical UV reactor. The efficiency of the treatment was compared for Milli-Q water, Leman Lake water and artificial seawater. The presence of bicarbonates and organic matter was investigated in order to evaluate possible effects on the photo-Fenton disinfection treatment. The photo-Fenton treatment, employing 1 mg L(-1) Fe(2+) and 10 mg L(-1) of H2O2, led to the fastest bacterial inactivation kinetics. Using H2O2/UV254 high disinfection rates were obtained similar to those obtained with photo-Fenton under UV254 light. In Milli-Q water, the rate of inactivation for Escherichia coli was higher than in Leman Lake water and seawater due to the lack of inorganic ions affecting negatively bacteria inactivation. The presence of bicarbonate showed scavenging of the OH(•) radicals generated in the treatment of photo-Fenton and H2O2/UV254. Despite the negative effect of inorganic ions, especially HCO3(-), the disinfection treatments with AOPs in lake water and seawater improved significantly the disinfection compared to light alone (simulated sunlight and UV254). In the treatment of photo-Fenton with simulated sunlight, dissolved organic matter had a beneficial effect by increasing the rate of inactivation. This is associated with the formation of Fe(3+)-organo photosensitive complexes leading to the formation of ROS able to inactivate bacteria. This effect was not observed in the photo-Fenton with UV254. Growth of E. coli surviving in seawater was observed 24 and 48 h after treatment with UV light. However, growth of surviving bacteria was not detected after photo-Fenton with UV254 and H2O2/UV254 treatments. This study suggests H2O2/UV254 and photo-Fenton treatments for the disinfection of seawater, in spite its high concentration of salts.
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Affiliation(s)
- D Rubio
- Institute of Chemical Science and Engineering, Advanced Oxidation Processes Group (GPAO), Swiss Federal Institute of Technology (EPFL), Station 6, CH-1015 Lausanne, Switzerland; Department of Environmental Technologies, Faculty of Sea and Environmental Sciences, University of Cádiz, Av. Republica Saharaui s/n, 11510 Puerto Real, Spain
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28
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Wang Y, Xu J, Li J, Wu F. Natural montmorillonite induced photooxidation of As(III) in aqueous suspensions: roles and sources of hydroxyl and hydroperoxyl/superoxide radicals. JOURNAL OF HAZARDOUS MATERIALS 2013; 260:255-262. [PMID: 23770489 DOI: 10.1016/j.jhazmat.2013.05.028] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2013] [Revised: 05/09/2013] [Accepted: 05/15/2013] [Indexed: 06/02/2023]
Abstract
Photooxidation of arsenite(As(III)) in a suspension of natural montmorillonite under the irradiation of metal halide lamp (λ ≥ 313 nm)has been investigated. The results showed that the natural montmorillonite induced the photooxidation of As(III) by generating hydroxyl radicals (HO·) and hydroperoxyl/superoxide radicals (HO₂·/O₂⁻·). HO· which was responsible for the As(III) photooxidation. Approximately 38% of HO· was generated by the photolysis of ferric ions, and the formation of the remaining 62% was strongly dependent on the HO₂·/O₂⁻·. The presence of free ironions (Fe(2+) and Fe(3+)), made significant contributions to the photogeneration of these reactive oxygen species (ROS). The photooxidation of As(III) in natural montmorillonite suspensions was greatly influenced by the pH values. The photooxidation of As(III) by natural montmorillonite followed the Langmuir-Hinshelwood equation. In addition, the photooxidation of As(III) could be enhanced by the addition of humic acid. This work demonstrates that photooxidation may be an important environmental process for the oxidation of As(III) and may be a way to remove As(III) from acidic surface water containing iron-bearing clay minerals.
