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Jasemizad T, Padhye LP. Photodegradation and adsorption of hexazinone in aqueous solutions: removal efficiencies, kinetics, and mechanisms. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:48330-48339. [PMID: 35190983 PMCID: PMC9252970 DOI: 10.1007/s11356-022-19205-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 02/09/2022] [Indexed: 06/14/2023]
Abstract
Hexazinone, a globally applied broad-spectrum triazine herbicide, has not been mechanistically investigated previously under advanced oxidation processes (AOPs) and adsorption on activated carbon. In this study, its fate during UV-based oxidation with/without hydrogen peroxide (H2O2) and adsorption on coconut shell-based granular activated carbon (CSGAC) in water matrices was investigated. A comparison between various irradiation sources (visible, UVA, UVB, and UVC) revealed the highest degradation rate under UVC. More than 98% degradation of hexazinone was observed under 3 J cm-2 UVC fluence in the presence of 0.5 mM H2O2 at pH 7. Moreover, the degradation rate enhanced significantly with an increase in the initial dosage of H2O2, UV fluence, and contact time in the UV/H2O2 process. The rate of degradation was lower using secondary effluent than that of Milli-Q water due to the presence of dissolved organics in wastewater. However, the reactions in both matrices obeyed pseudo-first-order kinetics. The effect of different scavengers, including methanol, potassium iodide (KI), and tert-butyl alcohol (TBA), showed that hydroxyl radicals (•OH) played a dominant role in hexazinone degradation in the UV/H2O2 process. Hexazinone was effectively adsorbed by CSGAC through π-π electron donor-acceptor interactions between hexazinone's triazine ring and CSGAC's surface functional groups. The isotherm and kinetic studies showed that the adsorption followed the Freundlich model and pseudo-second-order reaction, respectively, suggesting chemisorption. This study provided mechanistic insights on the removal of hexazinone at the tertiary stage of wastewater treatment or the advanced treatment of wastewater reuse.
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Affiliation(s)
- Tahereh Jasemizad
- Department of Civil and Environmental Engineering, The University of Auckland, Auckland, New Zealand
| | - Lokesh P Padhye
- Department of Civil and Environmental Engineering, The University of Auckland, Auckland, New Zealand.
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2
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Yang T, Wu S, Liu C, Liu Y, Zhang H, Cheng H, Wang L, Guo L, Li Y, Liu M, Ma J. Efficient Degradation of Organoarsenic by UV/Chlorine Treatment: Kinetics, Mechanism, Enhanced Arsenic Removal, and Cytotoxicity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:2037-2047. [PMID: 33435681 DOI: 10.1021/acs.est.0c05084] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Roxarsone (ROX) has been widely used as an organoarsenic additive in animal feeding operations and poses a risk to the environment. Here, we first report the efficient degradation of ROX by UV/chlorine, where the kinetics, removal of total arsenic (As), and cytotoxicity were investigated. The kinetics study presented that reactive chlorine species (RCS) and HO• were the dominant species to react with ROX. Furthermore, the degradation rate of ROX can reach the maximum value at pH 7.5 due to the formation of more RCS. The degradation of ROX was affected by the amount of chlorine, pH, and water matrix. Through product analysis and Gauss theoretical calculation, two possible ROX degradation pathways were proposed. The free radicals attacked the As-C bond of ROX and resulted in releasing arsenate (As(V)). It was the reason that for an enhancement of the removal of total As by ferrous appeared after UV/chlorine, and over 98% of the total As was removed. In addition, cytotoxicity studies indicated that the cytotoxicity significantly enhanced during the degradation of ROX by UV/chlorine. However, by combination of UV/chlorine and adsorption, cytotoxicity can be greatly eliminated, probably due to the removal of As(V) and chlorinated products. These results further demonstrated that UV/chlorine treatment could be an effective method for the control of the potential environmental risks posed by organoarsenic.
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Affiliation(s)
- Tao Yang
- School of Biotechnology and Health Science, Wuyi University, Jiangmen 529020, China
| | - Sisi Wu
- School of Biotechnology and Health Science, Wuyi University, Jiangmen 529020, China
| | - Chunping Liu
- Department of Cardiovascular Medicine, Guangdong Hospital of Traditional Chinese Medicine, Guangzhou 510120, China
| | - Yulei Liu
- Technology R&D Center for Environmental Engineering, Dongguan University of Technology, Dongguan 523808, China
| | - Haochen Zhang
- State Key Laboratory of Urban Water Resource and Environment, School of Environmental, Harbin Institute of Technology, Harbin 150090, China
| | - Haijun Cheng
- State Key Laboratory of Urban Water Resource and Environment, School of Environmental, Harbin Institute of Technology, Harbin 150090, China
| | - Lu Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environmental, Harbin Institute of Technology, Harbin 150090, China
| | - Lin Guo
- School of Biotechnology and Health Science, Wuyi University, Jiangmen 529020, China
| | - Yuying Li
- School of Biotechnology and Health Science, Wuyi University, Jiangmen 529020, China
| | - Minchao Liu
- School of Biotechnology and Health Science, Wuyi University, Jiangmen 529020, China
| | - Jun Ma
- State Key Laboratory of Urban Water Resource and Environment, School of Environmental, Harbin Institute of Technology, Harbin 150090, China
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3
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Rolph CA, Jefferson B, Brookes A, Hassard F, Villa R. Achieving drinking water compliance levels for metaldehyde with an acclimated sand bioreactor. WATER RESEARCH 2020; 184:116084. [PMID: 32668301 DOI: 10.1016/j.watres.2020.116084] [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: 04/11/2019] [Revised: 06/16/2020] [Accepted: 06/17/2020] [Indexed: 06/11/2023]
Abstract
Metaldehyde removal was delivered to below the 0.1 μg L-1 regulatory concentration in a laboratory scale continuous upflow fluidised sand bioreactor that had undergone acclimation through selective enrichment for metaldehyde degradation. This is the first reported case of successful continuous flow biological treatment of metaldehyde from real drinking water sources treating environmentally realistic metaldehyde concentrations. The impact of the acclimation process was impermanent, with the duration of effective treatment directly related to the elevated concentration of metaldehyde used during the enrichment process. The efficacy of the approach was demonstrated in continuous flow columns at both laboratory and pilot scale enabling degradation rates of between 0.1 and 0.2 mg L-1 h-1. Future work needs to focus on optimisation of the sand bioreactor and the acclimation process to ensure viability and feasibility of the approach at full scale.
