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Previous issue date: 2017-04-27 / A progressiva demanda por ?gua tem feito do tratamento e reutiliza??o de efluentes um tema de relev?ncia mundial. Considerando tal situa??o, v?m sendo realizadas investiga??es acerca do uso de materiais nanom?tricos para obten??o de nanocompostos com propriedades antibacterianas. No sentido de aperfei?oar a obten??o de novos materiais, v?rias metodologias e t?cnicas de prepara??o t?m sido desenvolvidas com o objetivo de controlar a forma e tamanho de part?culas, o que, consequentemente, ir? melhorar e otimizar suas propriedades. Este trabalho consiste na obten??o, caracteriza??o e avalia??o antibacteriol?gica de nanocompostos obtidos pela impregna??o da prata (Ag) na alumina comercial (Y-Al2O3) e no ?xido de zinco (ZnO) a partir de diferentes rotas de s?nteses: m?todo hidrotermal assistido por micro-ondas, sonoqu?mico e associa??o do sonoqu?mico e hidrotermal, destinados a desinfec??o de ?guas residu?rias. Realizou-se um estudo comparativo entre as nanopart?culas Y-Al2O3 e ZnO sintetizada via m?todos sonoqu?mico e hidrotermal por micro-ondas, averiguando a influ?ncia da composi??o e distribui??o do tamanho de part?culas nas propriedades destas. Foram testadas impregna??es de 4%, 8%, 12% e 16% de Ag na Y-Al2O3 e no ZnO. Aplicou-se os nanop?s em efluente proveniente de ETE compacta (Esta??o de tratamento de esgoto), ap?s a etapa do tratamento secund?rio, e em seguida, avaliou-se atrav?s de an?lises bacteriol?gicas, a efici?ncia na remo??o dos indicadores patog?nicos de contamina??o. Os resultados referentes ao emprego do nanocomp?sito ZnO impregnado com 8% de Ag, na propor??o de 0,3g/300mL, por um tempo de contato de 30 minutos, apontaram uma efici?ncia de 99,99% na remo??o de coliformes totais, coliformes termotolerantes e Escherichia coli, alcan?ando padr?es iguais ou superiores ?s t?cnicas j? consagradas de desinfec??o. Os par?metros de rede dos nanocompostos obtidos atrav?s de DRX, juntamente com as t?cnicas de caracteriza??es FRX, an?lise granulom?trica e as micrografias provenientes do MEV/FEG e EDS confirmaram a adequada impregna??o da prata nos ?xidos. Atrav?s da espectrometria de emiss?o ?ptica com plasma- ICP-OES foi revelado que todas as amostras analisadas apresentaram uma quantidade de prata inferior ao limite de detec??o LD<0,50mg/L, atendendo aos teores m?ximos estabelecidos pelas normas vigentes, quanto a toxidade ? sa?de e ao meio ambiente. / The progressive demand for water has made the treatment and reuse of effluents a subject of worldwide relevance. Considering this situation, the use of nanometric materials have been investigated in order to obtain nanocomposites with anti-bacterial properties. In the search for these new materials, several methodologies and preparation techniques have been developed with the purpose of controlling the shapes and the sizes of the particles to, consequently, improve and optimize their properties. This work consists in the achievement, characterization and antibacterial evaluation of nanocomposites obtained by the impregnation of silver (Ag) in commercial alumina (Y-Al2O3) and zinc oxide (ZnO) by different synthesis routes: microwave-assisted hydrothermal method, sonochemical, and an association of sonochemical and hydrothermal methods, intended to the disinfection of wastewater. A comparative study was performed between the Y-Al2O3 and ZnO nanoparticles, synthesized by sonochemical and microwave-assisted hydrothermal methods, investigating the influence of the composition and the distribution of the particle size on the properties of these. Impregnations of 4%, 8%, 12% and 16% of Ag in Y-Al2O3 and in ZnO were tested. The nanoparticles were applied in an effluent coming from a compact WTP (Wastewater Treatment Plant), after the secundary treatment stage, through bacteriological analyzes, and then the efficiency in the removal of pathogenic indicators of contamination was evaluated. The results concerning the use of the ZnO nanocomposite impregnated with 8% Ag, in the ratio of 0,3g/300mL, for a calculated time of 30 minutes, showed an eficiency of 99,99% in the removal of total coliforms, thermotolerant coliforms and Escherichia coli, reaching standards equal or superior to the already established techniques of disinfection. The network parameters of the nanocomposites obtained through XRD, together with the FRX characterization techniques, particle size analysis and the micrographs from the SEM/FEG and EDS confirmed the adequate impregnation of silver in the oxides. The ICP-OES plasma optical emission spectrometry revealed that all the analyzed samples showed a silver quantity below the detection limit LD<0.50 mg/L, complying the maximum levels established by the current standards, regarding the toxicity to health and the environment.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/23497 |
| Date | 27 April 2017 |
| Creators | Moreira, Micheline Dami?o Dias |
| Contributors | 06296687877, http://lattes.cnpq.br/2365059843175411, Ara?jo, Andr? Luis Calado, 37695045268, http://lattes.cnpq.br/7133712883742750, Menezes, Carla Gracy Ribeiro, 90456017453, Motta, Fabiana Villela da, 24779953839, http://lattes.cnpq.br/9918299069511517, Delmonte, Mauricio Roberto Bomio, 27816279841, http://lattes.cnpq.br/9558299312183852, Paskocimas, Carlos Alberto |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM CI?NCIA E ENGENHARIA DE MATERIAIS, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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