• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • 3
  • 1
  • 1
  • Tagged with
  • 9
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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

Le général Berthelot et l'action de la France en Roumanie et en Russie méridionale, 1916-1918 : genèse, aspects diplomatiques, militaires et culturels avec leurs incidences, prolongements et perspectives /

Grandhomme, Jean-Noël, January 1999 (has links)
Th. doct.--Hist.--Paris 4, 1998. / En appendice, choix de documents. Bibliogr. p. 1077-1120. Résumé en français et en anglais.
2

Estudos da modificação da resina não-iônica Amberlite XAD-7 com monoetanolamina (MEA) para retenção de espécies de S(IV) / Studies about the loading of monoethanolamine (MEA) onto the non-ionic Amberlite XAD-7 resin for retention of S(IV) species

Ferreira, Flavia Alves 30 August 2007 (has links)
A monoetanolamina (MEA) é um composto bifuncional pertencente à classe dos amino-álcoois, muito utilizado em processos industriais envolvendo a remoção de gases ácidos como SO2 , CO2 e H2S. A resina Amberlite XAD-7 é uma resina não-iônica de polaridade intermediária muito utilizada em procedimentos de pré-concentração de compostos orgânicos e íons metálicos. Neste trabalho, estudou-se a interação entre a superfície da resina XAD-7 e a MEA. Massas conhecidas da resina foram colocadas em contato com soluções de MEA em concentrações conhecidas, sob agitação durante certo intervalo de tempo. A quantidade de MEA adsorvida foi calculada considerando-se a diferença entre a concentração inicial e a concentração remanescente no sobrenadante, ambas obtidas a partir de medidas de absorbância, com utilização da reação de Berthelot modificada. Modelos cinéticos de pseudo-primeira e -segunda ordens, além do modelo de difusão intra-partícula, foram aplicados aos dados experimentais obtidos no estudo cinético. Entre estes modelos aplicados, o de pseudo-segunda ordem apresentou excelente ajuste aos dados experimentais. O estudo realizado em um determinado tempo de contato e variando-se a concentração inicial de MEA forneceu resultados experimentais que foram aplicados a três modelos de isotermas (Langmuir, Freundlich e Dubinin-Radushkevich). Destes ajustes, que mostraram excelente concordância, foram obtidos diferentes parâmetros termodinâmicos que definiram algumas características do processo de adsorção. Finalmente, estudos preliminares evidenciaram a retenção de SO32- na superfície da resina XAD-7 modificada com MEA, mostrando a possibilidade da utilização da XAD- 2 7/MEA para extração de SO32- presente em soluções ou de SO2 recolhido em solução alcalina. / Monoethanolamine (MEA) is a bifunctional compound which belongs to the amino- alcohol group, and it is widely used in industrial \"sweetening process\", which is based on the acidic gas (such as SO2 , CO2 and H2S) absorption. Amberlite XAD-7 is a non-polar resin with an intermediate polarity used to pre-concentrate organic compounds and transition metals. In this work, the interaction between the resin surface and MEA was studied. Known amounts of the resin were kept in contact with aqueous solutions of MEA and shaked under a constant rotation and during some defined intervals of time. The amount of adsorbed MEA was calculated as the difference between the initial concentration and remained concentration in the supernatant solution, which was determined applying the Berthelot´s reaction and the spectrophotometry. Kinetic models of pseudo-first and -second orders and intra-particle diffusion model were applied on experimental data collected from the kinetic study. Among these methods, the pseudo-second order model fulled fit on those experimental data. The experiments carried out under a constant time, but by changing the initial MEA concentration, led to other experimental data which were applied to three different isotherm models (Langmuir, Freundlich e Dubinin-Radushkevich). Each model showed a good fit, and for each one, different thermodynamic parameters were calculated and used to describe some adsorption characteristics. Finally, preliminary studies on the retention of SO32- onto the resin surface, previously modified with MEA, showed the possibility to extract SO32- found in aqueous solutions or SO2 recovered in alkaline media.
3

