This thesis has addressed several of the fundamental challenges in correlating the structure thermal transport properties of complex nanoporous polycrystalline zeolite materials. Two types of zeolite materials, MFI and LTA, were employed in order to investigate the effects of temperature and both the framework and non-framework cations on the thermal conductivity of zeolite. The thermal conductivity values of both materials were measured using a well intergrown zeolite film 3-omega method. The thermal transport mechanisms in these materials were investigated by separately analyzing the contributions of different phonon scattering processes. This thesis represents our progress towards a robust framework for understanding and predicting thermal transport properties of zeolite materials and complex crystals in general. Furthermore, the important roles of boundary and defect scattering, as illustrated in this thesis, also imply that the thermal conductivity of zeolite materials can be tuned by exploiting not only the composition but also the pore structure. In addition, a non-equilibrium molecular dynamics simulation with external force was developed and employed to predict the thermal conductivity of materials. It has shown that this method can accurately predict the thermal conductivity of simple materials, such as argon and quartz; however, it failed to predict the thermal conductivity of complex materials, such as zeolite. This thesis presents possible factors that can explain the phenomena and future recommendations to elucidate this issue.

Made available in DSpace on 2014-12-17T14:07:11Z (GMT). No. of bitstreams: 1 ThiagoC_TESE_PARCIAL.pdf: 936476 bytes, checksum: 8bf6e0f098d614d4feecc4fca3221123 (MD5) Previous issue date: 2013-03-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Different types of heterogeneous catalysts of the silicoaluminophosphate type, (SAPO-5, SAPO-11, SAPO-31, SAPO-34 and SAPO-41), molecular sieves with a: AFI, AEL, ATO, CHA and AFO structure, respectively, were synthesized through the hydrothermal method. Using sources such as hydrated alumina (pseudobohemita), phosphoric acid, silica gel, water, as well as, different types of organic structural templates, such as: cetyltrimethylammonium bromide (CTMABr), di-isopropylamine (DIPA), di-n- propylamine (DNPA) and tetraethylammonium hydroxide (TEOS), for the respective samples. During the preparation of the silicoaluminophosphates, the crystallization process of the samples occurred at a temperature of approximately 200 ? C, ranging through periods of 18-72 h, when it was possible to obtain pure phases for the SAPOs. The materials were furthermore washed with deionized water, dried and calcined to remove the molecules of the templates. Subsequently the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), absorption spectroscopy in the infrared region (FT-IR), specific surface area and thermal analysis via TG/DTG. The acidic properties were determined using adsorption of n-butylamine followed by programmed termodessorption. These methods revealed that the SAPO samples showed a typically weak to moderate acidity. However, a small amount of strong acid sites was also detected. The deactivation of the catalysts was conducted by artificially coking the samples, followed by n-hexane cracking reactions in a fixed bed with a continuous flow micro-reactor coupled on line to a gas chromatograph. The main products obtained were: ethane, propane, isobutene, n-butane, n-pentane and isopentane. The Vyazovkin (model-free) kinetics method was used to determine the catalysts regeneration and removal of the coke / Diferentes tipos de catalisadores heterog?neos do tipo silicoaluminofosf?tico, (SAPO-5, SAPO-11, SAPO-31, SAPO-34 e SAPO-41), peneiras moleculares com estrutura: AFI, AEL, ATO, CHA e AFO, respectivamente, foram sintetizados pelo m?todo hidrot?rmico. Utilizando-se de fontes como ? alumina hidratada (pseudobohemita), ?cido fosf?rico, s?lica gel, ?gua e diferentes tipos de direcionadores estruturais org?nicos, tais como o: brometo de cetiltrimetilam?nio (CTMABr), di-isopropilamina (DIPA), di-n-propilamina (DNPA) e hidr?xido de tetraetilam?nio (TEOS), nas respectivas amostras. Durante a prepara??o dos silicoaluminofosfatos o processo de cristaliza??o das amostras