Influence of chelation on the Fenton-based electrochemical degradation of herbicide tebuthiuron

Autor: Fábio Gozzi, Sílvio C. de Oliveira, Ignasi Sirés, Enric Brillas, Amilcar Machulek
Rok vydání: 2018
Předmět:
Environmental Engineering
Health
Toxicology and Mutagenesis
Radical
Kinetics
Acer
02 engineering and technology
010501 environmental sciences
Ferric Compounds
01 natural sciences
Gas Chromatography-Mass Spectrometry
chemistry.chemical_compound
Tebuthiuron
Metal complexes
Environmental Chemistry
Chelation
Sulfate
Electrodes
Boron
0105 earth and related environmental sciences
Methylurea Compounds
Photolysis
Herbicides
Hydroxyl Radical
Sulfates
Chemistry
Public Health
Environmental and Occupational Health
Oxidació electroquímica
Electrochemical Techniques
Hydrogen Peroxide
General Medicine
General Chemistry
Mineralization (soil science)
021001 nanoscience & nanotechnology
Complexos metàl·lics
Pollution
Anode
Electrolytic oxidation
Steel
Degradation (geology)
0210 nano-technology
Oxidation-Reduction
Water Pollutants
Chemical
Nuclear chemistry
Zdroj: Dipòsit Digital de la UB
Universidad de Barcelona
ISSN: 0045-6535
DOI: 10.1016/j.chemosphere.2018.02.060
Popis: This study describes the performance of electro-Fenton (EF) and photoelectro-Fenton (PEF) processes to degrade the herbicide tebuthiuron (TBH) in 0.050 M Na2SO4 at pH = 3.0. Experiments were performed in an undivided cell equipped with a boron-doped diamond (BDD) or Pt anode and an air-diffusion cathode that produces H2O2. Physisorbed hydroxyl radicals (M( OH)) generated from water oxidation at the anode and/or free OH formed from Fenton’s reaction acted as main oxidants. All processes became much more effective using a BDD anode because of the higher oxidation power of BDD( OH). Sulfate and nitrate were the predominant ions released during TBH destruction. In both, EF and PEF treatments, two distinct kinetic regimes were observed, the first one corresponding to the oxidation of free TBH by OH and the second one to that of the Fe(III)-TBH complex by M( OH). The effect of Fe2+ and TBH concentrations on the kinetics of both regions has been examined. Moreover, a poor mineralization was reached with Pt anode, whereas almost total mineralization was attained by EF and PEF with BDD. Both processes showed analogous mineralization rates because the intermediates produced could not be photodegraded by UVA light. Gas chromatography-mass spectrometry analysis of electrolyzed solutions revealed the generation of eight heteroaromatics along with 1,3-dimethylurea, which have been included in a reaction pathway proposed for the initial degradation of TBH.
Databáze: OpenAIRE
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