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Low pressure UV/H2O2 treatment for the degradation of the pesticides metaldehyde, clopyralid and mecoprop - Kinetics and reaction product formation.
Water Res. 2016 Mar 15; 91:285-94.WR

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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Authors+Show Affiliations

Semitsoglou-Tsiapou S
Department of Civil and Environmental Engineering, Imperial College London, London, UK; Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands. Electronic address: s.semitsoglou-tsiapou12@imperial.ac.uk.
Templeton MR
Department of Civil and Environmental Engineering, Imperial College London, London, UK.
Graham NJ
Department of Civil and Environmental Engineering, Imperial College London, London, UK.
Hernández Leal L
Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands.
Martijn BJ
PWN Technologies, Velserbroek, The Netherlands.
Royce A
Trojan Technologies, London, Ontario, Canada.
Kruithof JC
Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands.

MeSH

2-Methyl-4-chlorophenoxyacetic AcidAcetaldehydeHerbicidesHydrogen PeroxideHydroxyl RadicalKineticsMolluscacidesOxidation-ReductionPhotolysisPicolinic AcidsPressureUltraviolet RaysWater Pollutants, ChemicalWater Purification

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

26803264

Citation

Semitsoglou-Tsiapou, Sofia, et al. "Low Pressure UV/H2O2 Treatment for the Degradation of the Pesticides Metaldehyde, Clopyralid and Mecoprop - Kinetics and Reaction Product Formation." Water Research, vol. 91, 2016, pp. 285-94.
Semitsoglou-Tsiapou S, Templeton MR, Graham NJ, et al. Low pressure UV/H2O2 treatment for the degradation of the pesticides metaldehyde, clopyralid and mecoprop - Kinetics and reaction product formation. Water Res. 2016;91:285-94.
Semitsoglou-Tsiapou, S., Templeton, M. R., Graham, N. J., Hernández Leal, L., Martijn, B. J., Royce, A., & Kruithof, J. C. (2016). Low pressure UV/H2O2 treatment for the degradation of the pesticides metaldehyde, clopyralid and mecoprop - Kinetics and reaction product formation. Water Research, 91, 285-94. https://doi.org/10.1016/j.watres.2016.01.017
Semitsoglou-Tsiapou S, et al. Low Pressure UV/H2O2 Treatment for the Degradation of the Pesticides Metaldehyde, Clopyralid and Mecoprop - Kinetics and Reaction Product Formation. Water Res. 2016 Mar 15;91:285-94. PubMed PMID: 26803264.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Low pressure UV/H2O2 treatment for the degradation of the pesticides metaldehyde, clopyralid and mecoprop - Kinetics and reaction product formation. AU - Semitsoglou-Tsiapou,Sofia, AU - Templeton,Michael R, AU - Graham,Nigel J D, AU - Hernández Leal,Lucía, AU - Martijn,Bram J, AU - Royce,Alan, AU - Kruithof,Joop C, Y1 - 2016/01/12/ PY - 2015/09/19/received PY - 2015/12/19/revised PY - 2016/01/09/accepted PY - 2016/1/25/entrez PY - 2016/1/25/pubmed PY - 2016/11/3/medline KW - Clopyralid KW - Kinetics KW - LP-UV/H(2)O(2) KW - Mecoprop KW - Metaldehyde KW - Reaction products SP - 285 EP - 94 JF - Water research JO - Water Res VL - 91 N2 - 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. SN - 1879-2448 UR - https://www.unboundmedicine.com/medline/citation/26803264/Low_pressure_UV/H2O2_treatment_for_the_degradation_of_the_pesticides_metaldehyde_clopyralid_and_mecoprop___Kinetics_and_reaction_product_formation_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0043-1354(16)30017-3 DB - PRIME DP - Unbound Medicine ER -