ocorreu ? temperatura de aproximadamente 200 ?C, durante per?odos que variaram de 18-72 h, quando foi poss?vel obter as fases puras dos SAPOs. Os materiais obtidos foram lavados com ?gua deionizada, secos e calcinados para a remo??o das mol?culas dos direcionadores. Posteriormente, as amostras foram caracterizadas por difra??o de raios-X (DRX), microscopia eletr?nica de varredura (MEV), espectroscopia de absor??o na regi?o do infravermelho (FT-IR), ?rea de superf?cie espec?fica e an?lise t?rmica via TG/DTG. As propriedades ?cidas foram determinadas usando adsor??o de n-butilamina seguida de termodessor??o programada. Esses m?todos revelaram que ?s amostras dos SAPOs apresentaram uma acidez tipicamente fraca a moderada. Entretanto, uma pequena quantidade de s?tios ?cidos fortes foi tamb?m detectada. A desativa??o dos catalisadores foi conduzida pelo coqueamento artificial das amostras, seguidas das rea??es de craqueamento do n-hexano em um microrreator catal?tico de leito fixo com fluxo cont?nuo acoplado em linha com um cromat?grafo a g?s. Como principais produtos foram obtidos: etano, propano, isobutano, n-butano, n-pentano e isopentano. Para determinar a regenera??o do catalisador e a remo??o do coque foi aplicado o m?todo cin?tico Vyazovkin (Model Free Kinetics) / 2020-02-01

Les kësterites, ou Cu2ZnSn(S,Se)4 (CZTS), sont des matériaux semi-conducteurs composés uniquement d'éléments abondants. Leur gap direct compris entre 1.0 et 1.5 eV en fait d'excellents candidats pour remplacer les absorbeurs actuellement utilisés en couches minces. Ce travail de thèse décrit la fabrication de couches minces de Cu2ZnSnS4 par impression de nanoparticules suivie d'un recuit de cristallisation. Différentes synthèses hydrothermales de nanoparticules ont été développées, dont certaines en réacteur à flot continu, en vue d'un développement à plus grande échelle. L'influence des types de précurseurs et des conditions de synthèse sur la composition chimique des particules est étudiée ainsi que leur pureté est évaluée. Le comportement en dispersion colloïdale est ensuite caractérisé et trois fonctionnalisations de surfaces à base de dodecanthiol, dodecyl pyrrolidone et anions sulfures sont présentées. Ces stabilisations permettent la fabrication d'encre jet d'encre et spray adaptées au dépôt sur molybdène. Les couches imprimées et séchées sont recuites sous atmosphère de soufre. Des recuits d'au moins 120 minutes sont nécessaires. Cependant la croissance des couches est hétérogène lorsque celles-ci sont imprimées avec les nanoparticules stabilisées par le dodecanethiol et le dodecyl pyrrolidone. La présence de carbone dans les couches, identifiable par spectroscopie Raman, inhibe la croissance du matériau. Seules les couches minces imprimées à l'aide de nanoparticules purifiées et stabilisées par anions sulfures permettent la croissance homogène du matériau lors du recuit. / Kësterites or Cu2ZnSn(S,Se)4 (CZTS), are semi-conductors only made of abundant elements. Their direct bangap between 1.0 and 1.5 eV makes them excellent candidates for the replacement of the currently used thin film absorbers. This thesis describes the fabrication of thin films of Cu2ZnSnS4 by nanoparticles printing followed by crystallization annealing. Different hydrothermal synthesis of nanoparticles have been developed, some in continuous flow reactor, for a development on a larger scale. The influence of the types of precursors and synthesis conditions on the particals chemical composition purity was evaluated. The behavior of colloidal dispersion is then characterized and three surface functionalization based on dodecanthiol, dodecyl pyrrolidone and sulfide anions are presented. These stabilizations allow the manufacture of inks deposited by inkjet and spray on molybdenum. The printed and dried layers are then annealed in sulfur atmosphere. Annealing of at least 120 minutes are required. However, the growth of the layers is heterogeneous when printed with the nanoparticles stabilized by dodecanethiol and dodecyl pyrrolidone. The presence of high carbon content, prooved by Raman spectroscopy, inhibits the growth of the material. Only thin film printed using purified nanoparticles stabilized by sulfide anions allow homogeneous growth of the material during annealing.

