title: Photodegradation of neonicotinoid insecticides in water by semiconductor oxides.
abstract: The photocatalytic degradation of three neonicotinoid insecticides (NIs), thiamethoxam (TH), imidacloprid (IM) and acetamiprid (AC), in pure water has been studied using zinc oxide (ZnO) and titanium dioxide (TiO2) as photocatalysts under natural sunlight and artificial light irradiation. Photocatalytic experiments showed that the addition of these chalcogenide oxides in tandem with the electron acceptor (Na2S2O8) strongly enhances the degradation rate of these compounds in comparison with those carried out with ZnO and TiO2 alone and photolytic tests. Comparison of catalysts showed that ZnO is the most efficient for the removal of such insecticides in optimal conditions and at constant volumetric rate of photon absorption. Thus, the complete disappearance of all the studied compounds was achieved after 10 and 30 min of artificial light irradiation, in the ZnO/Na2S2O8 and TiO2/Na2S2O8 systems, respectively. The highest degradation rate was noticed for IM, while the lowest rate constant was obtained for AC under artificial light irradiation. In addition, solar irradiation was more efficient compared to artificial light for the removal of these insecticides from water. The main photocatalytic intermediates detected during the degradation of NIs were identified.
authors.affiliation: Departamento de Calidad y Garantía Alimentaria, Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA), C/ Mayor s/n. La Alberca, 30150, Murcia, Spain. jose.fenoll@carm.es.
authors.forename: José
authors.initials: J
authors.lastname: Fenoll
authors.affiliation: Departamento de Calidad y Garantía Alimentaria, Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA), C/ Mayor s/n. La Alberca, 30150, Murcia, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Garrido
authors.affiliation: Departamento de Calidad y Garantía Alimentaria, Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA), C/ Mayor s/n. La Alberca, 30150, Murcia, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Hellín
authors.affiliation: Departamento de Calidad y Garantía Alimentaria, Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA), C/ Mayor s/n. La Alberca, 30150, Murcia, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Flores
authors.affiliation: Departamento de Química Agrícola, Geología y Edafología, Facultad de Química, Universidad de Murcia, Campus Universitario de Espinardo, 30100, Murcia, Spain.
authors.forename: Simón
authors.initials: S
authors.lastname: Navarro
mesh_terms: D000691:Anabasine / Q000032:analysis* / Q000528:radiation effects; D002384:Catalysis; D004867:Equipment Design; D007306:Insecticides / Q000032:analysis* / Q000528:radiation effects; D008027:Light; D010782:Photolysis; D012666:Semiconductors; D013472:Sunlight; D014025:Titanium / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000528:radiation effects; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D007306:Insecticides; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D014025:Titanium; D000691:Anabasine; D015034:Zinc Oxide
keywords: Acetamiprid; Imidacloprid; Photocatalytic oxidation; Thiamethoxam; TiO2; Water detoxification; ZnO