Le rejet de métaux lourds dans l'environnement pose des problèmes majeurs pour les écosystèmes et la santé humaine. Parmi les solutions proposées, les techniques d'adsorption semblent particulièrement prometteuses. Ce travail de thèse visait à préparer de nouveaux matériaux à base d'hydroxyapatite afin d'améliorer les propriétés d'immobilisation de métaux lourds (Cr, Pb, Zn). Deux approches ont été explorées. La première repose sur la formation d'hydroxyapatite modifiée par les acides carboxyliques qui présentent une affinité pour le calcium de la phase minérale et pour les ions métalliques. Cette approche permet d'obtenir des matériaux hydrides organo-minéraux poreux. Sur la base des caractérisations effectuées, en particulier par DRX, RMN à l'état solide, porosimétrie d'azote et microscopie électronique, l'effet de l'incorporation des acides carboxyliques dans la structure et la chimie de surface des matériaux obtenus a été discuté. Cette discussion constitue la base de l'étude des propriétés d'adsorption des ions Pb2+ et Zn2+. La deuxième approche repose sur l'élaboration de nanocomposites associant l'hydroxyapatite et la zircone. Ce travail décrit une nouvelle voie de synthèse sol-gel de ces matériaux, conduisant l'association des deux phases permet au matériau composite de présenter une bonne affinité pour le Cr(III) et le Cr(VI).

De nouveaux matériaux aluminosilicates (de Si/Al = 6 à pure silice) à structures hiérarchiques ont été synthétisés sous forme de billes submicrométriques par chimie sol-gel couplée à un procédé de synthèse pas voie aérosol. Les synthèses ont été effectuées à partir de précurseurs inorganiques alcoxydes en présence du copolymère amphiphile [EO]106-[PO]70-[EO]106 et à pH fortement basique fixé par la concentration en hydroxyde de tétrapropylammonium. La porosité des matériaux calcinés, examinée par MET, DRX aux bas angles et volumétrie à l'azote, est caractéristique de matériaux soit mésostructurés, mésoporeux ou macroporeux avec, dans certains cas, une microporosité importante. L'étude de l'influence des paramètres chimiques sur la porosité finale a permis de rationaliser les conditions d'obtention de chaque type de structure et de proposer un mécanisme de formation. Le réseau inorganique des matériaux a été étudié par DRX aux grands angles, IRTF avec ou sans adsorption de lutidine, RMN de l'27Al et de l'1H. Bien que complètement amorphes, ces matériaux se révèlent pourtant beaucoup plus actifs en catalyse de l'isomérisation du m-xylène que les aluminosilicates amorphes de référence.

With increasing attention paid to metal-supported SOFCs recently, metal supports have become important factors in the performance of the cells. The formation of surface oxides and the poisoning of Cr from Cr2O3-forming metal supports often result in the degradation of the cells. However, few studies have focused on developing oxidation resistance and decreasing Cr migration from porous alloys in intermediate temperature metal-supported SOFCs. In this work, Y2O3 and CeO2 coatings were applied to porous AISI 430 stainless steels by sol-gel dip coating. Phases and microstructures of the coatings on the porous metal supports were characterized by XRD and SEM with EDS, respectively. The effects of the coatings on oxidation resistance of the supports were evaluated by cyclic oxidation testing. Electrical and electrochemical properties of LSCF-SDC cathodes and symmetrical cells deposited on the Y2O3-protected metal supports were also investigated. The issue of Cr depletion of the supports was also discussed.

With increasing attention paid to metal-supported SOFCs recently, metal supports have become important factors in the performance of the cells. The formation of surface oxides and the poisoning of Cr from Cr2O3-forming metal supports often result in the degradation of the cells. However, few studies have focused on developing oxidation resistance and decreasing Cr migration from porous alloys in intermediate temperature metal-supported SOFCs. In this work, Y2O3 and CeO2 coatings were applied to porous AISI 430 stainless steels by sol-gel dip coating. Phases and microstructures of the coatings on the porous metal supports were characterized by XRD and SEM with EDS, respectively. The effects of the coatings on oxidation resistance of the supports were evaluated by cyclic oxidation testing. Electrical and electrochemical properties of LSCF-SDC cathodes and symmetrical cells deposited on the Y2O3-protected metal supports were also investigated. The issue of Cr depletion of the supports was also discussed.

