• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • 1
  • Tagged with
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 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

Influ?ncia da densidade de carga e da massa molar da poliacrilamida na reologia de sistemas microemulsionados

Barros, Rosemiro Marinho 07 January 2014 (has links)
Made available in DSpace on 2014-12-17T15:42:14Z (GMT). No. of bitstreams: 1 RosemiroMB_DISSERT.pdf: 2340991 bytes, checksum: c71ab28274a335ce511c0a85fd6c1157 (MD5) Previous issue date: 2014-01-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The knowledge of the rheological behavior of microemulsionated systems (SME) is of fundamental importance due to the diversity of industrial applications of these systems. This dissertation presents the rheological behavior of the microemulsionated system formed by RNX 95/alcohol isopropyl/p-toulen sodium sulfonate/kerosene/distilled water with the addition of polyacrylamide polymer. It was chosen three polymers of the polyacrylamide type, which differ in molar weight and charge density. It was studied the addition of these polymers in relatively small concentration 0,1% in mass and maximum concentration of 2,0%. It was made analysis of flow to determine the appearing viscosities of the SME and rheological parameters applying Bingham, Ostwald de Waale and Herschell-Buckley models. The behavior into saline environment of this system was studied for a solution of KCl 2,0%, replacing the distilled water. It was determined the behavior of microemulsions in relation with the temperature through curves of flow in temperatures of 25 to 60?C in variations of 5?C. After the analysis of the results the microemulsion without the addition of polymer presented a slight increase in its viscosity, but it does not mischaracterize it as a Newtonian fluid. However the additive systems when analyzed with low concentration of polymer adjusted well to the applied models, with a very close behavior of microemulsion. The higher concentration of the polymer gave the systems a behavior of plastic fluid. The results of the temperature variation point to an increase of viscosity in the systems that can be related to structural changes in the micelles formed in the own microemulsion without the addition of polymer / O conhecimento do comportamento reol?gico de sistemas microemulsionados (SME) ? de fundamental import?ncia, devido ? diversidade de aplica??es industriais desses sistemas. Esse trabalho apresenta o comportamento reol?gico do sistema microemulsionado formado por RNX 95/?lcool isoprop?lico/p-tolueno sulfonato de s?dio/Querosene/?gua destilada com a adi??o do pol?mero poliacrilamida. Foram escolhidos tr?s pol?meros do tipo poliacrilamida, que diferem quanto a massa molar e sua densidade de carga. Estudou-se a adi??o desses pol?meros em concentra??o relativamente baixa 0,1% em massa e concentra??o m?xima de 2,0%. Foram realizadas an?lises de escoamento para a determina??o das viscosidades aparente dos SME e par?metros reol?gicos aplicando os modelos de Bingham, Ostwald de Waale e Herschell-Buckley. O comportamento em meio salino desse sistema foi estudado para uma solu??o de KCl 2,0%, em substitui??o ? ?gua destilada. Foi determinado o comportamento das microemuls?es em rela??o ? temperatura atrav?s de curvas de escoamento a temperaturas de 25 a 60?C com varia??es de 5?C. Ap?s an?lise dos resultados a microemuls?o sem adi??o de pol?mero apresentou um ligeiro aumento em sua viscosidade, mas o que n?o a descaracteriza como um fluido newtoniano. Os sistemas aditivados quando analisados com concentra??o baixa de pol?mero ajustaram-se bem aos modelos aplicados, com comportamento muito pr?ximo da microemuls?o. J? a concentra??o mais elevada de pol?mero deu aos sistemas comportamento de fluido pl?stico. Os resultados da varia??o de temperatura apontam para um aumento na viscosidade dos sistemas que pode estar relacionado a mudan?as estruturais nas micelas formadas na pr?pria microemuls?o sem adi??o de pol?mero
2

Devenir des floculants à base de polyacrylamide dans un site de granulat : interactions avec les solides naturels et photodégradation / The fate of polyacrylamide based floculants in aggregate quarry : interactions with natural solids and photodegradation

Mnif, Ines 03 July 2015 (has links)
Les floculants à base de polyacrylamide (PAM) sont produits à partir du monomère toxique : l’acrylamide (AMD) et peuvent en contenir des quantités résiduelles (jusqu’à 0,1% en Europe). Après utilisation pour faciliter la séparation solide/liquide des eaux de procédés dans les industries de granulat, ces floculants sont stockés avec les boues de décantation dans des lagunes à partir desquelles une dissémination de l’AMD et du PAM vers les eaux de surface ou les eaux souterraines peut avoir lieu. Dans ces travaux de thèse, les interactions du PAM et de l’AMD avec des particules de boue et des phases argileuses (kaolinite et illite, utilisées pour étanchéifier les lagunes de décantation) ont été étudiées. Pour pouvoir quantifier correctement l’AMD, une méthode d’analyse basée sur la HPLC/MS/MS en injection directe a été développée. Cette méthode a été validée avec les normes Afnor NF T 90-210 et NF T 90-220 avec une limite de quantification égale à 1 µg/L. L’étude de l’interaction de l’AMD avec des particules de boue d’un site de granulat et deux argiles (kaolinite et illite) a mis en évidence une faible adsorption de l’AMD sur ces phases solides (<10%), indépendante du temps, de la concentration en AMD et du pH. Inversement, le PAM s’adsorbe fortement et irréversiblement sur la boue, la kaolinite et l’illite avec une cinétique rapide de 1er ordre. Les isothermes d’adsorption sont bien corrélées avec les modèles de Langmuir et de Freundlich. Les quantités d’adsorption du PAM sont indépendantes du pH des suspensions mais fortement impactées par la force ionique qui influence les interactions électrostatiques entre le PAM et les surfaces solides. / Polyacrylamide (PAM) based floculants are produced from the highly toxic acrylamide (AMD) monomer and can contain residual amounts (up to 0.1% in Europe) of AMD. After they are used to facilitate liquid/solid separation of process water in aggregate quarries, PAM floculants are stored, with the sewage sludge, in decantation lagoons. Dissemination of AMD and PAM to groundwater and surface water from these lagoons can occur. In this work, we aimed to study the interactions of AMD and PAM with sludge particles and clays (kaolinite and illite used for decantation lagoon sealing) from aggregate quarry. To correctly quantify the AMD, analytical method based on HPLC/MS/MS with direct injection was developed. This method was validated according to the Afnor guidelines (NF T 90-210 and NF T 90-220) with a limit of quantification of 1 µg/L. Results of AMD adsorption experiments showed a low adsorption of AMD to sludge and clay (kaolinite and illite) particles, which is independent of time, AMD concentration and pH. Inversely, PAM was found to adsorb strongly and irreversibly to sludge, kaolinite and illite with a rapid kinetic of adsorption which consists of first order kinetic. Adsorption isotherms are well correlated with Langmuir and Freundlich models. PAM adsorption quantities are independent on the pH of suspensions, but are strongly impacted by the ionic strength which affects electrostatic interactions between PAM and solid surfaces.

Page generated in 0.0342 seconds