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 UVirradiation (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 photocatalysis (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 smallmolecules, 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. © Taylor & Francis Group, LLC.

Novel imazethapyr detoxification applying advanced oxidation processes

SCRANO, Laura
Writing – Original Draft Preparation
;
LELARIO, FILOMENA
Investigation
;
BUFO, Sabino Aurelio
2011

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 UVirradiation (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 photocatalysis (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 smallmolecules, 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. © Taylor & Francis Group, LLC.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11563/5121
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