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Affiliation(s)
| | | | - Adam Brookes
- Anglian Water, Thorpewood House, Peterborough, UK
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4
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Aquino RVS, Barbosa AA, Ribeiro LB, Oliveira AFB, Silva JP, Azoubel PM, Rocha ORS. Degradation of leaf green food dye by heterogeneous photocatalysis with TiO2 over a polyethylene terephthalate plate. CHEMICAL PAPERS 2019. [DOI: 10.1007/s11696-019-00804-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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5
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Li Z, Yang Y, Jáuregui-Haza U, Guo Z, Campos LC. The impact of humic acid on metaldehyde adsorption onto powdered activated carbon in aqueous solution. RSC Adv 2019; 9:11-22. [PMID: 35521583 PMCID: PMC9059139 DOI: 10.1039/c8ra06802j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 12/10/2018] [Indexed: 11/21/2022] Open
Abstract
Metaldehyde has been detected in surface water and drinking water in the UK, exceeding the EU and UK standard of 0.1 μg L−1. The presence of natural organic matter (NOM) is considered to affect the removal efficiency of metaldehyde using traditional treatment methods such as adsorption by granular activated carbon. This paper selected humic acid (HA) to represent NOM and investigated the single and binary adsorption systems of metaldehyde and HA by powdered activated carbon (PAC). Metaldehyde was effectively removed by PAC in both systems. Since the percentage removal of metaldehyde was only 3% lower in the binary adsorption system, HA was therefore not considered as a significant compound competing with metaldehyde for adsorption sites on PAC. An adsorption equilibrium study and kinetic study for metaldehyde in a single system suggested that the Langmuir isotherm and the pseudo-second order kinetic model were more suitable in this case than the Freundlich isotherm and the pseudo-first order kinetic model. The two models revealed that the maximum adsorption capacity (qm) of metaldehyde by PAC was 28.3 mg g−1 and the adsorption rate (k2) was 0.16 g mg−1 min−1. The effect of pH of metaldehyde solution was also investigated in a single system. Higher percentage removal of metaldehyde was found under alkaline conditions. In contrast to metaldehyde, HA was not effectively and efficiently removed by PAC in both systems, even with higher PAC dosages and longer contact times. Hence, the microporous and mesoporous PAC was suitable for removing metaldehyde even in the binary system. Powdered activated carbon with abundant micropores and mesopores can effectively remove metaldehyde from aqueous solution in the presence of humic acid.![]()
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Affiliation(s)
- Zhuojun Li
- Department of Civil, Environmental and Geomatic Engineering
- University College London
- London WC1E 6BT
- UK
| | - Yuchen Yang
- Department of Chemistry
- University College London
- London WC1E 6BT
- UK
| | - Ulises Jáuregui-Haza
- Instituto Superior de Tecnologías y Ciencias Aplicadas (InSTEC)
- Universidad de La Habana
- La Habana
- Cuba
| | - Zhengxiao Guo
- Department of Chemistry
- University College London
- London WC1E 6BT
- UK
| | - Luiza Cintra Campos
- Department of Civil, Environmental and Geomatic Engineering
- University College London
- London WC1E 6BT
- UK
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6
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Lu X, Shao Y, Gao N, Chen J, Zhang Y, Xiang H, Guo Y. Degradation of diclofenac by UV-activated persulfate process: Kinetic studies, degradation pathways and toxicity assessments. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2017; 141:139-147. [PMID: 28340369 DOI: 10.1016/j.ecoenv.2017.03.022] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 03/13/2017] [Accepted: 03/15/2017] [Indexed: 06/06/2023]
Abstract
Diclofenac (DCF) is the frequently detected non-steroidal pharmaceuticals in the aquatic environment. In this study, the degradation of DCF was evaluated by UV-254nm activated persulfate (UV/PS). The degradation of DCF followed the pseudo first-order kinetics pattern. The degradation rate constant (kobs) was accelerated by UV/PS compared to UV alone and PS alone. Increasing the initial PS dosage or solution pH significantly enhanced the degradation efficiency. Presence of various natural water constituents had different effects on DCF degradation, with an enhancement or inhibition in the presence of inorganic anions (HCO3- or Cl-) and a significant inhibition in the presence of NOM. In addition, preliminary degradation mechanisms and major products were elucidated using LC-MS/MS. Hydroxylation, decarbonylation, ring-opening and cyclation reaction involving the attack of SO4•- or other substances, were the main degradation mechanism. TOC analyzer and Microtox bioassay were employed to evaluate the mineralization and cytotoxicity of solutions treated by UV/PS at different times, respectively. Limited elimination of TOC (32%) was observed during the mineralization of DCF. More toxic degradation products and their related intermediate species were formed, and the UV/PS process was suitable for removing the toxicity. Of note, longer degradation time may be considered for the final toxicity removal.