Estudos da modificação da resina não-iônica Amberlite XAD-7 com monoetanolamina (MEA) para retenção de espécies de S(IV) / Studies about the loading of monoethanolamine (MEA) onto the non-ionic Amberlite XAD-7 resin for retention of S(IV) species

Flavia Alves Ferreira 30 August 2007 (has links)
A monoetanolamina (MEA) é um composto bifuncional pertencente à classe dos amino-álcoois, muito utilizado em processos industriais envolvendo a remoção de gases ácidos como SO2 , CO2 e H2S. A resina Amberlite XAD-7 é uma resina não-iônica de polaridade intermediária muito utilizada em procedimentos de pré-concentração de compostos orgânicos e íons metálicos. Neste trabalho, estudou-se a interação entre a superfície da resina XAD-7 e a MEA. Massas conhecidas da resina foram colocadas em contato com soluções de MEA em concentrações conhecidas, sob agitação durante certo intervalo de tempo. A quantidade de MEA adsorvida foi calculada considerando-se a diferença entre a concentração inicial e a concentração remanescente no sobrenadante, ambas obtidas a partir de medidas de absorbância, com utilização da reação de Berthelot modificada. Modelos cinéticos de pseudo-primeira e -segunda ordens, além do modelo de difusão intra-partícula, foram aplicados aos dados experimentais obtidos no estudo cinético. Entre estes modelos aplicados, o de pseudo-segunda ordem apresentou excelente ajuste aos dados experimentais. O estudo realizado em um determinado tempo de contato e variando-se a concentração inicial de MEA forneceu resultados experimentais que foram aplicados a três modelos de isotermas (Langmuir, Freundlich e Dubinin-Radushkevich). Destes ajustes, que mostraram excelente concordância, foram obtidos diferentes parâmetros termodinâmicos que definiram algumas características do processo de adsorção. Finalmente, estudos preliminares evidenciaram a retenção de SO32- na superfície da resina XAD-7 modificada com MEA, mostrando a possibilidade da utilização da XAD- 2 7/MEA para extração de SO32- presente em soluções ou de SO2 recolhido em solução alcalina. / Monoethanolamine (MEA) is a bifunctional compound which belongs to the amino- alcohol group, and it is widely used in industrial \"sweetening process\", which is based on the acidic gas (such as SO2 , CO2 and H2S) absorption. Amberlite XAD-7 is a non-polar resin with an intermediate polarity used to pre-concentrate organic compounds and transition metals. In this work, the interaction between the resin surface and MEA was studied. Known amounts of the resin were kept in contact with aqueous solutions of MEA and shaked under a constant rotation and during some defined intervals of time. The amount of adsorbed MEA was calculated as the difference between the initial concentration and remained concentration in the supernatant solution, which was determined applying the Berthelot´s reaction and the spectrophotometry. Kinetic models of pseudo-first and -second orders and intra-particle diffusion model were applied on experimental data collected from the kinetic study. Among these methods, the pseudo-second order model fulled fit on those experimental data. The experiments carried out under a constant time, but by changing the initial MEA concentration, led to other experimental data which were applied to three different isotherm models (Langmuir, Freundlich e Dubinin-Radushkevich). Each model showed a good fit, and for each one, different thermodynamic parameters were calculated and used to describe some adsorption characteristics. Finally, preliminary studies on the retention of SO32- onto the resin surface, previously modified with MEA, showed the possibility to extract SO32- found in aqueous solutions or SO2 recovered in alkaline media.
4

L'humour, instrument journalistique dans l'oeuvre d'Hector Berthelot (1877-1895)