Made available in DSpace on 2016-12-08T17:19:22Z (GMT). No. of bitstreams: 1 Rafaela de Souza Schmidt.pdf: 1614603 bytes, checksum: 4583716d044cc6f09dfcf335690ab75e (MD5) Previous issue date: 2014-01-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The synthesis of zeolites from alternative materials and low cost had great development in recent decades due to the fact of processes using conventional silicon and aluminum solutions are expensive .solutions of silicon and aluminum are extremely expensive. The synthesis can be carried out by any raw material containing predominantly silica and alumina, such as clays and rice husk. Thus, this study aims to develop an alternative methodology for the synthesis of zeolite ZSM-5, using silica extracted from rice husk and commercial metakaolin as raw materials in the composition of the mixture. The process of synthesis solution was hydrothermally sodium in the presence of TPABr and as a structural director. To assess the effect of temperature on the formation of ZSM-5, the synthesis procedure was carried out in temperature ranges between 100 and 170°C. Through the characterization of zeolitic material formed in the crystallization process, it was concluded that the methodology proposed in this work led typical crystalline phases of zeolite ZSM-5, as well as the formation of other zeolite phases. / A síntese de zeólitas a partir de materiais alternativos e de baixo custo teve grande desenvolvimento nas últimas décadas devido ao fato dos processos que utilizam soluções convencionais de silício e alumínio serem caros. A síntese pode ser realizada por qualquer matéria prima que contenha predominância de sílica e alumina, como por exemplo, argilas e casca de arroz. Sendo assim, este trabalho tem como objetivo desenvolver uma metodologia alternativa de síntese de zeólita ZSM-5, empregando sílica extraída da casca de arroz e metacaulim comercial, como matérias primas na composição da mistura reacional. O processo de síntese ocorreu hidrotérmicamente em solução sódica e na presença de TPABr como direcionador estrutural. Para avaliar o efeito da temperatura na formação da ZSM-5, o processo de síntese foi realizado em faixas de temperatura entre 100 e 170°C. Através da caracterização do material zeólítico formado no processo de cristalização, foi concluído que a metodologia proposta neste trabalho conduziu fazes cristalinas típicas de zeólita ZSM-5, bem como a formação de outras fases zeolíticas.

L’objectif de cette thèse est d’élaborer des nanohybrides à base des nanotubes de titanate (TiONts) dans le but de les utiliser comme nanovecteurs d’une molécule thérapeutique : un phénol stilbénique, le 4’ hydroxy 4 (3 aminopropoxy)-trans-stilbène (HAPtS), structurellement proche du trans-resvératrol.Les TiONts sont synthétisés par traitement hydrothermal à partir du dioxyde de titane sous sa forme rutile. Deux méthodes de synthèse hydrothermale (statique et dynamique) ont été étudiées. La deuxième méthode est originale car elle utilise un réacteur conduisant à une agitation mécanique forte par balancement où le temps d’agitation par heure de traitement peut-être contrôlé. Une étude paramétrique a été menée pour évaluer l’impact de la durée de traitement, de la température et du temps d’agitation appliqué par heure sur la morphologie des structures obtenues. Il a été montré que l’agitation par balancement, appliquée durant la synthèse, a un effet accélérateur sur la cinétique de formation des TiONts en mode dynamique. Par optimisation des paramètres de synthèse, il a été possible de réduire la durée de la synthèse des TiONts à 2h seulement, au lieu de 48 h en méthode statique. Des discussions sur la structure cristalline, le mécanisme de formation des TiONts et leur transformation en nanorubans ont également été