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Affiliation(s)
- Xian Lu
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, China
| | - Yisheng Shao
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, China; China Academy of Urban Planning & Design, Beijing, China.
| | - Naiyun Gao
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, China
| | - Juxiang Chen
- College of Architecture and Civil Engineering, Xinjiang University, Urumqi, China
| | - Yansen Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, China
| | - Huiming Xiang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, China
| | - Youluo Guo
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, China
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7
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Li Z, Kim JK, Chaudhari V, Mayadevi S, Campos LC. Degradation of metaldehyde in water by nanoparticle catalysts and powdered activated carbon. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:17861-17873. [PMID: 28612314 PMCID: PMC5533860 DOI: 10.1007/s11356-017-9249-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/09/2017] [Indexed: 06/07/2023]
Abstract
Metaldehyde, an organic pesticide widely used in the UK, has been detected in drinking water in the UK with a low concentration (<1 μg L-1) which is still above the European and UK standard requirements. This paper investigates the efficiency of four materials: powdered activated carbon (PAC) and carbon-doped titanium dioxide nanocatalyst with different concentrations of carbon (C-1.5, C-40, and C-80) for metaldehyde removal from aqueous solutions by adsorption and oxidation via photocatalysis. PAC was found to be the most effective material which showed almost over 90% removal. Adsorption data were well fitted to the Langmuir isotherm model, giving a q m (maximum/saturation adsorption capacity) value of 32.258 mg g-1 and a K L (Langmuir constant) value of 2.013 L mg-1. In terms of kinetic study, adsorption of metaldehyde by PAC fitted well with a pseudo-second-order equation, giving the adsorption rate constant k 2 value of 0.023 g mg-1 min-1, implying rapid adsorption. The nanocatalysts were much less effective in oxidising metaldehyde than PAC with the same metaldehyde concentration and 0.2 g L-1 loading concentration of materials under UV light; the maximum removal achieved by carbon-doped titanium dioxide (C-1.5) nanocatalyst was around 15% for a 7.5 ppm metaldehyde solution. Graphical abstract ᅟ.
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Affiliation(s)
- Zhuojun Li
- Department of Civil, Environmental and Geomatic Engineering, University College London, Gower Street, London, WC1E 6BT UK
| | - Jong Kyu Kim
- Kyungnam University, Gyeongsangnam-do Massanhappo-gu South Gyeongsang Daehakro 7, Changwon, South Korea
| | - Vrushali Chaudhari
- Chemical Engineering & Process Development Division, CSIR-National Chemical Laboratory, Pune, Maharashtra 411 008 India
| | - Suseeladevi Mayadevi
- Chemical Engineering & Process Development Division, CSIR-National Chemical Laboratory, Pune, Maharashtra 411 008 India
| | - Luiza C. Campos
- Department of Civil, Environmental and Geomatic Engineering, University College London, Gower Street, London, WC1E 6BT UK
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8
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Boutiti A, Zouaghi R, Bendjabeur SE, Guittonneau S, Sehili T. Photodegradation of 1-hexyl-3-methylimidazolium by UV/H2O2 and UV/TiO2: Influence of pH and chloride. J Photochem Photobiol A Chem 2017. [DOI: 10.1016/j.jphotochem.2016.12.030] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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9
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Yan Y, Liao QN, Ji F, Wang W, Yuan S, Hu ZH. Decomposition of 3,5-dinitrobenzamide in aqueous solution during UV/H 2O 2 and UV/TiO 2 oxidation processes. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:5360-5369. [PMID: 28013465 DOI: 10.1007/s11356-016-8245-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 12/11/2016] [Indexed: 06/06/2023]
Abstract
3,5-Dinitrobenzamide has been widely used as a feed additive to control coccidiosis in poultry, and part of the added 3,5-dinitrobenzamide is excreted into wastewater and surface water. The removal of 3,5-dinitrobenzamide from wastewater and surface water has not been reported in previous studies. Highly reactive hydroxyl radicals from UV/hydrogen peroxide (H2O2) and UV/titanium dioxide (TiO2) advanced oxidation processes (AOPs) can decompose organic contaminants efficiently. In this study, the decomposition of 3,5-dinitrobenzamide in aqueous solution during UV/H2O2 and UV/TiO2 oxidation processes was investigated. The decomposition of 3,5-dinitrobenzamide fits well with a fluence-based pseudo-first-order kinetics model. The decomposition in both two oxidation processes was affected by solution pH, and was inhibited under alkaline conditions. Inorganic anions such as NO3-, Cl-, SO42-, HCO3-, and CO32- inhibited the degradation of 3,5-dinitrobenzamide during the UV/H2O2 and UV/TiO2 oxidation processes. After complete decomposition in both oxidation processes, approximately 50% of 3,5-dinitrobenzamide was decomposed into organic intermediates, and the rest was mineralized to CO2, H2O, and other inorganic anions. Ions such as NH4+, NO3-, and NO2- were released into aqueous solution during the degradation. The primary decomposition products of 3,5-dinitrobenzamide were identified using time-of-flight mass spectrometry (LCMS-IT-TOF). Based on these products and ions release, a possible decomposition pathway of 3,5-dinitrobenzamide in both UV/H2O2 and UV/TiO2 processes was proposed.