Chemical-looping combustion is an indirect oxygen combustion strategy, considered to be the most cost-effective power generation technology with the CO2 inherently concentrated. In this process, a solid oxygen carrier is used to transfer oxygen from the air reactor to the fuel reactor, which completely isolates nitrogen in air to meet with fuels. The oxygen carriers in the combustion process are subjected to the severe environments, such as high temperatures, multi-cycle operations, and thermodynamic limitations. Thus, the preparation of an oxygen carrier with high durability and better kinetics under harsh environment could be an essential part of Chemical-looping combustion development. In this study, modified wet impregnation and co-precipitation methods have been developed. The active ingredient is copper(II) oxide, and the supporting material is either directly from titanium(IV) oxide (anatase 99%) or that prepared from other titanium resources such as titanium tetrachloride and tetrabutyl titanate. Preliminary results showed the prepared oxygen carriers functioned properly in the multi-cycles of oxidization and reduction in TGA at different temperatures. Characterization of used oxygen carriers was carried out using techniques of XRD, and SEM-EDS, which provide information for the difference between oxygen carriers from different preparation methods. Through the comparison, the oxygen carrier from the sol-gel preparation method has better dispersion and oxidation activity than those from mechanical mixing, wet-impregnation, and cox precipitation method. Moreover, towards the oxygen carrier from sol-gel method, nucleation model and diffusion models were determined at different reaction periods.

Cette thèse s'est inscrite dans le cadre du projet ACACIA (Amélioration du CAptage du CO2 Industriel et Anthropique) soutenue par le pôle de compétitivité AXELERA et financé par " FUI " et " LE GRAND LYON ". Notre objectif était d'immobiliser l'anhydrase carbonique dans des gels inorganiques, en particulier la silice afin de préserver la structure de l'enzyme, sa fonctionnalité et de la protéger de l'environnement physico-chimique environnant. Pour cela, des essais préliminaires simples nous ont permis d'élaborer et de construire une cellule, comprenant membrane polymérique poreuse imprégnée de solution enzymatique aqueuse, ou de gel de silice lui-même imprégné de solution aqueuse d'enzyme. A partir de ce montage, nous avons étudié des paramètres importants de la membrane, comprenant un tampon, sa nature, molarité et son pH, ainsi que la taille des pores de la membrane et la concentration en enzyme. Il a été trouvé qu'un tampon à base de bicarbonate permet de déplacer l'équilibre de déprotonation du CO2(aq) vers un pH plus élevé, par l'apport des ions HCO3- équilibrés par des cations comme Na+, et favorise une contribution plus importante à la diffusion du CO2 à travers la membrane. Nous avons également observé que quelque soit le gaz de captage (100 % et / ou 10 % de CO2), le tampon et le type de membrane, une perméance maximum a été observée pour une concentration en enzyme de 0.2 mg mL-1.