développées en se basant sur différentes techniques de caractérisations (DRX, MET, ATG, XPS, spectroscopies UV visible, IR et Raman). La morphologie spéciale des TiONts, en spirale (diamètre externe de 10 nm, diamètre interne de 4 nm avec une longueur moyenne d’environ 190 nm) et multicouches (3 à 5 couches) leur confère une surface spécifique élevée (> 200 m²/g).Différentes préfonctionnalisations des TiONts par des ligands organiques biocompatibles ont été effectuées pour améliorer la stabilité des TiONts en suspension et greffer à leur surface des groupements fonctionnels réactifs. Les ligands étudiées sont : deux catéchols, le DHCA et la L-DOPA, l’acide citrique et deux organosilanes, l’APTES et le CPTES. Les paramètres optimaux de greffage ont été déterminés et la présence de liens covalents entre ces ligands et les TiONts ont été établis, principalement par XPS et IR.Après préfonctionnalisation avec le CPTES, le greffage du phénol stilbénique (HAPtS) a été un succès. Cette molécule a été accrochée à la surface des TiONts-CPTES par une réaction de condensation entre le HAPtS et le CPTES par substitution nucléophile et a conduit à un taux de greffage d’environ 20 mg/g de TiONts.Enfin, l’une des originalités de ce travail a consisté à améliorer la biocompatibilité des TiONts, à travers la modification de leur surface par un polymère naturel, le chitosan (CT). Ce dernier a été greffé à la surface des nanotubes par deux méthodes différentes via des liaisons covalentes (greffage étape par étape mettant en œuvre de l’APTES puis du glutaraldehyde) ou via des interactions électrostatiques (adsorption). Après comparaison entre les deux approches, les premiers tests d’évaluation de la toxicité, in vitro (test de cinétique de synthèse des ARN et test du rouge neutre) et in vivo (embryons de poisson zèbre), ont été réalisés et les résultats ont confirmé la biocompatibilité des nanohybrides synthétisés avec les systèmes biologiques. Une étude de la stabilité colloïdale des TiONts-CT dans différents milieux mimant des milieux biologiques a également été menée.Mots clés : Nanotubes de titanate, synthèse hydrothermale dynamique, nanovecteurs, nanohybrides, stabilité colloïdale, fonctionnalisation, greffage, ligands organiques, catéchols, organosilanes, phénol stilbénique, chitosan, biocompatibilité. / The aim of this PhD thesis is to develop new nanohybrids based on titanate nanotubes (TiONts) in order to use them as nanocarrier of a therapeutic molecule: a stilbene phenol, 4'-hydroxy-4-(3-aminopropoxy)-trans-stilbene (HAPtS), which is a transresveratrol derivative.TiONts are synthesized by a hydrothermal treatment from a precursor of rutile titanium dioxide. Two methods of hydrothermal synthesis have been studied (the static and dynamic ones): the second approach uses an original hydrothermal device which provides a vigorous mechanical stirring during the hydrothermal process with controllable stirring time par hour. A parametric study was carried out to evaluate the effect of reaction time, temperature and stirring time during the hydrothermal treatment on the morphology of the obtained products. It has been proved that the mechanical stirring has a great accelerating effect on the kinetics of the TiONts formation during the dynamic hydrothermal synthesis. After optimization of the experimental parameters of the dynamic hydrothermal treatment, it was possible to reduce the time of TiONts synthesis to only 2 hours, instead of 48 hours obtained by the static method. Discussions about the crystal structure of TiONts, about their formation mechanism and their transformation into nanoribbons have been also developed based on different characterization techniques (XRD, TEM, TGA, XPS, UV visible, IR and Raman spectroscopies). Their special hollow morphology (10 nm in