Avaliação da remoção da Etilenotiouréia (ETU) e 1,2,4-Triazol através de processos oxidativos avançados e adsorção

• Ano de defesa: 2012
• Autor(a) principal: Sue Ellen Costa Bottrel
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Etilenotiuréia; 1; 2; Processos oxidativos avançados; Fenton; 4-Triazol; Adsorção; Meio ambiente; Engenharia sanitária
• Link de acesso: http://hdl.handle.net/1843/ENGD-92JPDP

This study assessed the removal of the pollutants ethylenethioureia (ETU) and 1,2,3-triazole in water by Advanced Oxidation Processes (AOPs) and adsorption in activated carbon. These compounds are the main metabolites of two herbicides widely used on coffee crops (mancozeb and epoxiconazole) and, in addition to being classified as persistent, they have high solubility in water (20° C) which means that they are easily spread in the environment and can lead to the contamination of water bodies. Studies have shown that the conventional water treatment methods often are not effective in the removal of persistent organic compounds (eg. pesticides, alkanes, surfactants, among other). It is known that the adsorption on activated carbon has been used in some Water Treatment Plants (WTPs). Nevertheless, its use is not always preceded by studies to ensure its efficiency. In order to demonstrate the importance of choosing the appropriate materials, in addition to understanding the adsorption process of each pollutant, this study established a comparison between two commercial activated carbons used in WTPs. One activated carbon was prepared from vegetal source and the other from animal bones from slaughterhouse. Besides characterization of the material, studies of adsorption processes of ETU and 1,2,4-triazole were performed with both materials. The activated carbon from animal bones proved to be inefficient in the removal of two compounds, unlike the vegetal source activated carbon, which showed efficiency of 50%and 80% in removal of the ETU and 1,2,4-triazol, respectively. In the second stage of this work Fenton and photo Fenton tests (AOP) were performed in aqueous solutions of the two pollutants. Fenton tests were conducted according to the factorial design to investigate the best process configuration in terms of concentrations of reagents (Fe2+ and H2O2) and pollutants in a reaction time of 60 min. The photo Fenton tests were planned according to the results and conclusions obtained in the Fenton process. In experiments with ETU up to 29% mineralization was obtained in the Fenton test and 100 in the photo Fenton and peroxidation/UV process. The 1,2,4-triazole showed better removal results in the experiments, with a Fenton maximum mineralization efficiency of 59% and in the presence of UV light it was possible to achieve 100% removal.