Reaction Kinetic Model for 2,4-Dichlorophenoxyacetic Acid Decomposition in Aqueous Media Including Direct Photolysis, Direct Ozonation, Ultraviolet C, and pH Enhancement

This report presents a comprehensive study of the degradation kinetics of herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) using ozone with and without intensification with ultraviolet C (UVC) radiation. The byproducts cause several series-parallel reactions that compete with the process of photon a...

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Detalles Bibliográficos
Autores: Gilliard, María Belén, Martin, Carlos Alberto, Cassano, Alberto Enrique, Lovato, Maria Eugenia
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2013
País:Argentina
Institución:Consejo Nacional de Investigaciones Científicas y Técnicas
Repositorio:CONICET Digital (CONICET)
Idioma:inglés
OAI Identifier:oai:ri.conicet.gov.ar:11336/8755
Acceso en línea:http://hdl.handle.net/11336/8755
Access Level:acceso abierto
Palabra clave:Ozone
2,4-Dichlorophenoxyacetic acid
UVC radiation
Reactor-reaction modeling
https://purl.org/becyt/ford/2.4
https://purl.org/becyt/ford/2
Descripción
Sumario:This report presents a comprehensive study of the degradation kinetics of herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) using ozone with and without intensification with ultraviolet C (UVC) radiation. The byproducts cause several series-parallel reactions that compete with the process of photon absorption when radiation is applied. Five processes were analyzed separately: (i) the direct photolysis of 2,4-D and its main byproducts, (ii) direct ozonation in the absence of hydroxyl radicals using tert-butyl alcohol as radical scavenger, (iii) the oxidation when ozone reacts in parallel with hydroxyl radicals, (iv) the reaction enhanced with UVC radiation, and (v) the oxidation improved by pH modifications. A kinetic model was developed on the basis of the main reaction byproducts. The corresponding parameters of the reacting system were determined (nine of its 29 kinetic constants were previously unknown). Simulation results, including a rigorous description of the reacting system and the radiation field (having dark and illuminated volumes), agree very well with the experimental data.