outer diameter, inner diameter of 4 nm, average length of about 190 nm) and multilayered structure (3 to 5 layers) impart them a high specific surface area (>200 m²/g). Different prefunctionalizations of TiONts by biocompatible organic ligands have been carried out to improve their colloidal stability and to graft reactive functional groups on their surface. The studied ligands are: two catechols (DHCA and L-DOPA), citric acid and two organosilanes (APTES and CPTES). Optimal grafting parameters were determined and the presence of covalent bonds between these ligands and TiONts was highlighted especially by XPS and IR. After prefunctionalization with CPTES, the stilbenic phenol (HAPtS) was successfully grafted onto TiONts-CPTES surface using a condensation reaction between HAPtS and CPTES through nucleophilic substitution. The resulting grafting rate was of about 20 mg/g of TiONts. Finally, one of the originalities of this work was the improvement of TiONts biocompatibility by surface modification with a natural polymer, chitosan (CT). The latter was grafted by two different approaches via covalent bonds (step by step grafting using APTES then glutaraldehyde as two intermediate molecules) or via electrostatic interactions (adsorption). After comparing the two elaborated nanohybrids, obtained by the two grafting approaches, the first cytotoxicity assessment tests were carried out, in vitro (RNA synthesis test and neutral red test) and in vivo (zebrafish test), and the obtained results confirmed the biocompatibility of these nanohybrids towards biological systems. A colloidal stability study of TiONts-CT in various mimicked biological media was also carried out.Keywords: Titanate nanotubes, dynamic hydrothermal synthesis, nanocarriers, nanohybrids, colloidal stability, functionalization, grafting, organic ligands, catechols, organosilanes, stilbenic phenol, chitosan, biocompatibility.

Made available in DSpace on 2014-10-09T12:41:55Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:16Z (GMT). No. of bitstreams: 0 / As cinzas leves e pesadas de carvão foram utilizadas na síntese das zeólitas (ZCL e ZCP) por tratamento hidrotérmico alcalino. As zeólitas modificadas de cinzas leves e pesadas (ZMSL e ZMSP) foram preparadas pela mistura de ZCL e ZCP com o surfactante brometo de hexadeciltrimetilamônio. Os adsorventes foram caracterizados por diferentes técnicas, tais como: métodos físico-químicos, fluorescência de raios-X, espectroscopia na região do infravermelho, difração de raios-X e microscopia eletrônica de varredura. O processo de adsorção dos corantes cristal violeta (CV) e do ácido laranja 8 (AL8) foi realizado em sistema de batelada com o objetivo de investigar o equilíbrio e a dinâmica dos materiais zeolíticos no tratamento de efluentes. Os modelos de cinética de pseudo-primeira-ordem e pseudo-segunda-ordem foram aplicados aos dados experimentais e a cinética de pseudo-segunda-ordem descreveu a adsorção dos corantes sobre os adsorventes. Estudos da difusão intrapartícula revelaram que as velocidades de adsorção não eram controladas somente pela etapa de difusão. O modelo de Freundlich ajustou-se melhor aos dados experimentais para todos os sistemas estudados, com exceção do sistema CV/ZCL, que seguiu o modelo de Langmuir. As capacidades máximas de adsorção das zeólitas modificadas foram maiores do que aquelas obtidas para as zeólitas não modificadas. Este melhor desempenho é devido ao ambiente hidrofóbico proporcionado pela adsorção do surfactante catiônico na superfície do adsorvente. Os parâmetros das isotermas de adsorção foram usados para prever o design do equipamento para a realização de processo de adsorção descontínuo de estágio simples. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-11-03T16:23:01Z No. of bitstreams: 2 Dissertação - Sandra de Cássia Pereira - 2014.pdf: 3364346 bytes, checksum: 10b7ec2e9cae1b670c3709119ce8f966 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2014-11-03T16:23:40Z (GMT) No. of bitstreams: 2 Dissertação - Sandra de Cássia Pereira - 2014.pdf: 3364346 bytes, checksum: 10b7ec2e9cae1b670c3709119ce8f966 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-11-03T16:23:40Z (GMT). No. of bitstreams: 2 Dissertação - Sandra de Cássia Pereira - 2014.pdf: 3364346 bytes, checksum: 10b7ec2e9cae1b670c3709119ce8f966 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-01-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In recent years, the perovskite type oxides doped with rare-earth ions has attracted great interest in the research, especially in the field of photoluminescence (PL). This property has always attracted the interest of the scientific community, especially since their discovery room temperature. The present work aims to study the PL property CaTiO3 (CT) doped with rare-earth ions Yb (III) and Tm (III). Samples of CT pure and doped with rare-earth ions, Ca1-(x+y)YbxTmyTiO3 (x and y = 0, 0,01, 0,0075, 0,005, ou 0,0025 ), were obtained by co-precipitation method and processing using hydrothermal system assisted by microwave , which was used to be a relatively new, promising little used method of processing. The samples were characterized by different techniques, the X-ray diffraction confirmed to obtain a single phase material of orthorhombic perovskite type structure, confirming that the hydrothermal synthesis method is effective in the samples of interest in shorter periods of time. Ultraviolet-visible absorption spectroscopy, allowed calculation of the "gap" optic, confirming the presence of intermediate levels between the valence band and the conduction in the doped samples. The characterization by SEM and EDX confirmed, respectively, obtaining approximately cubic particles and exclusive presence of the cations of interest. PL results show that the doping of CT formation leads of defects to high and low energy in the samples. The highest FL intensity occurs when the doping is performed in proportion to the doping. / Nos últimos anos, óxidos do tipo perovsquita dopados com íons terras-raras tem atraído grande interesse na pesquisa, principalmente no campo da fotoluminescência (FL). Essa propriedade sempre atraiu o interesse da comunidade científica, principalmente a partir de sua descoberta a temperatura ambiente. O presente trabalho tem como objetivo estudar a propriedade FL do CaTiO3 (CT) dopado com os íons terras-raras Yb(III) e Tm (III). Amostras do CT puro e dopadas com os íons terras-raras, Ca1-(x+y)YbxTmyTiO3 (x e y =0, 0,01, 0,0075, 0,005, ou 0,0025), foram obtidas pelo método de coprecipitação e processadas utilizando o sistema hidrotérmico assistido por micro-ondas, que foi utilizado por ser um método de processamento relativamente novo, bastante promissor e ainda pouco utilizado. As amostras obtidas foram caracterizadas por diferentes técnicas, a difração de raios X confirmou a obtenção de materiais monofásicos com estrutura perovsquita do tipo ortorrômbica, comprovando que o método hidrotérmico é eficiente na síntese das amostras de interesse em curtos períodos de tempo. A espectroscopia de absorção UV-Visível permitiu o cálculo do “gap” óptico, comprovando a presença de níveis intermediários entre a banda de valência e a de condução nas amostras dopadas. A caracterização por MEV e por EDS comprovou, respectivamente, a obtenção de partículas aproximadamente cubicas e a presença exclusiva dos cátions de interesse. Os resultados de FL mostram que a dopagem do CT leva a formação de defeitos de alta e baixa energia nas amostras. E a maior intensidade FL ocorre quando a dopagem é realizada na mesma proporção dos dopantes.