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Affiliation(s)
- Yajie Wang
- Department of Environmental Science, Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, 430079, PR China
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29
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Ryu J, Monllor-Satoca D, Kim DH, Yeo J, Choi W. Photooxidation of arsenite under 254 nm irradiation with a quantum yield higher than unity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:9381-9387. [PMID: 23879475 DOI: 10.1021/es402011g] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Arsenite (As(III)) in water was demonstrated to be efficiently oxidized to arsenate (As(V)) under 254 nm UV irradiation without needing any chemical reagents. Although the molar absorption coefficient of As(III) at 254 nm is very low (2.49 ± 0.1 M(-1)cm(-1)), the photooxidation proceeded with a quantum yield over 1.0, which implies a chain of propagating oxidation cycles. The rate of As(III) photooxidation was highly enhanced in the presence of dissolved oxygen, which can be ascribed to its dual role as an electron acceptor of photoexcited As(III) and a precursor of oxidizing radicals. The in situ production of H2O2 was observed during the photooxidation of As(III) and its subsequent photolysis under UV irradiation produced OH radicals. The addition of tert-butyl alcohol as OH radical scavenger significantly reduced (but not completely inhibited) the oxidation rate, which indicates that OH radicals as well as superoxide serve as an oxidant of As(III). Superoxide, H2O2, and OH radicals were all in situ generated from the irradiated solution of As(III) in the presence of dissolved O2 and their subsequent reactions with As(III) induce the regeneration of some oxidants, which makes the overall quantum yield higher than 1. The homogeneous photolysis of arsenite under 254 nm irradiation can be also proposed as a new method of generating OH radicals.
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Affiliation(s)
- Jungho Ryu
- Mineral Resources Research Division, Korea Institute of Geoscience and Mineral Resources, Daejeon 305-350, Korea
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30
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Wang Y, Xu J, Zhao Y, Zhang L, Xiao M, Wu F. Photooxidation of arsenite by natural goethite in suspended solution. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2013; 20:31-38. [PMID: 22806352 DOI: 10.1007/s11356-012-1079-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 07/05/2012] [Indexed: 06/01/2023]
Abstract
Iron and arsenic have been found to coexist in a water environment and the fate of arsenite in the aquatic system is influenced by iron. Goethite is a form of iron hydroxide, which is commonly found in sediments. In previous studies, we have used iron complexes to degrade organic pollutants. Results have shown that some organic pollutants could be totally degraded by iron complexes and our work indicated that iron might cause conversion of arsenic when irradiated. This work attempts to investigate the conversion of arsenite [As(III)] using natural goethite, as the iron source, to quantify the effect of various factors on photooxidation. We also consider the possible mechanism for photooxidation of As(III) using a suspension of natural goethite. The As(III) concentration variation under illumination was compared with the one in the dark to quantify the contribution of light to As(III) oxidation to As(V) in goethite suspended solution. The experiments under N(2) and air atmosphere confirmed the participation of dissolved oxygen. The photooxidation efficiency of As(III) under different conditions was compared to determine the effect of different environmental factors such as pH value, goethite concentration, and humic acid concentration on the photooxidation reaction. In the solution containing 100 μg L(-1) arsenite and 0.1 g L(-1) suspended goethite at pH 3.0, nearly 80 % of As(III) was photooxidized after irradiation by a 250-W metal halogen lamp (λ ≥ 313 nm) after 6 h. The effects of initial pH and goethite concentration and humic acid concentration were all examined. The results show that the greatest efficiency of photooxidation of As(III) was at pH 3.0. The extent of photooxidation decreased with increasing goethite concentration and fell sharply in the presence of humic acid under the conditions in this work. Although about 80 % of As(III) was photooxidized after irradiation by a 250-W halogen lamp at pH 3.0 in the presence of goethite suspension, photooxidation was also affected by factors such as pH, concentration of goethite, and presence of humic acid. The scavenger experiments showed that the HO• radical and photogenerated hole are the predominant oxidants in this system responsible for 87.1 % oxidation of As(III), while HO (2)(•) /O(2)(•-) is responsible for 12.9 % oxidation of As(III).
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Affiliation(s)
- Yajie Wang
- Department of Environmental Science, Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, Wuhan 430079, People's Republic of China
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31
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De la Cruz N, Giménez J, Esplugas S, Grandjean D, de Alencastro LF, Pulgarín C. Degradation of 32 emergent contaminants by UV and neutral photo-fenton in domestic wastewater effluent previously treated by activated sludge. WATER RESEARCH 2012; 46:1947-57. [PMID: 22305640 DOI: 10.1016/j.watres.2012.01.014] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 01/12/2012] [Accepted: 01/16/2012] [Indexed: 05/22/2023]
Abstract
This study focuses on the removal of 32 selected micropollutants (pharmaceuticals, corrosion inhibitors and biocides/pesticides) found in an effluent coming from a municipal wastewater treatment plant (MWTP) based on activated sludge. Dissolved organic matter was present, with an initial total organic carbon of 15.9 mg L(-1), and a real global quantity of micropollutants of 29.5 μg L(-1). The treatments tested on the micropollutants removal were: UV-light emitting at 254 nm (UV(254)) alone, dark Fenton (Fe(2+,3+)/H(2)O(2)) and photo-Fenton (Fe(2+,3+)/H(2)O(2)/light). Different irradiation sources were used for the photo-Fenton experiences: UV(254) and simulated sunlight. Iron and H(2)O(2) concentrations were also changed in photo-Fenton experiences in order to evaluate its influence on the degradation. All the experiments were developed at natural pH, near neutral. Photo-Fenton treatments employing UV(254), 50 mg L(-1) of H(2)O(2), with and without adding iron (5 mg L(-1) of Fe(2+) added or 1.48 mg L(-1) of total iron already present) gave the best results. Global percentages of micropollutants removal achieved were 98 and a 97% respectively, after 30 min of treatments. As the H(2)O(2) concentration increased (10, 25 and 50 mg L(-1)), best degradations were observed. UV(254), Fenton, and photo-Fenton under simulated sunlight gave less promising results with lower percentages of removal. The highlight of this paper is to point out the possibility of the micropollutants degradation in spite the presence of DOM in much higher concentrations.