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Affiliation(s)
- Yingjie Yan
- School of Civil Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Qi-Nan Liao
- Chongqing Electric Power Design Institute, State Grid Chongqing Electric Power Company, Chongqing, 401121, China
| | - Feng Ji
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China.
| | - Wei Wang
- School of Civil Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Shoujun Yuan
- School of Civil Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Zhen-Hu Hu
- School of Civil Engineering, Hefei University of Technology, Hefei, 230009, China.
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10
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Tang LL, DeNardo MA, Gayathri C, Gil RR, Kanda R, Collins TJ. TAML/H2O2 Oxidative Degradation of Metaldehyde: Pursuing Better Water Treatment for the Most Persistent Pollutants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:5261-5268. [PMID: 27088657 DOI: 10.1021/acs.est.5b05518] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The extremely persistent molluscicide, metaldehyde, widely used on farms and gardens, is often detected in drinking water sources of various countries at concentrations of regulatory concern. Metaldehyde contamination restricts treatment options. Conventional technologies for remediating dilute organics in drinking water, activated carbon, and ozone, are insufficiently effective against metaldehyde. Some treatment plants have resorted to effective, but more costly UV/H2O2. Here we have examined if TAML/H2O2 can decompose metaldehyde under laboratory conditions to guide development of a better real world option. TAML/H2O2 slowly degrades metaldehyde to acetaldehyde and acetic acid. Nuclear magnetic resonance spectroscopy ((1)H NMR) was used to monitor the degradation-the technique requires a high metaldehyde concentration (60 ppm). Within the pH range of 6.5-9, the reaction rate is greatest at pH 7. Under optimum conditions, one aliquot of TAML 1a (400 nM) catalyzed 5% degradation over 10 h with a turnover number of 40. Five sequential TAML aliquots (2 μM overall) effected a 31% removal over 60 h. TAML/H2O2 degraded metaldehyde steadily over many hours, highlighting an important long-service property. The observation of metaldehyde decomposition under mild conditions provides a further indication that TAML catalysis holds promise for advancing water treatment. These results have turned our attention to more aggressive TAML activators in development, which we expect will advance the observed technical performance.
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Affiliation(s)
- Liang L Tang
- Department of Chemistry, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Matthew A DeNardo
- Department of Chemistry, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Chakicherla Gayathri
- Department of Chemistry, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Roberto R Gil
- Department of Chemistry, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Rakesh Kanda
- Institute for the Environment, Brunel University , Halsbury Building (130), Kingston Lane, Uxbridge, Middlesex, UB8 3PH, United Kingdom
| | - Terrence J Collins
- Department of Chemistry, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
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11
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Semitsoglou-Tsiapou S, Templeton MR, Graham NJD, Hernández Leal L, Martijn BJ, Royce A, Kruithof JC. Low pressure UV/H2O2 treatment for the degradation of the pesticides metaldehyde, clopyralid and mecoprop - Kinetics and reaction product formation. WATER RESEARCH 2016; 91:285-94. [PMID: 26803264 DOI: 10.1016/j.watres.2016.01.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 12/19/2015] [Accepted: 01/09/2016] [Indexed: 05/23/2023]
Abstract
The degradation kinetics of three pesticides - metaldehyde, clopyralid and mecoprop - by ultraviolet photolysis and hydroxyl radical oxidation by low pressure ultraviolet hydrogen peroxide (LP-UV/H2O2) advanced oxidation was determined. Mecoprop was susceptible to both LP-UV photolysis and hydroxyl radical oxidation, and exhibited the fastest degradation kinetics, achieving 99.6% (2.4-log) degradation with a UV fluence of 800 mJ/cm(2) and 5 mg/L hydrogen peroxide. Metaldehyde was poorly degraded by LP-UV photolysis while 97.7% (1.6-log) degradation was achieved with LP-UV/H2O2 treatment at the maximum tested UV fluence of 1000 mJ/cm(2) and 15 mg/L hydrogen peroxide. Clopyralid was hardly susceptible to LP-UV photolysis and exhibited the lowest degradation by LP-UV/H2O2 among the three pesticides. The second-order reaction rate constants for the reactions between the pesticides and OH-radicals were calculated applying a kinetic model for LP-UV/H2O2 treatment to be 3.6 × 10(8), 2.0 × 10(8) and 1.1 × 10(9) M(-1) s(-1) for metaldehyde, clopyralid and mecoprop, respectively. The main LP-UV photolysis reaction product from mecoprop was 2-(4-hydroxy-2-methylphenoxy) propanoic acid, while photo-oxidation by LP-UV/H2O2 treatment formed several oxidation products. The photo-oxidation of clopyralid involved either hydroxylation or dechlorination of the ring, while metaldehyde underwent hydroxylation and produced acetic acid as a major end product. Based on the findings, degradation pathways for the three pesticides by LP-UV/H2O2 treatment were proposed.