>Magister Scientiae - MSc / Millions of tonnes of fly ash are generated worldwide every year to satisfy the large demand for energy. Management of this fly ash has been a concern and various approaches for its beneficial use have been investigated. Over the last two decades, there has been intensive research internationally that has focused on the use of different sources of fly ash for zeolite synthesis.However, most of the studies have concentrated on class C fly ash and very few have reported the use of South African class F fly ash as feedstock for zeolite synthesis.Class F fly ash from South Africa has been confirmed to be a good substrate for zeolite synthesis due to its compositional dominance of aluminosilicate and silicate phases. However, because differences in quartz-mullite/glass proportions of fly ash from different sources produces impure phases or different zeolite mineral phases under the same activation conditions, the present study focused on optimization of synthesis conditions to obtain pure phase zeolite Na-P1 from class F South African coal fly ash. Synthesis variables evaluated in this study were; hydrothermal treatment time (12 - 48 hours), temperature (100 – 160 oC) and addition of varying molar quantities of water during the hydrothermal treatment step (H2O:SiO2 molar ratio ranged between 0 - 0.49).Once the most suitable conditions for the synthesis of pure phase zeolite Na-P1 from fly ash were identified, a statistical approach was adopted to refine the experiments, that was designed to evaluate the interactive effects of some of the most important synthesis variables. In this case, the four synthesis variables; NaOH concentration (NaOH: SiO2 molar ratio ranged between 0.35– 0.71), ageing temperature (35 oC – 55 oC), hydrothermal treatment time (36 - 60 hours) and temperature (130 oC – 150 oC) were studied. The response was determined by evaluating the improvement in the cation exchange capacity of the product zeolite.The starting materials (fly ashes from Arnot, Hendrina and Duvha power stations) and the synthesized zeolite product were characterized chemically, mineralogically and morphologically by X-Ray fluorescence spectrometry, X-ray powder diffraction, scanning electron microscopy, and transmission electron microscopy. Other characterization technique used in the study were Fourier transform infrared spectroscopy to provide structural information and also monitor evolution of crystallinity during synthesis, as well as cation exchange capacity to determine the amount of exchangeable positively charged ions. Nitrogen adsorption was used to determine the surface area and porosity, and inductively coupled mass spectrometry for multi-elemental analysis of the post-synthesis supernatants.The results from the X-ray diffraction spectroscopy showed that the most pure zeolite Na-P1 phase was achieved when the molar regime was 1 SiO2 : 0.36 Al2O3 : 0.59 NaOH : 0.49 H2O and at synthesis conditions such that ageing was done at 47 oC for 48 hours while the hydrothermal treatment time and temperature was held at 48 hours and 140 oC, respectively. Results from statistically designed experiments show that there was a distinct variation of phase purity with synthesis conditions. From the analysis of linear and non linear interactions, it was found that the main effects were ageing temperature and hydrothermal treatment time and temperature, which also showed some interactions. This experimental approach enabled a clearer understanding of the relationship between the synthesis conditions and the purity of the zeolite Na-P1 obtained.The quality of zeolites is a major determinant in the efficiency of toxic element removal from waste water. Preliminary experiments conducted using optimised zeolite Na-P1 obtained in this study with a cation exchange capacity of 4.11 meq/g showed a high percentage removal of Pb,Cd, Ni, Mn, V, As, B, Fe, Se, Mo Sr, Ba and Zn from process brine obtained from Emalahleni water reclamation plant.In summary, a pure phase of zeolite Na-P1 was obtained from South African class F fly ash feedstock at relatively mild temperature. The systematic approach, incorporating statistical design of experiments, developed in this study resulted in a better understanding regarding the relationships of synthesis parameters in the formation of zeolites from fly ash. The zeolite Na-P1 synthesized with a high cation exchange capacity was effective for removal of toxic elements from brine.

Des cristaux de Ga1-xFexPO4 ont été obtenus par voie hydrothermale avec xmax=0.23. La synthèse hydrothermale in-situ par spectroscopie d'absorption des rayons X a permis de mettre en évidence le rôle essentiel des cations Ga3+ lors de la nucléation et la cristallisation de la phase mixte Ga1-xFexPO4 de structure quartz-α. La solution solide a été particulièrement étudiée par spectroscopie Raman et des calculs théoriques par DFT ont permis d'identifier clairement les modes de vibration dont la fréquence dépend de la composition chimique du matériau (modes couplés). Dans la même famille des matériaux de type MIIIXVO4, la cristallogénèse de monocristaux de GaAsO4 de grande taille (plusieurs cm3) a été réalisée par croissance hydrothermale basse pression (P < 2MPa). A partir de ces cristaux des mesures piézoélectriques sur résonateur ont permis de confirmer que GaAsO4, possède le coefficient de couplage électromécanique le plus élevé de la famille (20%) ce qui représente 2.5 fois les propriétés du quartz. Par ailleurs GaAsO4 possède des propriétés intéressantes dans le domaine de l'optique non-linéaire. Les mesures ont permis d'obtenir un coefficient de couplage électro-optique d11= 2.98pm/V (3.29pm/V par calcul DFT) ce qui place GaAsO4 parmi les matériaux les plus performants dans ce domaine. Compte tenu de sa haute stabilité thermique, GaAsO4 constitue un matériau bi-fonctionnel très prometteur pour des applications high-tech. / Ga1-xFexPO4 single crystals were grown by hydrothermal methods. In-situ absorption X-ray spectroscopy was used to show the essential role of solvated Ga3+ ions during the nucleation and the crystallization of the alpha-quartz type structure. Solid solutions have been investigated by Raman spectroscopy coupled with theoretical DFT calculations. The dependence of vibrational mode frequencies on the chemical composition was studied thereby allowing a linear dependence of PO4 modes frequencies with the iron content (xFe) to be identified. In the second part, crystal growth of large single crystals (several cm3) of GaAsO4 was performed. The piezoelectric coupling coefficient of 20% was measured, which is 2.5 times that of alpha-quartz. Non-linear optical properties were also measured: the electro-optical coupling coefficient d11 is 2.98pm/V (3.29pm/V with DFT calculations). Due to the high thermal stability, GaAsO4 is a very promising bifunctional material for high technology applications.

