Photocatalytic degradation of diuron: experimental analyses and simulation of HO degrees radical attacks by density functional theory calculations.
The photocatalytic oxidation of diuron has been performed in presence of TiO(2) suspensions. To better understand the mechanistic details of the hydroxyl radical attack on diuron, computational methods were carried out. The combination of experimental and computational methods has been employed to establish the main degradation pathways of diuron. After identification of the majority of first byproduct, the experimental study underlined that substitution of chlorines and hydroxylation by hydroxyl radicals are the main diuron degradation pathways, in agreement with MOPAC and DFT simulations carried out in the gas phase. In addition, these calculations revealed that the aromatic ring attack is led by a HO degrees addition and not a hydrogen abstraction and the main first byproduct, monochlorohydroxylated compounds, are obtained by concerted reactions.
Université de Lyon, Université Lyon 1, CNRS-UMR 5256, IRCELYON, Institut de recherches sur la catalyse et l'environnement de Lyon, 2 avenue Albert Einstein, F-69626 Villeurbanne Cedex, France. carrier@sun.ac.za
Marion
M
Carrier
Chantal
C
Guillard
Michèle
M
Besson
Claire
C
Bordes
Henry
H
Chermette
D002244:Carbon / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry; D002384:Catalysis; D002853:Chromatography, Liquid; D004237:Diuron / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D013058:Mass Spectrometry; D008903:Minerals / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D055668:Photochemical Processes; D011789:Quantum Theory; D013481:Superoxides / Q000737:chemistry; D013816:Thermodynamics
D002264:Carboxylic Acids; D008903:Minerals; D013481:Superoxides; D017665:Hydroxyl Radical; D002244:Carbon; D004237:Diuron