Gosselin, Sophie January 2007 (has links) (PDF)
L'histoire de la presse humoristique est un champ de la discipline qui a été redécouvert récemment. C'est pourquoi, jusqu'ici, l'oeuvre d'Hector Berthelot, rédacteur et éditeur de journaux satiriques à Montréal entre 1877 et 1895, a principalement été analysée sous l'angle de l'histoire de l'art. Mais cet intérêt pour l'aspect graphique des caricatures éclipse leur contenu, en plus de ne pas tenir compte du texte, qui constitue pourtant l'essentiel du travail de l'humoriste. Le présent mémoire se penche donc spécifiquement sur le propos des journaux de Berthelot. Plus précisément, il s'agit de déterminer les fonctions occupées par l'humour dans son travail journalistique. Pour ce faire, nous avons analysé les six titres dont il a été le rédacteur et l'éditeur, procédant par un examen général des journaux ainsi que par l'étude approfondie d'un échantillon représentatif. Dans un premier temps, nous brossons un portrait de l'homme et de son époque à l'aide d'extraits des différents journaux de Berthelot. Nous abordons son parcours, ses différentes feuilles, les conditions de production générales des journaux canadiens-français au XIXe siècle ainsi que la place spécifique de la presse satirique. Par la suite, nous identifions deux fonctions de l'humour dans l'oeuvre de Berthelot. La première est sa volonté d'indépendance, lui qui a évolué à l'époque de la presse d'opinion, dans un milieu très polarisé. Ne gagnant pas la faveur de son lectorat par une allégeance politique, il a eu recours à la blague pour le séduire. Ce procédé lui a donc servi à se faire pardonner de ne pas suivre l'une des principales normes régissant la presse de son temps. En s'exprimant par l'humour, notamment en employant des personnages dans des mises en scène satiriques, il a pu tenir ce discours inhabituel tout en conservant la sympathie du public. Le second objectif du ton ludique utilisé par Berthelot est de nature pédagogique. À une époque où l'analphabétisme connaissait une régression significative, il a voulu rendre ses journaux accessibles aux classes moins instruites. Il a donc employé des personnages et des images humoristiques accessibles, notamment en ayant recours aux références traditionnelles canadiennes-françaises, son public étant en grande partie issu de l'exode rural. Il a placé les décideurs de son époque dans des situations familières pour les mettre à la portée de tous, et ainsi favoriser l'intérêt populaire pour les questions politiques. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Hector Berthelot, Histoire, Journalisme, Humour, Québec 1877-1895.
5

Multi-capteurs chimiques de chloramines et de chloroforme à transduction optique. Application à la surveillance de la qualité de l’air dans les piscines / Multi-chemical sensor for the optical detection of chloramines and chloroform. Application for monitoring the air quality in pools

