Hydroxyl radical-induced degradation of fenuron in pulse and gamma radiolysis: kinetics and product analysis

Krisztina Kovács, Viktoria Mile, Tamás Csay, E. Takács, L. Wojnárovits

Research output: Article

11 Citations (Scopus)

Abstract

Radiolytic reactions of phenylureas were studied in detail with fenuron model compound in dilute aqueous solutions using pulse radiolysis for detection of the intermediates, gamma radiolysis with UV–Vis and HPLC-MS techniques for analysis of the final products. The kinetics of oxidation was followed by COD, TOC and toxicity measurements. During radiolysis of aerated solutions hydroxyl radical (OH), eaq , Hand O2 •−/HO2 reactive intermediates are produced, the degradation of solute takes place practically entirely through OH reactions. Therefore, the product distribution is similar to the distributions reported in other advanced oxidation processes with OH as main reactant. OH mainly reacts with the aromatic ring, forming cyclohexadienyl radical as an intermediate. This radical in pulse radiolysis has a wide absorption band in the 310–390 nm wavelength range with a maximum at 350 nm. Cyclohexadienyl radical reacts with dissolved O2with a rate coefficient of ∼4 × 108 mol−1 dm3s−1forming peroxy radical. The latter may eliminate HO2 giving phenols or undergoes fragmentation. The one-electron oxidant OH on average induces more than two-electron oxidations. The toxicity first increases with absorbed dose, then decreases. This increase is partly due to phenols formed during the first degradation period.

Original languageEnglish
Pages (from-to)12693-12700
Number of pages8
JournalEnvironmental Science and Pollution Research
Volume21
Issue number22
DOIs
Publication statusPublished - 2014

Fingerprint

Pulse Radiolysis
Radiolysis
Phenols
hydroxyl radical
Hydroxyl Radical
Electrons
oxidation
Degradation
kinetics
degradation
Kinetics
phenol
Oxidants
Oxidation
peroxy radical
toxicity
Toxicity
electron
Hand
High Pressure Liquid Chromatography

ASJC Scopus subject areas

  • Environmental Chemistry
  • Health, Toxicology and Mutagenesis
  • Pollution
  • Medicine(all)

Cite this

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title = "Hydroxyl radical-induced degradation of fenuron in pulse and gamma radiolysis: kinetics and product analysis",
abstract = "Radiolytic reactions of phenylureas were studied in detail with fenuron model compound in dilute aqueous solutions using pulse radiolysis for detection of the intermediates, gamma radiolysis with UV–Vis and HPLC-MS techniques for analysis of the final products. The kinetics of oxidation was followed by COD, TOC and toxicity measurements. During radiolysis of aerated solutions hydroxyl radical (•OH), eaq −, H•and O2 •−/HO2 •reactive intermediates are produced, the degradation of solute takes place practically entirely through •OH reactions. Therefore, the product distribution is similar to the distributions reported in other advanced oxidation processes with •OH as main reactant. •OH mainly reacts with the aromatic ring, forming cyclohexadienyl radical as an intermediate. This radical in pulse radiolysis has a wide absorption band in the 310–390 nm wavelength range with a maximum at 350 nm. Cyclohexadienyl radical reacts with dissolved O2with a rate coefficient of ∼4 × 108 mol−1 dm3s−1forming peroxy radical. The latter may eliminate HO2 •giving phenols or undergoes fragmentation. The one-electron oxidant •OH on average induces more than two-electron oxidations. The toxicity first increases with absorbed dose, then decreases. This increase is partly due to phenols formed during the first degradation period.",
keywords = "Advanced oxidation processes, Degradation, Fenuron, Hydrated electron, Hydroxyl radical, Radiation technology",
author = "Krisztina Kov{\'a}cs and Viktoria Mile and Tam{\'a}s Csay and E. Tak{\'a}cs and L. Wojn{\'a}rovits",
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TY - JOUR

T1 - Hydroxyl radical-induced degradation of fenuron in pulse and gamma radiolysis

T2 - kinetics and product analysis

AU - Kovács, Krisztina

AU - Mile, Viktoria

AU - Csay, Tamás

AU - Takács, E.

AU - Wojnárovits, L.

PY - 2014

Y1 - 2014

N2 - Radiolytic reactions of phenylureas were studied in detail with fenuron model compound in dilute aqueous solutions using pulse radiolysis for detection of the intermediates, gamma radiolysis with UV–Vis and HPLC-MS techniques for analysis of the final products. The kinetics of oxidation was followed by COD, TOC and toxicity measurements. During radiolysis of aerated solutions hydroxyl radical (•OH), eaq −, H•and O2 •−/HO2 •reactive intermediates are produced, the degradation of solute takes place practically entirely through •OH reactions. Therefore, the product distribution is similar to the distributions reported in other advanced oxidation processes with •OH as main reactant. •OH mainly reacts with the aromatic ring, forming cyclohexadienyl radical as an intermediate. This radical in pulse radiolysis has a wide absorption band in the 310–390 nm wavelength range with a maximum at 350 nm. Cyclohexadienyl radical reacts with dissolved O2with a rate coefficient of ∼4 × 108 mol−1 dm3s−1forming peroxy radical. The latter may eliminate HO2 •giving phenols or undergoes fragmentation. The one-electron oxidant •OH on average induces more than two-electron oxidations. The toxicity first increases with absorbed dose, then decreases. This increase is partly due to phenols formed during the first degradation period.

AB - Radiolytic reactions of phenylureas were studied in detail with fenuron model compound in dilute aqueous solutions using pulse radiolysis for detection of the intermediates, gamma radiolysis with UV–Vis and HPLC-MS techniques for analysis of the final products. The kinetics of oxidation was followed by COD, TOC and toxicity measurements. During radiolysis of aerated solutions hydroxyl radical (•OH), eaq −, H•and O2 •−/HO2 •reactive intermediates are produced, the degradation of solute takes place practically entirely through •OH reactions. Therefore, the product distribution is similar to the distributions reported in other advanced oxidation processes with •OH as main reactant. •OH mainly reacts with the aromatic ring, forming cyclohexadienyl radical as an intermediate. This radical in pulse radiolysis has a wide absorption band in the 310–390 nm wavelength range with a maximum at 350 nm. Cyclohexadienyl radical reacts with dissolved O2with a rate coefficient of ∼4 × 108 mol−1 dm3s−1forming peroxy radical. The latter may eliminate HO2 •giving phenols or undergoes fragmentation. The one-electron oxidant •OH on average induces more than two-electron oxidations. The toxicity first increases with absorbed dose, then decreases. This increase is partly due to phenols formed during the first degradation period.

KW - Advanced oxidation processes

KW - Degradation

KW - Fenuron

KW - Hydrated electron

KW - Hydroxyl radical

KW - Radiation technology

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