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Master's Dissertation
DOI
10.11606/D.75.2018.tde-22052018-095014
Document
Author
Full name
Rodrigo Rossi de Araujo
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2018
Supervisor
Committee
Azevedo, Eduardo Bessa (President)
Daniel, Luiz Antonio
Machado, Sergio Antonio Spinola
Pointer-Malpass, Geoffroy Roger
Title in Portuguese
Degradação de metilparabeno e propilparabeno pelo processo foto-Fenton solar
Keywords in Portuguese
degradação
foto-Fenton
metilparabeno
propilparabeno
reator CPC
Abstract in Portuguese
Neste trabalho, utilizou-se um Processo Oxidativo Avançado (POA) para a degradação de uma solução aquosa contendo uma mistura de metilparabeno e propilparabeno (50 μg L-1 cada). O processo estudado foi o foto-Fenton solar, em um reator do tipo CPC operado no modo batelada com reciclo total. As condições operacionais foram otimizadas por meio da Metodologia de Superfície de Resposta (MSR), sendo elas: 771,6 μg H2O2 L-1, 65,3 μg Fe3+ L-1 e vazão 0,9 L min-1. O pH foi fixado em 2,5. A determinação das concentrações dos analitos foi realizada por Cromatografia Líquida de Alta Eficiência acoplada a um Detector de Arranjo de Diodos (CLAE-DAD), tendo sido monitorado o comprimento de onda 258 nm. Utilizou-se como técnica extratora e de pré-concentração a Microextração Líquido-Líquido Dispersiva (MELLD), sendo o n-octanol o solvente extrator e a acetona o solvente dispersivo. Avaliou-se a cinética de degradação do processo otimizado (em triplicata), obtendo-se uma degradação > 99% em 50 min. As constantes de taxa (em função da dose de energia, unidades m² kW-1) foram 1,2 ± 0,034 (R² = 0,987) e 1,1 ± 0,042 (R² = 0,979) para o metilparabeno e o propilparabeno, respectivamente. O efluente do reator mostrou-se biologicamente inativo, tendo sido testadas sua ecotoxicidade (Lactuca sativa) e sua atividade antimicrobiana (Escherichia coli).
Title in English
Methylparaben and propylparaben degradation by solar photo-Fenton process
Keywords in English
CPC reactor
degradation
methylparaben
photo-Fenton
propylparaben
Abstract in English
In this work, an Advanced Oxidation Process (AOP) was used for the degradation of aqueous methylparaben and propylparaben (50 μg L-1 each). The studied process was the solar photo-Fenton reaction, using a CPC-type reactor, which was operated in batch mode with total recycle. The experimental conditions were optimized using the Response Surface Methodology (RSM) and the obtained results were: 771.6 μg H2O2 L-1, 65.3 μg Fe3+ L-1, and flow rate 0,9 L min-1. The solution pH was set at 2.5. The analytes concentration were determined by High Efficiency Liquid Chromatography coupled to a Diode-Array Detector (HPLC-DAD), monitoring the 258 nm wavelength. The Dispersive Liquid-Liquid Extraction was used as a pre-concentration and extraction technique before injection, whereas n-octanol was the extraction solvent and acetone was the dispersive one. The optimized degradation process kinetics was assessed (triplicate) and more than 99% degradation was obtained after 50 min. The rate constants (normalized by the energy dose, m2 kW-1 units) were 1.2 ± 0.034 (Rsup>2 = 0.987) and 1.1 ± 0.042 (R2 = 0.979) for methylparaben and propylparaben, respectively. The reactor effluent was biologically inactive, regarding its ecotoxicity (Lactuca sativa) and antimicrobial activity (Escherichia coli).
 
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Publishing Date
2018-05-28
 
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