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Affiliation(s)
- N De la Cruz
- Institut des Sciences et Ingénierie Chimiques, GGEC, EPFL, Bât. CH, 1015 Lausanne, Switzerland
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32
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Fritzsche A, Rennert T, Totsche KU. Arsenic strongly associates with ferrihydrite colloids formed in a soil effluent. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2011; 159:1398-1405. [PMID: 21310516 DOI: 10.1016/j.envpol.2011.01.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 12/22/2010] [Accepted: 01/03/2011] [Indexed: 05/30/2023]
Abstract
Arsenic mobility may increase in liquid phase due to association with colloidal Fe oxides. We studied the association of As with Fe oxide colloids in the effluent from water-saturated soil columns run under anoxic conditions. Upon exfiltration, the solutions, which contained Fe2+, were re-aerated and ferrihydrite colloids precipitated. The entire amount of effluent As was associated with the ferrihydrite colloids, although PO4(3-), SiO4(4-), CO3(2-) and dissolved organic matter were present in the effluent during ferrihydrite colloid formation. Furthermore, no subsequent release of As from the ferrihydrite colloids was observed despite the presence of these (in)organic species known to compete with As for adsorption on Fe oxides. Arsenic was bound via inner-sphere complexation on the ferrihydrite surface. FTIR spectroscopy also revealed adsorption of PO4(3-) and polymerized silica. However, these species could not impede the quantitative association of As with colloidal ferrihydrite in the soil effluents.
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Affiliation(s)
- Andreas Fritzsche
- LS Hydrogeologie, Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, D-07749 Jena, Germany.
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Litter MI, Morgada ME, Bundschuh J. Possible treatments for arsenic removal in Latin American waters for human consumption. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2010; 158:1105-1118. [PMID: 20189697 DOI: 10.1016/j.envpol.2010.01.028] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2009] [Revised: 01/25/2010] [Accepted: 01/31/2010] [Indexed: 05/28/2023]
Abstract
Considering the toxic effects of arsenic, the World Health Organization recommends a maximum concentration of 10 microg L(-1) of arsenic in drinking water. Latin American populations present severe health problems due to consumption of waters with high arsenic contents. The physicochemical properties of surface and groundwaters are different from those of other more studied regions of the planet, and the problem is still publicly unknown. Methods for arsenic removal suitable to be applied in Latin American waters are here summarized and commented. Conventional technologies (oxidation, coagulation-coprecipitation, adsorption, reverse osmosis, use of ion exchangers) are described, but emphasis is made in emergent decentralized economical methods as the use of inexpensive natural adsorbents, solar light technologies or biological treatments, as essential to palliate the situation in poor, isolated and dispersed populations of Latin American regions.
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Affiliation(s)
- Marta I Litter
- Gerencia Química, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, CP 1650, San Martín, Prov. de Buenos Aires, Argentina.