Nguyen, Trung Hieu 04 February 2014 (has links)
Le chlore est largement utilisé pour ses propriétés bactéricides dans les piscines. Dans les eaux de piscine, le chlore réagit avec les matières azotées et carbonées générées par l’activité humaine (sueur, salive, urine, peau) pour former divers composés toxiques tels que la monochloramine (NH2Cl), la dichloramine (NHCl2), le trichlorure d'azote (NCl3), le chloroforme (CHCl3), etc… qui se retrouvent dans l’atmosphère. La détection et la quantification de ces composés volatils à des teneurs ppb (partie par milliard) est un réel besoin afin de contrôler la qualité de l’air des piscines. Cependant il n’existe pas à ce jour des appareils à la fois sensibles et peu coûteux.L’objectif de ce travail de thèse est d’élaborer des capteurs chimiques colorimétriques, sensibles, sélectifs et peu coûteux de la monochloramine, du trichlorure d’azote et du chloroforme. Dans ce but, nous avons mis au point des capteurs chimiques réalisés à partir de matrices nanoporeuses de silicate dopée des réactifs. Ainsi le capteur de NCl3 dopé de NaI et d’amylose permet de mesurer de faibles teneurs de NCl3 (5 ppb à 180 ppb) dans les atmosphères humides (50-80% HR) des piscines. Grâce au changement rapide de couleur, de transparent à rose-violet, visible à l’œil nu, le capteur de NCl3 permet de surveiller la qualité de l’air dans les piscines. Le capteur sélectif de NH2Cl est basé sur la réaction de Berthelot. La matrice de silicate nanoporeuse dopée de nitroprussiate de sodium et de phénol en milieu alcalin, initialement transparente, devient bleue lors d’une exposition à NH2Cl gazeux. Ce capteur permet de détecter NH2Cl dans la gamme de 60 à 250 ppb dans une atmosphère très humide (≈ 80%). Utilisé pour la sonder la qualité des eaux de piscine, il permet de mesurer NH2Cl dans l’eau avec une limite de détection de 0,1 µmol•L-1. Une étude préliminaire de la détection de CHCl3 a également été entreprise pour déterminer les molécules-sonde aptes à réagir avec le chloroforme en formant des produits colorés. Les réactifs de la réaction de Fujiwara ont été sélectionnés. L’étude de la réactivité de la 2,2’-bipyridine en solution en présence d’une base forte a permis de mettre en évidence la formation simultanée de deux composés colorés, dont la formation dépend de la nature de l’environnement réactionnel. / In swimming-pools, chlorine is used as a disinfectant to minimize the risk to users from microbial contaminants. In water, chlorine reacts with nitrogen compounds generated by human activity like saliva, sweat, urine and skin, leading to the formation of toxic compounds, such as monochloramine (NH2Cl), dichloramine (NHCl2), nitrogen trichloride (NCl3), chloroform (CHCl3), etc… The detection and the quantification of these volatile compounds at ppb level (part per billion) is an important and significant challenge to be able to monitor the air quality in swimming pool. Or, there is currently no commercially available and low-cost system which can instantaneously measure at ppb concentrations.The aim of this research is to develop a cheap, sensitive and selective chemical and colorimetric sensors of monochloramine, nitrogen trichloride and chloroform. For this purpose, we developed chemical sensors based on the use of nanoporous silicate matrices doped with probe-molecules. The NCl3 sensor doped with NaI and amylose can detect NCl3 at ppb level (5 ppb – 180 ppb) in humid atmospheres (from 50% to 80% relative humidity) at ambient pool temperatures. Due to the fast change of color, visible with naked eyes, these sensors can be used to detect peaks of pollution and to monitor the air quality of indoor pools. The NH2Cl selective sensor is based on the Berthelot reaction. The nanoporous silicate matrices doped with sodium nitroprusside and phenol in an alkaline medium, turn from transparent to blue upon exposure to gaseous NH2Cl. This sensor can detect NH2Cl in the range from 60 to 250 ppb in a very humid atmosphere (≈ 80%). Used to probe the quality of pool water, this sensor can detect NH2Cl in water with a detection limit of 0,1 µmol•L-1. A preliminary study of the CHCl3 detection was also conducted to identify probe-molecules capable of reacting with chloroform to form colored products. The reagents of the Fujiwara reaction were selected. The study of the 2,2’-bipyridine reactivity in solution in the presence of a strong base allowed highlighting the simultaneous formation of two colored compounds, whose formation depends on the nature of the reaction environment.
6

Évolution du tissu urbain de Québec et de ses espaces publics : analyse morphologique de trois places /

Kotzev, Emil. January 1997 (has links)
Thèse (M. Arch.)--Université Laval, 1997. / Bibliogr.: f. 142-148. Publié aussi en version électronique.
7

A Cooperativa de Ensino de Mme Curie: relações entre ciência e educação em meio ao debate sobre o ensino francês entre o final do século XIX e o início do século XX / The Co-operative Education of the Mme Curie: relationship between science and education amid debate about the French education in the late nineteenth century and early twentieth century

