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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Caracteriza??o f?sico-qu?mica de sistemas micelares

Silva, Gustavo Thalmer de Medeiros 23 July 2014 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-01-04T20:23:54Z No. of bitstreams: 1 GustavoThalmerDeMedeirosSilva_DISSERT.pdf: 1162782 bytes, checksum: ed5902caebeb3cd020717eb3292a6820 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-01-11T18:19:26Z (GMT) No. of bitstreams: 1 GustavoThalmerDeMedeirosSilva_DISSERT.pdf: 1162782 bytes, checksum: ed5902caebeb3cd020717eb3292a6820 (MD5) / Made available in DSpace on 2016-01-11T18:19:26Z (GMT). No. of bitstreams: 1 GustavoThalmerDeMedeirosSilva_DISSERT.pdf: 1162782 bytes, checksum: ed5902caebeb3cd020717eb3292a6820 (MD5) Previous issue date: 2014-07-23 / Os processos de miceliza??o e adsor??o dos tensoativos dodecil sulfato de s?dio, cloreto de dodecilam?nio e hexaetileno glicol mono-n-dodecil ?ter em interface l?quido-g?s foram estudados a partir de medidas de tens?o superficial em meio aquoso e em NaCl 0,1 mol/L em temperaturas de 25, 33 e 40 ?C. A partir destes dados, a concentra??o micelar cr?tica e par?metros termodin?micos de miceliza??o e adsor??o foram determinados, a fim de elucidar os comportamentos de miceliza??o e adsor??o para esses tensoativos nos meios propostos. Para a determina??o dos par?metros termodin?micos de adsor??o, foram utilizadas as equa??es das isotermas de Gibbs e de Langmuir. Os valores de ?m?x determinados pelas diferentes equa??es foram correlacionados para a explica??o dos resultados. A temperatura e salinidade foram analisadas quanto ?s suas influ?ncias no processo de miceliza??o e adsor??o, e os resultados foram explicados baseados nas intera??es intermoleculares. Os valores de ?Gmic confirmaram que a forma??o micelar para os tensoativos estudados ocorre espontaneamente / The process of adsorption and micellization of the surfactants sodium dodecyl sulfate, dodecylammonium chloride and hexaethylene glycol mono-n-dodecyl ether in water-air interface has been studied using measurements of surface tension in aqueous media and NaCl 0.1 mol/L in temperatures of 25, 33 and 40 ?C. From these data, critical micelle concentrations and thermodynamic parameters of micellization and adsorption were determined in order to elucidate the behaviors of micellization and adsorption for these surfactants in the proposed medium. For the determination of the thermodynamic parameters of adsorption we utilized the equations of isotherms of Langmuir and Gibbs. ?m?x values determined by the different equations were correlated to the explanation of results. Temperature and salinity were analyzed in terms of their influence on the micellization and adsorption process, and the results were explained based on intermolecular interactions. The values of ?Gmic have confirmed that the micelle formation for the surfactants studied occurs spontaneously

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