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Affiliation(s)
- Sofia Semitsoglou-Tsiapou
- Department of Civil and Environmental Engineering, Imperial College London, London, UK; Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands.
| | - Michael R Templeton
- Department of Civil and Environmental Engineering, Imperial College London, London, UK
| | - Nigel J D Graham
- Department of Civil and Environmental Engineering, Imperial College London, London, UK
| | - Lucía Hernández Leal
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands
| | | | - Alan Royce
- Trojan Technologies, London, Ontario, Canada
| | - Joop C Kruithof
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands
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12
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Song C, Wang L, Ren J, Lv B, Sun Z, Yan J, Li X, Liu J. Comparative study of diethyl phthalate degradation by UV/H2O2 and UV/TiO2: kinetics, mechanism, and effects of operational parameters. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:2640-2650. [PMID: 26432268 DOI: 10.1007/s11356-015-5481-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 09/21/2015] [Indexed: 06/05/2023]
Abstract
The photodegradation of diethyl phthalate (DEP) by UV/H2O2 and UV/TiO2 is studied. The DEP degradation kinetics and multiple crucial factors effecting the clearance of DEP are investigated, including initial DEP concentration ([DEP]0), initial pH values (pH0), UV light intensity, anions (Cl(-), NO(3-), SO4 (2-), HCO3 (-), and CO3 (2-)), cations (Mg(2+), Ca(2+), Mn(2+), and Fe(3+)), and humic acid (HA). Total organic carbon (TOC) removal is tested by two treatments. And, cytotoxicity evolution of DEP degradation intermediates is detected. The relationship between molar ratio ([H2O2]/[DEP] or [TiO2]/[DEP]) and degradation kinetic constant (K) is also studied. And, the cytotoxicity tests of DEP and its degradation intermediates in UV/H2O2 and UV/TiO2 treatments are researched. The DEP removal efficiency of UV/H2O2 treatment is higher than UV/TiO2 treatment. The DEP degradation fitted a pseudo-first-order kinetic pattern under experimental conditions. The K linearly related with molar ratio in UV/H2O2 treatment while nature exponential relationship is observed in the case of UV/TiO2. However, K fitted corresponding trends better in H2O2 treatment than in TiO2 treatment. The Cl(-) is in favor of the DEP degradation in UV/H2O2 treatment; in contrast, it is disadvantageous to the DEP degradation in UV/TiO2 treatment. Other anions are all disadvantageous to the DEP degradation in two treatments. Fe(3+) promotes the degradation rates significantly. And, all other cations in question inhibit the degradation of DEP. HA hinders DEP degradation in two treatments. The intermediates of DEP degradation in UV/TiO2 treatment are less toxic to biological cell than that in UV/H2O2 treatment.
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Affiliation(s)
- Chengjie Song
- School of Environmental and Safety Engineering, Changzhou University, Changzhou, People's Republic of China
| | - Liping Wang
- School of Environmental and Safety Engineering, Changzhou University, Changzhou, People's Republic of China.
| | - Jie Ren
- School of Pharmaceutical and Life Sciences, Changzhou University, Changzhou, People's Republic of China
| | - Bo Lv
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, People's Republic of China
| | - Zhonghao Sun
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, People's Republic of China
| | - Jing Yan
- College of Environmental Science and Engineering, Tongji University, Shanghai, People's Republic of China
| | - Xinying Li
- School of Environmental and Safety Engineering, Changzhou University, Changzhou, People's Republic of China
| | - Jingjing Liu
- School of Environmental and Safety Engineering, Changzhou University, Changzhou, People's Republic of China
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13
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Hallett KC, Atfield A, Comber S, Hutchinson TH. Developmental toxicity of metaldehyde in the embryos of Lymnaea stagnalis (Gastropoda: Pulmonata) co-exposed to the synergist piperonyl butoxide. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 543:37-43. [PMID: 26575636 DOI: 10.1016/j.scitotenv.2015.11.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Revised: 11/06/2015] [Accepted: 11/07/2015] [Indexed: 06/05/2023]
Abstract
Metaldehyde is a widely used molluscicide in countries where damage to crops from slugs and snails is a major problem associated with warm and wet winters. In the UK it is estimated that over 8% of the area covered by arable crops is treated with formulated granular bait pellets containing metaldehyde as the main active ingredient. Metaldehyde is hydrophilic (log Kow=0.12), water soluble (200 mg·L(-1) at 17 °C) and has been detected in UK surface waters in the concentration range of typically 0.2-0.6 μg·L(-1) (maximum 2.7 μg·L(-1)) during 2008-2011. In the absence of chronic data on potential hazards to non-target freshwater molluscs, a laboratory study was conducted to investigate the impact of metaldehyde on embryo development in the gastropod Lymnaea stagnalis (RENILYS strain) and using zinc as a positive control. L. stagnalis embryos were exposed to metaldehyde under semi-static conditions at 20±1 °C and hatching success and growth (measured as shell height and intraocular distance) examined after 21 d. Exposure concentrations were verified using HPLC and gave 21 d (hatching)NOEC and (hatching)LOEC mean measured values of 36 and 116 mg MET·L(-1), respectively (equal to the 21 d (shell height)NOEC and (shell height)LOEC values). For basic research purposes, a second group of L. stagnalis embryos was co-exposed to metaldehyde and the pesticide synergist piperonyl butoxide (PBO). Co-exposure to the PBO (measured concentrations between 0.47-0.56 mg·L(-1)) reduced hatching success from 100% to 47% and resulted in a 30% reduction in embryo growth (shell height) in snail embryos co-exposed to metaldehyde at 34-36 mg·L(-1) over 21 d. In conclusion, these data suggest mollusc embryos may have some metabolic detoxication capacity for metaldehyde and further work is warranted to explore this aspect in order to support the recent initiative to include molluscs in the OECD test guideline programme.