Tonetto, Sonia Regina 19 March 2014 (has links)
Made available in DSpace on 2016-04-28T14:16:19Z (GMT). No. of bitstreams: 1 Sonia Regina Tonetto.pdf: 1372040 bytes, checksum: 8041dda5cc94d8c48e9bf949419c38de (MD5) Previous issue date: 2014-03-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work aims to analyze the ideas about methods of teaching science in the early twentieth advocated by prominent scientists as Marcellin Berthelot, Paul Langevin and Henri Poincaré and the important contribution of these scientists in the reform of French teaching, 1902. Furthermore, we sought to understand the difficulties faced in teaching in French schools of that period, we sought to also to understand what these scientists believed to be the ideal science teaching method and the influence of positivist ideas in these discussions. We analyzed in particular the role of Co-operative Education of Mme Curie (1907-1908) and the objectives of the group of teachers, including Paul Langevin, which was involved in the discussions on the reform. This work was developed from the analysis of documents filed at the Institut Curie and at Bibliothèque Nationale de France, texts and books written by scholars and scientists, with direct and indirect participation in the reform, records of lectures, articles and manuscripts of the children who participated in the cooperative, as Isabelle Chavannes and Irène Curie / Este trabalho tem como objetivo analisar as ideias sobre métodos de ensino de ciências, no início do século XX, defendidas por cientistas de destaque, como Marcellin Berthelot, Paul Langevin e Henri Poincaré e a importante participação desses cientistas na reforma do ensino francês de 1902. Além disso, procurou-se entender as dificuldades enfrentadas no ensino nas escolas francesas daquele período, compreendendo o que esses cientistas acreditavam ser o método ideal para o ensino de ciências e a influência das ideias positivistas nessas discussões. Analisa-se em particular o papel da Cooperativa de Ensino de Mme Curie (1907-1908) e os objetivos do grupo de professores que, como Paul Langevin, se envolveu nos debates sobre a reforma. Este trabalho foi desenvolvido a partir da análise de documentos depositados no Institut Curie e na Bibliothèque Nationale de France, Paris, textos da época, livros escritos por estudiosos e cientistas com participação direta e indireta na reforma, registros de conferências, artigos publicados, manuscritos das crianças que participaram da cooperativa, como Isabelle Chavannes e Irène Curie
8

Surface Free Energy Evaluation, Plasma Surface Modification And Biocompatibility Studies Of Pmma

Ozcan, Canturk 01 August 2006 (has links) (PDF)
PMMA is a widely used biomaterial especially in the fields of orthopedia, orthodontia and ophthalmology. When biocompatibility is considered, modification of the biomaterials&amp / #8217 / surface may be needed to optimize interactions of the biomaterial with the biological environment. After the surface modifications one of the most important changes that occur is the change in the surface free energy (SFE). SFE is an important but an obscure property of the material and evaluation methods with different assumptions exist in the literature. In this study, SFE of pristine and oxygen plasma modified PMMA films were calculated by means of numerous theoretical approaches (Zisman, Saito, Fowkes, Berthelot, Geometric and Harmonic Mean and Acid-Base) using numerous liquids and the results were compared to each other to elucidate the differences of methods. Dispersive, polar, acidic and basic components of the SFE were calculated by the use of different liquid couples and triplets with the application of Geometric and Harmonic mean methods and Acid-Base approach. The effect of SFE and the components of SFE on the cell attachment efficiencies were examined by using fibroblast cells. It was observed that with the treatment of oxygen plasma, cell attachment capability and hydrophilicity of PMMA surfaces were altered depending on the applied power and duration of the plasma.
9

Revalorización de lodos resultantes del pasivado de aluminio por oxidación anódica mediante su utilización en la síntesis de zeolitas NaP1 y LTA