Although enzymes show great potential for use in industrial applications, their implementation from a practical perspective is still somewhat limited by various shortcomings in the area of enzyme immobilization. The use of silica sol-gels for protein entrapment has been studied extensively over the past 15 years or so. However, our understanding of the interactions between the immobilization matrix and the entrapped biomolecules is still relatively poor. Non-invasive in situ spectroscopic characterization is a promising approach to gain a better understanding of the fundamentals governing sol-gel immobilization. This thesis describes the application of Fourier transform infrared (FTIR) microscopy, two dimensional (2D) FTIR and fluorescence spectroscopy to characterize the immobilization matrix, entrapped model proteins and their interactions. Hydroperoxide lyase (HPL [E.C. 4.1.2.]) was chosen as a potential model protein for sol-gel entrapment. HPL activity was evaluated by use of factorial experimental design investigating the effects of KCl and Triton X-100 on HPL activity with 13-hydroperoxy-octadecadienoic acid (LA-OOH) and the novel water soluble 13-hydroperoxy-octadienoyl sulfate (LS-OOH) as substrates. The highest HPL activity was achieved under aqueous conditions with high salt and low surfactant concentrations and LA-OOH as the substrate. A significant interaction between salt and surfactant as well as salt and substrate was identified and a hypothesis to explain the basis of the interaction phenomena is presented. To analyze sol-gels with spectroscopic techniques, a sample format amenable to these techniques was needed. Therefore, a spin-coating technique for the preparation of aluminum or glass supported sol-gel thin films containing immobilized protein and a varying degree of the organically modified precursor propyltrimethoxysilane (PTMS) was developed. This approach produced samples that were suitable for chemical mapping using FTIR microscopy or fluorescence spectroscopic investigations. A data analysis method was developed to extract information on chemical speciation and distribution from FTIR data matrices obtained through FTIR microscopy. Results indicate that sol-gel thin films are not homogeneous on the microscopic level. Instead, they are heterogeneous with a clustering in the distribution of the model proteins studied (lysozyme [E.C. 3.2.1.17], lipase [E.C. 3.1.1.3] and bovine serum albumin (BSA)) at the scale investigated. The appearance of these clusters was found to depend on the type of protein entrapped, as well in some cases on the composition of the sol-gel. Moreover, the PTMS distribution was positively correlated with the protein distribution in the case of lipase and negatively correlated in the case of lysozyme and BSA. Additionally, sol-gels with a higher PTMS content appeared to conserve protein structure in areas where lipase clustered. Lysozyme and BSA, on the other hand, seemed to retain their structures in high concentration clusters better at lower PTMS content. A hypothesis taking into account the surface hydrophobicity of the proteins and the sol-gel composition as the basis for these phenomena is proposed. Fluorescence spectroscopy revealed that the PTMS content of the sol-gels had a direct effect on the physical properties of the immobilized proteins as evidenced by a blue shift of the intrinsic tryptophan (TRP) fluorescence. Temperature-dependent fluorescence spectroscopy revealed that the amount of TRP quenching was inversely proportional to the PTMS content of the sol-gel, suggesting that there were varying amounts of water available for quenching for the different immobilized enzyme systems. Analysis of the sol-gels by 2D FTIR spectroscopy with a focus on the amide A region using Gaussian peak deconvolution revealed two different species of water for the 50 % PTMS thin film sol-gels with BSA that could be described as fully and not fully H-bonded. It was also found that these species of water showed different removal profiles during thermal treatment. 2D FTIR of the amide I region followed by absorbance difference spectrum evaluation revealed that the temperature stability of the three model proteins was also sol-gel composition dependent. A hypothesis that the surface characteristics of the proteins determine the nature of the composition dependence is presented.

Although enzymes show great potential for use in industrial applications, their implementation from a practical perspective is still somewhat limited by various shortcomings in the area of enzyme immobilization. The use of silica sol-gels for protein entrapment has been studied extensively over the past 15 years or so. However, our understanding of the interactions between the immobilization matrix and the entrapped biomolecules is still relatively poor. Non-invasive in situ spectroscopic characterization is a promising approach to gain a better understanding of the fundamentals governing sol-gel immobilization. This thesis describes the application of Fourier transform infrared (FTIR) microscopy, two dimensional (2D) FTIR and fluorescence spectroscopy to characterize the immobilization matrix, entrapped model proteins and their interactions. Hydroperoxide lyase (HPL [E.C. 4.1.2.]) was chosen as a potential model protein for sol-gel entrapment. HPL activity was evaluated by use of factorial experimental design investigating the effects of KCl and Triton X-100 on HPL activity with 13-hydroperoxy-octadecadienoic acid (LA-OOH) and the novel water soluble 13-hydroperoxy-octadienoyl sulfate (LS-OOH) as substrates. The highest HPL activity was achieved under aqueous conditions with high salt and low surfactant concentrations and LA-OOH as the substrate. A significant interaction between salt and surfactant as well as salt and substrate was identified and a hypothesis to explain the basis of the interaction phenomena is presented. To analyze sol-gels with spectroscopic techniques, a sample format amenable to these techniques was needed. Therefore, a spin-coating technique for the preparation of aluminum or glass supported sol-gel thin films containing immobilized protein and a varying degree of the organically modified precursor propyltrimethoxysilane (PTMS) was developed. This approach produced samples that were suitable for chemical mapping using FTIR microscopy or fluorescence spectroscopic investigations. A data analysis method was developed to extract information on chemical speciation and distribution from FTIR data matrices obtained through FTIR microscopy. Results indicate that sol-gel thin films are not homogeneous on the microscopic level. Instead, they are heterogeneous with a clustering in the distribution of the model proteins studied (lysozyme [E.C. 3.2.1.17], lipase [E.C. 3.1.1.3] and bovine serum albumin (BSA)) at the scale investigated. The appearance of these clusters was found to depend on the type of protein entrapped, as well in some cases on the composition of the sol-gel. Moreover, the PTMS distribution was positively correlated with the protein distribution in the case of lipase and negatively correlated in the case of lysozyme and BSA. Additionally, sol-gels with a higher PTMS content appeared to conserve protein structure in areas where lipase clustered. Lysozyme and BSA, on the other hand, seemed to retain their structures in high concentration clusters better at lower PTMS content. A hypothesis taking into account the surface hydrophobicity of the proteins and the sol-gel composition as the basis for these phenomena is proposed. Fluorescence spectroscopy revealed that the PTMS content of the sol-gels had a direct effect on the physical properties of the immobilized proteins as evidenced by a blue shift of the intrinsic tryptophan (TRP) fluorescence. Temperature-dependent fluorescence spectroscopy revealed that the amount of TRP quenching was inversely proportional to the PTMS content of the sol-gel, suggesting that there were varying amounts of water available for quenching for the different immobilized enzyme systems. Analysis of the sol-gels by 2D FTIR spectroscopy with a focus on the amide A region using Gaussian peak deconvolution revealed two different species of water for the 50 % PTMS thin film sol-gels with BSA that could be described as fully and not fully H-bonded. It was also found that these species of water showed different removal profiles during thermal treatment. 2D FTIR of the amide I region followed by absorbance difference spectrum evaluation revealed that the temperature stability of the three model proteins was also sol-gel composition dependent. A hypothesis that the surface characteristics of the proteins determine the nature of the composition dependence is presented.