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Affiliation(s)
- Katrina C Hallett
- School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
| | - Andrew Atfield
- School of Biological Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
| | - Sean Comber
- School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
| | - Thomas H Hutchinson
- School of Biological Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK.
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14
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An Y, de Ridder DJ, Zhao C, Schoutteten K, Bussche JV, Zheng H, Chen G, Vanhaecke L. Adsorption and photocatalytic degradation of pharmaceuticals and pesticides by carbon doped-TiO2 coated on zeolites under solar light irradiation. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2016; 73:2868-2881. [PMID: 27332831 DOI: 10.2166/wst.2016.146] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
To evaluate the performance of zeolite-supported carbon-doped TiO(2) composite catalysts toward target pollutants under solar light irradiation, the adsorption and photocatalytic degradation of 18 pharmaceuticals and pesticides with distinguishing features (molecular size and volume, and photolysis) were investigated using mordenite zeolites with SiO(2)/Al(2)O(3) ratios of 18 and 240. Different quantities of carbon-doped TiO(2) were coated on the zeolites, and then the finished composite catalysts were tested in demineralized, surface, and hospital wastewater samples, respectively. The composite photocatalysts were characterized by X-ray diffraction, field emission scanning electron microscopy, and surface area and porosity analyses. Results showed that a dispersed layer of carbon-doped TiO(2) is formed on the zeolite surface; this layer blocks the micropores of zeolites and reduces their surface area. However, these reductions did not significantly affect adsorption onto the zeolites. Our results demonstrated that zeolite-supported carbon-doped TiO(2) systems can effectively degrade 18 pharmaceuticals and pesticides in demineralized water under natural and simulated solar light irradiation. In surface and hospital wastewaters, zeolite-supported carbon-doped TiO(2) systems present excellent anti-interference capability against radical scavengers and competitive organics for pollutants removal, and higher pollutants adsorption on zeolites evidently enhances the removal rate of target pollutants in surface and hospital wastewater samples with a complicated matrix.
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Affiliation(s)
- Ye An
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China E-mail: ; ; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400045, China; These authors contributed to the work equally and should be regarded as co-first authors
| | - David Johannes de Ridder
- Ghent University, Coupure Links 653, B-9000 Gent, Belgium; Delft University of Technology, PO Box 5048, 2600 GA Delft, The Netherlands; These authors contributed to the work equally and should be regarded as co-first authors
| | - Chun Zhao
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China E-mail: ; ; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400045, China
| | - Klaas Schoutteten
- Ghent University, Coupure Links 653, B-9000 Gent, Belgium; These authors also contributed equally to this work
| | - Julie Vanden Bussche
- Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium; These authors also contributed equally to this work
| | - Huaili Zheng
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China E-mail: ; ; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400045, China; These authors also contributed equally to this work
| | - Gang Chen
- Chemistry and Chemical Engineering, Chongqing University, Chongqing 400045, China; These authors also contributed equally to this work
| | - Lynn Vanhaecke
- Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium; These authors also contributed equally to this work
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15
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Adak A, Mangalgiri KP, Lee J, Blaney L. UV irradiation and UV-H₂O₂ advanced oxidation of the roxarsone and nitarsone organoarsenicals. WATER RESEARCH 2015; 70:74-85. [PMID: 25514660 DOI: 10.1016/j.watres.2014.11.025] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Revised: 11/10/2014] [Accepted: 11/15/2014] [Indexed: 06/04/2023]
Abstract
Roxarsone (ROX) and nitarsone (NIT) are used as additives in animal feeding operations and have been detected in animal manure, agricultural retention ponds, and adjacent surface waters. This work investigates treatment of organoarsenicals using UV-based treatment processes, namely UV irradiation at 253.7 nm and the UV-H2O2 advanced oxidation process. The apparent molar absorptivity was mapped for ROX and NIT across pH and wavelength. For UV irradiation at 253.7 nm, the fluence-based pseudo-first order rate constant (kp(')) and effective quantum yield (Φ) for ROX were 8.10-29.7 × 10(-5) cm(2)/mJ and 2.34-8.37 × 10(-3) mol/E, respectively; the corresponding constants were slightly lower for NIT. The observed rate constants are higher during advanced oxidation (e.g., kp,ROX(')=3.92(±0.19)-217(±48) × 10(-4) cm(2)/mJ). Second order rate constants for organoarsenical transformation by hydroxyl radicals were determined to be 3.40(±0.45) × 10(9) and 8.28(±0.49) × 10(8) M(-1)s(-1) for ROX and NIT, respectively. Solution pH and nitrate concentration did not significantly impact ROX transformation during advanced oxidation; however, bicarbonate and dissolved organic matter from chicken litter reduced ROX transformation through hydroxyl radical scavenging. Inorganic arsenic was the predominant transformation product of ROX during UV-H2O2 treatment.
