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

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-03-17T19:14:06Z No. of bitstreams: 1 WanessaPaulinoNevesSilva_TESE.pdf: 3403045 bytes, checksum: 8869859d88222685309861913f92b119 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-17T22:41:32Z (GMT) No. of bitstreams: 1 WanessaPaulinoNevesSilva_TESE.pdf: 3403045 bytes, checksum: 8869859d88222685309861913f92b119 (MD5) / Made available in DSpace on 2017-03-17T22:41:32Z (GMT). No. of bitstreams: 1 WanessaPaulinoNevesSilva_TESE.pdf: 3403045 bytes, checksum: 8869859d88222685309861913f92b119 (MD5) Previous issue date: 2016-12-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A sustentabilidade ambiental tem sido alvo de interesse e preocupa??o nas ind?strias, principalmente devido ? gera??o de efluentes. Como os compostos fen?licos s?o t?xicos aos seres vivos, o teor m?ximo de 0,5 ppm ? considerado como concentra??o limite para lan?amentos em corpos de ?gua doce pela Resolu??o Federal CONAMA n?. 430 de 2011. No processo de tratamento desses efluentes, a extra??o l?quido-l?quido ? o processo mais econ?mico para a recupera??o do fenol, pois consome pouca energia, mas, na maioria das vezes, utiliza um solvente org?nico que pode acarretar s?rios problemas ambientais. Alguns estudos comprovam a viabilidade da utiliza??o de tensoativos n?o i?nicos em substitui??o aos solventes org?nicos. O objetivo principal deste trabalho foi estudar o processo de extra??o de fenol de efluentes aquosos utilizando como agente extrator os tensoativos n?o i?nicos nonilfenol etoxilados com grau de etoxila??o: 8; 9,5; 10; 11 e 12. Avaliou-se algumas propriedades do processo, como o ponto de nuvem (PN), concentra??o miclar criticar (c.m.c.) dos tensoativos, termodin?mica de miceliza??o, efeito da concentra??o de sal (Xsal), concentra??o de tensoativo (Xt), concentra??o de fenol (Xf) e grau de etoxila??o da mol?cula de tensoativo (EO), bem como os par?metros do processo de extra??o: efici?ncia de extra??o, raz?o volum?trica das fases, fator de concentra??o e coeficiente de parti??o. Os resultados mostraram que o PN dos tensoativos ? diretamente influenciado pela quantidade de fenol e sais presentes no efluente. A t?cnica de planejamento experimental mostrou-se eficiente no desenvolvimento de modelos matem?ticos capazes de prever o PN dos tensoativos e na otimiza??o das vari?veis visando um baixo custo energ?tico (diminui??o do PN). As condi??es para se obter os menores valores de PN ? Xsal = 0,2%, Xt = 0,5% e EO = 10. Os ensaios para determina??o da c.m.c. e an?lise termodin?mica de miceliza??o permitiram verificar que o aumento da temperatura tende a diminuir a c.m.c. dos tensoativos, o processo de miceliza??o ? espont?neo e exot?rmico para todos os tensoativos e temperaturas estudados. A efici?ncia de remo??o de fenol dos sistemas foi satisfat?ria e, em alguns casos, superior a 95%, apesar do elevado percentual do volume da fase coacervato. A modelagem e an?lise estat?stica dos dados experimentais geraram modelos capazes de descrever o processo, estimando a efici?ncia de remo??o e os par?metros em fun??o da composi??o do sistema. Portanto, a utiliza??o de tensoativos n?o i?nicos nonilfenol etoxilados propostos representam uma alternativa concreta na remo??o de fenol de efluentes aquosos, com menor risco ambiental que os sistemas convencionais utilizados na ind?stria. / Environmental sustainability has been the subject of interest and concern in the industry, mainly due to the generation of waste. As the phenolic compounds are toxic to aquatic organisms, the maximum level of 0.5 ppm is considered as concentration limit for releases in freshwater bodies by the Federal CONAMA Resolution no. 430 2011. In the process of treatment of these effluents, liquid-liquid extraction is the most economical process for the recovery of phenol, because it consumes little energy, but most often implements an organic solvent that can cause serious environmental problems. Some studies demonstrate the feasibility of using non-ionic surfactants to replace organic solvents. The main objective of this work was to study the process of wastewater phenol extraction using as extracting agent non-ionic surfactants nonylphenol ethoxylat. It was evaluated several properties such as the cloud point remove and, critical micelle concentration (c.m.c.) of surfactants micellization thermodynamic, effect of salt concentration (Xsal), surfactant concentration (Xt), phenol concentration (Xf) and ethoxylation degree of surfactant (EO) as well as the parameters of the extraction process. The results shows that the cloud point (PN) of the surfactants is directly affected by the amount of phenol and salts present in the effluent. The experimental design technique was efficient in the development of mathematical models capable of predicting the PN of surfactants and optimization of variables aimed a low energy cost (reduction of PN). The conditions to obtain the lowest value PN is Xsal = 0.2%, Xt = 0.5 and EO = 10. Assays for determining the c.m.c. and micellization thermodynamic analysis allowed to verify that the increase in temperature tends to decrease c.m.c. of surfactants, the micellization is a spontaneous and exothermic process for all temperatures studied and surfactants. The phenol removal efficiency of the systems was satisfactory and in some cases greater than 95%, despite the high percentage of the volume of coacervate phase. The modeling and statistical analysis of experimental data generated models capable of describing and predicting the removal efficiency and the process parameters depending on the composition of the system. Therefore, the remover use of non-ionic surfactants nonylphenol ethoxylate represent a practical alternative for phenol removal from wastewater, resulting in less environmental risks than conventional systems used in industry.