Peñafiel Villarreal, Fausto 10 June 2022 (has links)
[ES] La normativa ambiental potencia la revalorización de los residuos industriales y motiva su utilización como materias primas para la obtención de nuevos materiales útiles, en lugar de que dichos residuos sean depositados en rellenos, que a la postre pueden generar pasivos ambientales. Dentro de este contexto se planificó la síntesis de la zeolita NaP1 código GIS, de amplia utilización en el campo ambiental para la descontaminación de aguas residuales, particularmente polutas con metales pesados y, la síntesis de la zeolita A código LTA, con aplicaciones en la industria de detergentes en reemplazo de los fosfatos, causantes de acelerar la eutrofización del agua de lagos; esto utilizando como materia prima los residuos industriales provenientes de los procesos y operaciones unitarias del pasivado del aluminio por oxidación electrolítica anódica. La presente investigación se enfoca en la recuperación indirecta del aluminio presente en los residuos industriales de anodizado de aluminio, transfiriéndolo a la estructura cristalina de las zeolitas. El residuo contiene elevadas concentraciones de aluminio, tal como lo prueban los resultados obtenidos mediante microscopía electrónica de barrido SEM (38.9% - 40.42%) y por espectroscopia de absorción atómica con llama AAS (37.16 g/100g); pero es pobre en contenido de silicio (0.93% - 0.74%) determinado por SEM y 1.83 g/100g determinado por AAS. Además, el residuo de anodizado de aluminio contiene concentraciones menores de cationes alcalinos y alcalinotérreos. El contenido de humedad del lodo es de 69.84% (n=28) y su pH cae en el rango 7.7 a 8.3 (1:5 w/v), que lo hace ligeramente alcalino. Se observó que la relación molar Si/Al es significativamente menor que la unidad, de lo cual se infiere que los residuos industriales tal como salen de la planta de tratamiento, no se pueden utilizar para la síntesis de zeolitas. La caracterización de los residuos industriales deshidratados a 100°C por 4 y 24 horas mediante microscopia electrónica de barrido (SEM) y difracción de rayos-X muestran un material básicamente amorfo, sin morfología externa apreciable. La composición fisicoquímica en términos del contenido de aluminio en los lodos de anodizado, permite plantear la recuperación del aluminio y cationes a través de la síntesis de zeolitas, utilizando como materia prima el residuo industrial, enriquecido con silicio proveniente de fuentes externas. Así para sintetizar la zeolita NaP1, código GIS, se enriqueció el lodo de anodizado con silicio proveniente de una solución de silicato de sodio grado analítico. Con la finalidad de identificar la concentración a la que se tiene los mejores resultados, se utilizó como agente de mineralización soluciones de NaOH en concentraciones 0.5M; 1.0M; 1.5M; 2.0M; 2.5M y 3.0M. Se instrumentó el método hidrotermal de síntesis a una temperatura constante de 100°C y 48 horas de tiempo de reacción, utilizando los residuos industriales húmedos. Los materiales obtenidos a las diferentes condiciones de síntesis se han caracterizado mediante difracción de rayos-X y SEM. Así, las concentraciones 1.5M, 2.0M, 2.5M y 3.0M del agente de mineralización NaOH conducen a la síntesis de la zeolita NaP1 código GIS. Sin embargo, el producto obtenido utilizando como agente de mineralización NaOH 1.5M presenta cristales con morfología externa muy bien definida, en forma de esferas de tamaño homogéneo. Este material presenta una relación molar Si/Al de 2.44 y una fórmula teórica 0.98Na2O•Al2O3•4.88SiO2•yH2O. Los materiales obtenidos con concentraciones más altas del agente de mineralización, aun presentando un difractograma de rayos-X correspondiente a la zeolita NaP1, en el microscopio electrónico muestran cristales poco formados y de tamaños muy diferentes. De esto se infiere que el agente de mineralización NaOH 1.5M presenta los mejores resultados en términos de morfología. Utilizando como fuente de enriquecimiento de silicio el silicato de sodio comercial, se sintetizó la zeoli / [CA] La normativa ambiental potència la revaloració dels