Degradação do Ácido Diclorofenoxiacético (2,4-D) com ozônio eletrogerado

• Ano de defesa: 2010
• Autor(a) principal: Castro, Fernando Delalibera de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Uberlândia; BR; Programa de Pós-graduação em Química; Ciências Exatas e da Terra; UFU
• Palavras-chave em Português: Ozônio; 2,4-D; Eletrogerado; Degradação; Mineralização; Ozonização; Ozone; Electrogered; Degradation; Mineralization; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA
• Link de acesso: https://repositorio.ufu.br/handle/123456789/17324

Electrochemically generated ozone was applied on degradation of the herbicide 2,4- dichlorophenoxyacetic acid (2,4-D), in acid and alkaline solutions, under semi-batch condition using a column bubble reactor. Oxidation of 2,4-D was studied using different experimental approaches in order to assess the oxidative process (degradation and partial mineralization) from different points of view. Structural changes of 2,4-D during ozonation were quantified monitoring the decrease of the integrated absorbance (190-310 nm) while its conversion in ozonation by-products and/or mineral substances was quantified using the Gas Chromatography (GC) and Total Organic Carbon (TOC) techniques. Measurements of TOC and Chemical Oxygen Demand (COD) revealed that only a small amount of 2,4-D was mineralized during ozonation. Also verified is that alkaline conditions resulted in a more rapid removal and/or degradation of 2,4-D. Pseudo-first order kinetics was used in order to determine the different rate constants obtained for degradation of 2,4-D. Oxidation susceptibility of the organic matter measured through the COD/TOC ratio revealed that ozonation (acid and alkaline conditions) can lead to a reduction in the recalcitrance nature of the degraded organic matter in comparison with the parental compound (2,4-D).