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Tsimas ES, Tyrovola K, Xekoukoulotakis NP, Nikolaidis NP, Diamadopoulos E, Mantzavinos D. Simultaneous photocatalytic oxidation of As(III) and humic acid in aqueous TiO2 suspensions. JOURNAL OF HAZARDOUS MATERIALS 2009; 169:376-85. [PMID: 19395168 DOI: 10.1016/j.jhazmat.2009.03.107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2008] [Revised: 03/16/2009] [Accepted: 03/23/2009] [Indexed: 05/02/2023]
Abstract
The simultaneous photocatalytic oxidation of As(III) and humic acid (HA) in aqueous Degussa P25 TiO(2) suspensions was investigated. Preliminary photocatalytic studies of the binary As(III)/TiO(2) and HA/TiO(2) systems showed that As(III) was oxidized more rapidly than HA and the extent of photocatalytic oxidation of each individual component (i.e. As(III) or HA) increased with decreasing its initial concentration and/or increasing catalyst loading. The simultaneous photocatalytic oxidation of As(III) and HA in the ternary As(III)/HA/TiO(2) system showed that both As(III) and HA oxidation was reduced in the ternary system compared to the corresponding binary systems. The effect of operating conditions in the ternary system, such as initial As(III), HA and TiO(2) concentrations (in the range 3-20mg/L, 10-100mg/L and 50-250 mg/L respectively), initial solution pH (3.6-6.7) and reaction time (10-30 min), on photocatalytic As(III) and HA oxidation was assessed implementing a two-level factorial experimental design methodology. Seven and ten factors were found statistically important in the case of photocatalytic As(III) and HA oxidation respectively. Based on these statistically significant factors, a first order polynomial model describing As(III) and HA photocatalytic oxidation was constructed and a very good agreement was obtained between the experimental values and those predicted by the model, while the observed differences may be readily explained as random noise.
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Affiliation(s)
- Emmanuil S Tsimas
- Department of Environmental Engineering, Technical University of Crete, GR-73100 Chania, Greece
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35
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Yoon SH, Lee JH, Oh S, Yang JE. Photochemical oxidation of As(III) by vacuum-UV lamp irradiation. WATER RESEARCH 2008; 42:3455-3463. [PMID: 18514252 DOI: 10.1016/j.watres.2008.04.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Revised: 03/18/2008] [Accepted: 04/01/2008] [Indexed: 05/26/2023]
Abstract
In this study, vacuum-UV (VUV) lamp irradiation emitting both 185 and 254 nm lights has been investigated as a new oxidation method for As(III). Laboratory scale experiments were conducted with a batch reactor and a commercial VUV lamp. Under the experimental conditions of this study, the employed VUV lamp showed a higher performance for As(III) oxidation compared to other photochemical oxidation methods (UV-C/H(2)O(2), UV-A/Fe(III)/H(2)O(2), and UV-A/TiO2). The VUV lamp oxidized 100 microM As(III) almost completely in 10 min, and the reaction occurred mainly due to OH radicals which were produced by photo-splitting of water (H(2)O+hv (lambda=185 nm)-->OH.+H.). There was a little possibility that photo-generated H(2)O(2) acted as a minor oxidant of As(III) at alkaline pHs. The effects of Fe(III), H(2)O(2), and humic acid (HA) on the As(III) oxidation by VUV lamp irradiation were investigated. While Fe(III) and H(2)O(2) increased the As(III) oxidation efficiency, HA did not cause a significant effect. The employed VUV lamp was effective for oxidizing As(III) not only in a Milli-Q water but also in a real natural water, without significant decrease in the oxidation efficiency. Since the formed As(V) should be removed from water, activated alumina (AA) was added as an adsorbent during the As(III) oxidation by VUV lamp irradiation. The combined use of VUV lamp irradiation and AA was much more effective for the removal of total arsenic (As(tot)=As(III)+As(V)) than the single use of AA. The As(tot) removal seemed to occur as a result of the pre-oxidation of As(III) and the subsequent adsorption of As(V) on AA. Alternatively, the combination of VUV lamp irradiation and coagulation/precipitation with FeCl(3) was also an effective removal strategy for As(tot). This study shows that vacuum-UV (VUV) lamp irradiation emitting both 185 and 254 nm lights is a powerful and environmentally friendly method for As(III) oxidation which does not require additional oxidants or catalysts. The As(III) oxidation by VUV lamp irradiation was tested not only in a batch reactor but also in a flow-through quartz reactor. The As(III) oxidation rate became much faster in the latter reactor.
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Affiliation(s)
- Sung-Hwan Yoon
- Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 1-Oryong-Dong, Buk-Gu, Gwangju, Republic of Korea.
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Barringer JL, Wilson TP, Szabo Z, Bonin JL, Fischer JM, Smith NP. Diurnal variations in, and influences on, concentrations of particulate and dissolved arsenic and metals in the mildly alkaline Wallkill River, New Jersey, USA. ACTA ACUST UNITED AC 2007. [DOI: 10.1007/s00254-007-0708-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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