title: Oxidative degradation of different chlorinated phenoxyalkanoic acid herbicides by a hybrid ZrO2 gel-derived catalyst without light irradiation.
abstract: The oxidative degradation of 2-methyl-4-chlorophenoxyacetic acid (MCPA), 4-(4-chloro-2-methylphenoxy)butanoic acid (MCPB), 4-chlorophenoxyacetic acid (4-CPA) and 2,4-dichlorophenoxyacetic acid (2,4 D) by ZrO2-acetylacetonate hybrid catalyst (HSGZ) without light irradiation was assessed. The thermal stability of the catalyst was investigated by thermogravimetry, differential thermal analysis, and Fourier transform infrared spectroscopy. For each herbicide, a virtually complete removal in about 3 days without light irradiation at room temperature was achieved. The removal kinetics of the herbicides has been satisfactorily characterized by a double-stage physico-mathematical model, in the hypothesis that a first-order adsorption on HSGZ surface is followed by the herbicide degradation, catalytically driven by HSGZ surface groups. The long-term use of the HSGZ catalyst was assessed by repeated-batch tests. The specific cost for unit-volume removal of herbicide was evaluated by a detailed cost analysis showing that it is comparable with those pertaining to alternative methods.
authors.affiliation: Dipartimento di Agraria and §Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l'Ambiente, l'Agro-Alimentare ed i Nuovi Materiali (CERMANU) Università di Napoli Federico II , Via Università 100, 80055 Portici (Napoli), Italy.
authors.forename: Filomena
authors.initials: F
authors.lastname: Sannino
authors.forename: Pasquale
authors.initials: P
authors.lastname: Pernice
authors.forename: Luciana
authors.initials: L
authors.lastname: Minieri
authors.forename: Gaia Aurora
authors.initials: GA
authors.lastname: Camandona
authors.forename: Antonio
authors.initials: A
authors.lastname: Aronne
authors.forename: Domenico
authors.initials: D
authors.lastname: Pirozzi
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000031:analogs & derivatives* / Q000737:chemistry*; D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000737:chemistry*; D000327:Adsorption; D001673:Biodegradation, Environmental; D002384:Catalysis; D006540:Herbicides / Q000737:chemistry*; D007700:Kinetics; D008027:Light; D010084:Oxidation-Reduction; D013818:Thermogravimetry; D015040:Zirconium / Q000737:chemistry*
chemical_list: D006540:Herbicides; D015084:2,4-Dichlorophenoxyacetic Acid; C007017:4-chlorophenoxyacetic acid; D015040:Zirconium; D008456:2-Methyl-4-chlorophenoxyacetic Acid; C028541:zirconium oxide
keywords: chlorinated phenoxyalkanoic acid herbicides; hybrid catalyst; oxidative degradation; sol−gel; zirconium oxide