residus industrials i motiva la seua utilització com a matèries primeres per a l'obtenció de nous materials útils, en lloc que aquests residus siguen depositats en farciments, que fet i fet poden generar passius ambientals. Dins d'aquest context es va planificar la síntesi de la zeolita NaP1 codi GIS, d'àmplia utilització en el camp ambiental per a la descontaminació d'aigües residuals, particularment contaminades amb metalls pesants i, la síntesi de la zeolita A codi LTA, amb aplicacions en la indústria de detergents en reemplaçament dels fosfats, causants d'accelerar l'eutrofització de l'aigua de llacs; això utilitzant com a matèria primera els residus industrials provinents dels processos i operacions unitàries del passivat de l'alumini per oxidació electrolítica anòdica. La present investigació s'enfoca en la recuperació indirecta de l'alumini present en els residus industrials d'anoditzat d'alumini, transferint-ho a l'estructura cristal·lina de les zeolites. El residu conté elevades concentracions d'alumini, tal com ho proven els resultats obtinguts mitjançant microscòpia electrònica d'escombratge SEM (38.9% - 40.42%) i per espectroscòpia d'absorció atòmica amb flama AAS (37.16 g/100g); però és pobre en contingut de silici (0.93% - 0.74%) determinat per SEM i 1.83 g/*100g determinat per AAS. A més, el residu d'anoditzat d'alumini conté concentracions menors de cations alcalins i alcalinoterris. El contingut d'humitat del llot és de 69.84% (n=28) i el seu pH cau en el rang 7.7 a 8.3 (1:5 w/v), que ho fa lleugerament alcalí. Es va observar que la relació molar Si/A l'és significativament menor que la unitat, de la qual cosa s'infereix que els residus industrials tal com ixen de la planta de tractament, no es poden utilitzar per a la síntesi de zeolites. La caracterització dels residus industrials deshidratats a 100 °C per 4 i 24 hores mitjançant microscòpia electrònica d'escombratge (SEM) i difracció de raigs-X mostren un materials bàsicament amorfs, sense morfologia externa apreciable. La composició fisicoquímica en termes del contingut d'alumini en els llots d'anoditzat, permet plantejar la recuperació de l'alumini i cations a través de la síntesi de zeolites, utilitzant com a matèria primera el residu industrial, enriquit amb silici provinent de fonts externes. Així per a sintetitzar la zeolita NaP1, codi GIS, es va enriquir el llot d'anoditzat amb silici provinent d'una solució de silicat de sodi grau analític. Amb la finalitat d'identificar la concentració a la qual es té els millors resultats, es va utilitzar com a agent de mineralització soluciones de NaOH en concentracions 0.5M; 1.0M; 1.5M; 2.0M; 2.5M i 3.0M. Es va instrumentar el mètode hidrotermal de síntesi a una temperatura constant de 100 °C i 48 hores de temps de reacció, utilitzant els residus industrials humits. Els materials obtinguts a les diferents condicions de síntesis s'han caracteritzat mitjançant difracció de raigs-X i SEM. Així, les concentracions 1.5M, 2.0M, 2.5M i 3.0M de l'agent de mineralització NaOH condueixen a la síntesi de la zeolita NaP1 codi GIS. No obstant això, el producte obtingut utilitzant com a agent de mineralització NaOH 1.5M presenta cristalls amb morfologia externa molt ben definida, en forma d'esferes de grandària homogènia. Aquest material presenta una relació molar Si/Al de 2.44 i una fórmula teòrica 0.98Na2O•Al2O3•4.88SiO2•yH2O. Els materials obtinguts amb concentracions més altes de l'agent de mineralització, encara presentant un difractograma de raigs-X corresponent a la zeolita NaP1, en el microscopi electrònic mostren cristalls poc formats i de grandàries molt diferents. D'això s'infereix que l'agent de mineralització NaOH 1.5M presenta els millors resultats en termes de morfologia. Utilitzant com a font d'enriquiment de silici el silicat de sodi comercial, es va sintetitzar la zeolita Linde Tipus A, Codi estructural HISSA (Associació International de zeolite / [EN] Environmental regulations promote the revaluation of industrial waste and encourage its use as raw materials to obtain new valuable materials, instead of such waste