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Affiliation(s)
- Asok Adak
- Department of Civil Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, West Bengal 711103, India; Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Kiranmayi P Mangalgiri
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Jessica Lee
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Lee Blaney
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
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16
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Buthiyappan A, Abdul Aziz AR, Wan Daud WMA. Degradation performance and cost implication of UV-integrated advanced oxidation processes for wastewater treatments. REV CHEM ENG 2015. [DOI: 10.1515/revce-2014-0039] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractAdvanced oxidation processes (AOPs) are commonly used for treating recalcitrant wastewater with varying degree of efficiency, depending on several operating parameters. In this review, a comparative study among selected AOPs integrated with ultraviolet (UV) (UV/Fenton, UV/H
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17
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Busquets R, Kozynchenko OP, Whitby RLD, Tennison SR, Cundy AB. Phenolic carbon tailored for the removal of polar organic contaminants from water: a solution to the metaldehyde problem? WATER RESEARCH 2014; 61:46-56. [PMID: 24880244 DOI: 10.1016/j.watres.2014.04.048] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 04/08/2014] [Accepted: 04/29/2014] [Indexed: 06/03/2023]
Abstract
Current water treatment technologies are inefficient at treating water contaminated with metaldehyde, an 8-member cyclic tetramer of acetaldehyde widely used as a molluscicide in large-scale agriculture and in gardens, and which has been frequently observed to breach European regulatory limits in the UK due to its high solubility and frequent use. Here, we examine the controls on metaldehyde adsorption onto activated phenolic carbon, namely the influence of activation degree, pore size distribution, particle size, point of zero charge and surface functionalisation, by synthesising "tailored" carbons from phenolic resin. Metaldehyde adsorption has been found to be independent of specific surface area (SBET), which is highly unusual for an adsorption process, and is favoured in carbons with (a) high microporosity with narrow pore size distribution, (b) presence of mesopores which allow efficient diffusive transport, and (c) an absence of negatively charged functional groups. The maximum adsorption capacity of the phenolic resin-derived carbons, tested at an elevated (i.e. exceeding environmental levels) water concentration of 64 mg metaldehyde/L, was 76 mg metaldehyde/g carbon compared with 13 mg metaldehyde/g carbon in industrial granular activated carbon (GAC). The phenolic resin-derived carbons and GAC showed similar adsorption kinetics with maximum metaldehyde uptake occurring within 30 min under batch adsorption conditions, although adsorption isotherms indicate much stronger adsorption of metaldehyde on the phenolic resin-derived carbons. Adsorption efficiency for metaldehyde was maintained even in the presence of high background concentrations of organic matter and inorganic salts, indicating the potential utility of these "designer" carbons in waste and/or drinking water treatment.
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Affiliation(s)
- Rosa Busquets
- School of Environment and Technology, University of Brighton, Brighton BN2 4GJ, UK; MAST Carbon International Ltd., Jays Close, Basingstoke, Hampshire RG22 4BA, UK; School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton BN2 4GJ, UK; Kingston Universty, Faculty of Science, Engineering and Computing, Kingston Upon Thames, Surrey KT1 2EE, UK.
| | | | - Raymond L D Whitby
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton BN2 4GJ, UK; Department of Chemical Engineering, Nazarbayev University, 53 Kabanbay Batyr Avenue, Astana 010000, Kazakhstan
| | - Stephen R Tennison
- MAST Carbon International Ltd., Jays Close, Basingstoke, Hampshire RG22 4BA, UK
| | - Andrew B Cundy
- School of Environment and Technology, University of Brighton, Brighton BN2 4GJ, UK.
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18
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Tan C, Gao N, Deng Y, Deng J, Zhou S, Li J, Xin X. Radical induced degradation of acetaminophen with Fe3O4 magnetic nanoparticles as heterogeneous activator of peroxymonosulfate. JOURNAL OF HAZARDOUS MATERIALS 2014; 276:452-60. [PMID: 24929305 DOI: 10.1016/j.jhazmat.2014.05.068] [Citation(s) in RCA: 250] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 05/21/2014] [Accepted: 05/22/2014] [Indexed: 05/24/2023]
Abstract
Magnetic nano-scaled particles Fe3O4 were studied for the activation of peroxymonosulfate (PMS) to generate active radicals for degradation of acetaminophen (APAP) in water. The Fe3O4 MNPs were found to effectively catalyze PMS for removal of APAP, and the reactions well followed a pseudo-first-order kinetics pattern (R(2)>0.95). Within 120min, approximately 75% of 10ppm APAP was accomplished by 0.2mM PMS in the presence of 0.8g/L Fe3O4 MNPs with little Fe(3+) leaching (<4μg/L). Higher Fe3O4 MNP dose, lower initial APAP concentration, neutral pH, and higher reaction temperature favored the APAP degradation. The production of sulfate radicals and hydroxyl radicals was validated through two ways: (1) indirectly from the scavenging tests with scavenging agents, tert-butyl alcohol (TBA) and ethanol (EtOH); (2) directly from the electron paramagnetic resonance (ESR) tests with 0.1M 5,5-dimethyl-1-pyrrolidine N-oxide (DMPO). Plausible mechanisms on the radical generation from Fe3O4 MNP activation of PMS are proposed based on the results of radical identification tests and XPS analysis. It appeared that Fe(2+)Fe(3+) on the catalyst surface was responsible for the radical generation. The results demonstrated that Fe3O4 MNPs activated PMS is a promising technology for water pollution caused by contaminants such as pharmaceuticals.
