title: Novel imazethapyr detoxification applying advanced oxidation processes.
abstract: Different degradation methods have been applied to assess the suitability of advanced oxidation process (AOPs) to promote mineralization of imazethapyr [(RS)-5-ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid], a widely used imidazolinone class herbicide, the persistence of which has been demonstrated in surface and ground waters destined to human uses. Independent of the oxidation process assessed, the decomposition of imazethapyr always followed a pseudo-first order kinetic. The direct UV-irradiation (UV) of the herbicide as well as its oxidation with ozone (O₃), and hydrogen peroxide tied to UV-irradiation (H₂O₂/UV) were sufficiently slow to permit the identification of intermediate products, the formation pathway of which has been proposed. Ozonation joined to UV-irradiation (O₃/UV), ozonation joined to titanium dioxide photo-catalysis (TiO₂/UV+O₃), sole photo-catalysis (TiO₂/UV), and photo-catalysis reinforced with hydrogen peroxide-oxidation (TiO₂/UV+H₂O₂) were characterized by a faster degradation and rapid formation of a lot of small molecules, which were quickly degraded to complete mineralization. The most effective oxidation methods were those using titanium dioxide photo-catalysis enhanced either by ozonation or hydrogen peroxide. Most of all, these last processes were useful to avoid the development of dangerous by-products.
authors: Department of Farm Organization & Management, University of Ioannina, Agrinio, Greece.
authors: Ioannis
authors: I
authors: Stathis
authors: Dimitra G
authors: DG
authors: Hela
authors: Laura
authors: L
authors: Scrano
authors: Filomena
authors: F
authors: Lelario
authors: Lucia
authors: L
authors: Emanuele
authors: Sabino A
authors: SA
authors: Bufo
mesh_terms: D002384:Catalysis; D006540:Herbicides / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D009539:Nicotinic Acids / Q000737:chemistry*; D010083:Oxidants, Photochemical / Q000737:chemistry / Q000528:radiation effects; D010084:Oxidation-Reduction / Q000187:drug effects / Q000528:radiation effects; D010126:Ozone / Q000737:chemistry; D014025:Titanium / Q000737:chemistry; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D006540:Herbicides; D007220:Industrial Waste; D009539:Nicotinic Acids; D010083:Oxidants, Photochemical; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D010126:Ozone; C093630:imazethapyr; D006861:Hydrogen Peroxide; D014025:Titanium