being deposited in landfills, which can ultimately generate environmental liabilities. Within this context, the synthesis of the GIS code NaP1 zeolite, widely used in the environmental field for the decontamination of wastewater, particularly polluted with heavy metals, and the synthesis of the LTA code zeolite A, with applications in industry. detergents to replace phosphates, which cause the eutrophication of lake water to accelerate, were planned using as raw material the industrial residues from the processes and unitary operations of aluminum passivation by anodic electrolytic oxidation. This research focuses on the indirect recovery of aluminum present in industrial waste from aluminum anodizing, transferring it to the crystalline structure of zeolites. The residue contains high concentrations of aluminum, as proven by the results obtained by scanning electron microscopy SEM (38.9% - 40.42%) and by atomic absorption spectroscopy with AAS flame (37.16 g/100g); but it is poor in silicon content (0.93% - 0.74%) determined by SEM and 1.83 g/100g determined by AAS. In addition, the aluminum anodizing residue contains lower concentrations of alkali and alkaline earth cations. The moisture content of the mud is 69.84% (n=28) and its pH falls in the range of 7.7 to 8.3 (1:5 w/v), which makes it slightly alkaline. It was observed that the Si/Al molar ratio is significantly less than unity, from which it is inferred that industrial waste as it leaves the treatment plant has to be modified to be used for the synthesis of zeolites. SEM and X-ray diffraction characterization of the aluminum-containing industrial waste dehydrated at 100°C for 4 and 24 hours show basically amorphous materials without appreciable external morphology. The physicochemical composition in terms of the aluminum content in the anodizing sludge allows us to propose the recovery of aluminum through the synthesis of zeolites, using industrial waste as raw material, and enriching it with silicon from external sources. Thus, to synthesize the zeolite NaP1, code GIS, the anodizing sludge was enriched with silicon from an analytical grade sodium silicate solution. To identify the concentration at which the best results are obtained, NaOH solutions at 0.5M concentrations were used as mineralization agents; 1.0M; 1.5M; 2.0M; 2.5M and 3.0M. The hydrothermal synthesis method was implemented at a constant temperature of 100°C and 48 hours of reaction time, using wet industrial waste. The materials obtained at the different synthesis conditions were characterized by X-ray diffraction and SEM. Thus, concentrations of 1.5M, 2.0M, 2.5M, and 3.0M of the mineralizing agent NaOH lead to the synthesis of the zeolite NaP1 code GIS. However, the product obtained using 1.5M NaOH as the mineralization agent presents crystals with a very well-defined external morphology in the form of spheres of homogeneous size. This material has a Si/Al molar ratio of 2.44 and a theoretical formula of 0.98Na2O•Al2O3•4.88SiO2•yH2O. The materials obtained with higher concentrations of the mineralization agent, even presenting an X-ray diffractogram corresponding to zeolite NaP1, show poorly formed crystals of very different sizes. From this, it is inferred that the 1.5M NaOH mineralization agent presents the best results in terms of morphology. Using commercial sodium silicate as the source of silicon enrichment, the Linde Type A zeolite, structural code IZA (International Zeolite Association) LTA, was synthesized. This product is obtained with a weight ratio of wet industrial residue to commercial sodium silicate of 2.6 to 1, using 1.5M NaOH as a mineralization agent at 85°C and a reaction time of 4 hours, resulting in a zeolite A code LTA with Si/Al molar ratio, 1.04 (sample 1A) and Si/Al 1.05 (sample 2A). Taking into account the r / Peñafiel Villarreal, F. (2022). Revalorización de lodos resultantes del pasivado de aluminio por oxidación anódica mediante su utilización en la síntesis de zeolitas NaP1 y LTA [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/183230 / TESIS

Page generated in 0.3695 seconds