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Affiliation(s)
- Chaoqun Tan
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai City 200092, China
| | - Naiyun Gao
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai City 200092, China.
| | - Yang Deng
- Department of Earth and Environmental Studies, Montclair State University, Montclair, NJ 07043, USA
| | - Jing Deng
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai City 200092, China
| | - Shiqing Zhou
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai City 200092, China
| | - Jun Li
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai City 200092, China
| | - Xiaoyan Xin
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai City 200092, China
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19
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Keeley J, Smith AD, Judd SJ, Jarvis P. Reuse of recovered coagulants in water treatment: An investigation on the effect coagulant purity has on treatment performance. Sep Purif Technol 2014. [DOI: 10.1016/j.seppur.2014.04.033] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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20
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James CP, Germain E, Judd S. Micropollutant removal by advanced oxidation of microfiltered secondary effluent for water reuse. Sep Purif Technol 2014. [DOI: 10.1016/j.seppur.2014.02.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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21
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Tao B, Fletcher AJ. Catalytic degradation and adsorption of metaldehyde from drinking water by functionalized mesoporous silicas and ion-exchange resin. Sep Purif Technol 2014. [DOI: 10.1016/j.seppur.2014.01.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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22
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Agulló-Barceló M, Moss J, Green J, Gillespie S, Codony F, Lucena F, Nocker A. Quantification of relative proportions of intact cells in microbiological samples using the example of Cryptosporidium parvum
oocysts. Lett Appl Microbiol 2013; 58:70-8. [DOI: 10.1111/lam.12157] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 09/04/2013] [Accepted: 09/05/2013] [Indexed: 12/21/2022]
Affiliation(s)
- M. Agulló-Barceló
- Department of Microbiology; Faculty of Biology; Universitat de Barcelona; Barcelona Spain
| | - J.A. Moss
- Center for Environmental Diagnostics and Bioremediation; University of West Florida; Pensacola FL USA
| | - J. Green
- Scottish Water; Juniper House; Heriot Watt Research Park; Edinburgh UK
| | - S. Gillespie
- Scottish Water; Juniper House; Heriot Watt Research Park; Edinburgh UK
| | - F. Codony
- Laboratori de Microbiologia Sanitària i Mediambiental (MSM-Lab); Universitat Politècnica de Catalunya; Terrassa Barcelona Spain
| | - F. Lucena
- Department of Microbiology; Faculty of Biology; Universitat de Barcelona; Barcelona Spain
| | - A. Nocker
- Cranfield Water Science Institute; Cranfield University; Cranfield Bedfordshire UK
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23
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Autin O, Romelot C, Rust L, Hart J, Jarvis P, MacAdam J, Parsons SA, Jefferson B. Evaluation of a UV-light emitting diodes unit for the removal of micropollutants in water for low energy advanced oxidation processes. CHEMOSPHERE 2013; 92:745-751. [PMID: 23668964 DOI: 10.1016/j.chemosphere.2013.04.028] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 04/09/2013] [Accepted: 04/11/2013] [Indexed: 06/02/2023]
Abstract
There is growing interest in using light emitting diodes (LEDs) as alternative to traditional mercury lamps for the removal of micropollutants by advanced oxidation processes due to their low energy consumption and potential for high efficiency and long lifetime. This study investigates the penetration and coverage of the light emitted by LEDs in order to build an optimised LED collimated beam apparatus. From the experimental data, cost analysis was conducted in order to identify when LEDs will become economically viable. It was observed that if their development follows the predictions, LEDs should be a viable alternative to traditional lamps within 7yr for both UV/H2O2 and UV/TiO2 processes. However, parameters such as wall plug efficiency and input power need to improve for LEDs to become competitive.
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Affiliation(s)
- Olivier Autin
- Cranfield Water Science Institute, Department of Environmental Science and Technology, Cranfield University, Bedfordshire MK43 0AL, UK
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24
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Autin O, Hart J, Jarvis P, MacAdam J, Parsons SA, Jefferson B. The impact of background organic matter and alkalinity on the degradation of the pesticide metaldehyde by two advanced oxidation processes: UV/H₂O₂ and UV/TiO₂. WATER RESEARCH 2013; 47:2041-2049. [PMID: 23402886 DOI: 10.1016/j.watres.2013.01.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 01/09/2013] [Accepted: 01/10/2013] [Indexed: 06/01/2023]
Abstract
The impact of background constituents on the degradation of trace levels of micropollutants by two advanced oxidation processes: UV/H₂O₂ and UV/TiO₂ was studied. Experimental results demonstrated that the background scavenging rate rather than the concentration of micropollutant controls the required UV irradiation dose. The character of the natural organic matter had a limited impact on scavenging when the water source remains unchanged, however, a periodic bleed of hydrophobic material may substantially increase the minimum UV dose required to reach the desired micropollutant concentration. Moreover, in the case of UV/TiO₂, high concentrations of background organic matter do not only act as scavengers but also saturate the TiO₂ surface. Alkalinity inhibits the efficacy of UV/TiO₂ photocatalysis due to the formation of large TiO₂ aggregates. The study also demonstrated that the use of synthetic waters for treatability test purposes was an acceptable approach as long as both the background organic matter and the alkalinity were matched to that of the projected application. Finally spiking micropollutants at higher concentrations does not alter the significance of the findings as long as the background constituents represent more than 85% of the total scavenging rate.
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