L’étude de phénomènes thermiques à l’échelle microscopique peut s’avérer compliquée à mettre en place, principalement à cause de l’absence de technique de mesure de température fiable. Dans ce contexte, une technique de mesure de température appelée TIQSI a été développée au sein de l’Institut Fresnel. Dans l’objectif d’étudier des phénomènes thermo-induit à l’échelle microscopique, j’ai monté un microscope capable de contrôler et de quantifier une élévation de température à l'aide de TIQSI et de nanoparticules d’or. Différents phénomènes ont ainsi pu être étudiés.La synthèse hydrothermale regroupe les réactions chimiques utilisant de l’eau liquide à des températures plus élevées que la température d’ébullition. L’utilisation de nanoparticules permet d’avoir de l’eau liquide à des températures supérieures à 100°C (état métastable). J’ai pu ainsi effectuer des réactions de synthèse hydrothermale sans autoclave ce qui constitue un nouveau concept en chimie de synthèse.Une cellule vivante peut-être endommagée par un stress de chaleur ce qui peut détériorer ses protéines. En réponse à ce stress, la synthèse de HSP permet la réparation des protéines endommagées. J’ai pu étudier la dynamique de réponse des HSP ce qui a permis d’illustrer l’intérêt d’une chauffe locale et de TIQSI pour ce genre d’expérience.Une autre application mêlant le surchauffage de l’eau liquide et la biologie a été abordée. Les organismes hyperthermophiles vivent à de très hautes températures (80-110◦C). J’ai pu durant mes expériences observer le déplacement d’hyperthermophiles. Cette avancée constitue les prémices d’expériences plus ambitieuses comme l’étude de l’interaction entre hyperthermophiles. / Nowadays, thermal experiments at the microscopic scale remain challenging to conduct due to the lack of reliable temperature measurment techniques. To solve these problems, a label-free temperature measurement technique called TIQSI has been developed in the Institut Fresnel.With the objective to study new thermal-induced effects on the microscale using TIQSI, I built a microscope aimed to control heat diffusion on the microscale using nanoparticle. Thus, I could study different phenomena in chemistry and biology.Hydrothermal methods in chemical synthesis rely on the use of superheated liquid water as a solvent. It has been shown that gold nanoparticles can be used superheated water in a metastable state. I managed to conduct hydrothermal chemistry experiments using thermoplasmonics without autoclave which represents a new paradigm in chemistry.A living cell can be damaged by a heat stress which can misfold its proteins. To response to this stress, the HSP synthesis enables the reparation of misfolded proteins. I could study the heat stress response of HSP at short time scale which allowed me to illustrate the interest of using TIQSI and a local heat.As an application mixing superheating water and biology, I studied organisms that are able to live at high temperature (80-110°C) namely hyperthermophiles. Motion of these organisms has been studied without autoclave which paves the way to more sophisticated experiments such as the interaction between hyperthermophiles.