As microprocessors move towards higher frequencies, lower operating voltages and higher power consumption, supplying noise-free power to the ICs becomes increasingly challenging. Decoupling capacitors with low inductance interconnections are critical to meet the power supply impedance targets. A variety of capacitors are used today to provide decoupling at different frequencies. Surface-mount multi-layer ceramic capacitors currently used at package level provide decoupling only till about 100 MHz because of the component and lead inductances. Embedding thin film capacitors into the package can expand the operating range of package level capacitors to low GHz frequencies. Thin films with capacitance of several microfarads and organic-compatible processes are required for embedding decoupling capacitors at package level. The organic-compatible high-permittivity materials available today do not provide adequate capacitance for the application on hand. While ferroelectric thin films can provide the required capacitance, processing temperatures over 300o C are required to achieve crystalline films with high permittivity. Hence, there is a need to develop novel materials and processes to integrate decoupling capacitors into currently prevalent organic packages. To this end, hydrothermal synthesis and sol-gel synthesis of BaTiO3 films were explored in this study. BaTiO3 films were synthesized by low temperature hydrothermal conversion of metallic titanium. Hydrothermal process parameters such as bath molarity and temperature were optimized to obtain thin films with grain sizes close to 100 nm, at temperatures less than 100o C. Novel post-hydrothermal treatments were developed to improve the dielectric properties of the films. Sol-gel process requires sintering at >700o C to obtain crystalline BaTiO3 films. However, the films can be synthesized on free-standing copper foils and subsequently integrated into organic packages using lamination. Prevention of foil oxidation during sintering is critical. Nickel and titanium barriers explored in this study were ineffective due to instabilities at the interfaces. Hence, films were synthesized on bare copper foils by controlling the oxygen partial pressure during sintering. Using these techniques BaTiO3 thin films with capacitances of 400 1000 nF/cm2 and breakdown voltages of 6 15 V were demonstrated. The films synthesized via either techniques exhibited stable dielectric properties up to 8 GHz owing to fine grain sizes.

Abstract This thesis conducts a comprehensive investigation of the of the physical chemistry related to the TEOS-based porous materials prepared by so-gel approach and develops the fast qualification technology for the hydrolysis and condensation reaction of sol-gel process. The porous materials were prepared by introducing a polymer polyethylene glycol (PEG) into sol-gel after different aging times and with different drying and annealing processes. The effects of pH and addition of PEG on sol-gel derived SiO2 powders for purification of ethanol are studied. The methods and results of this work provide valuable reference for the development of other functional materials such as low k dielectric materials. In the first part, the long-term behavior of the hydrolysis and condensation reaction of the tetraethoxysilane (TEOS) pre-solution at different pH values with and without addition of polyethyleneglycol (PEG) for various aging times was characterized by liquid 1H, 13C, and 29Si NMR spectroscopy.The experimental results demonstrate that alcohol was generated in the TEOS pre-solutions with and without addition of PEG at pH 3 and pH 9 after aging, implying the occurrence of hydrolysis and condensation. The rate of hydrolysis and condensation for the TEOS pre-solution at pH 3 was found to follow the trend of the pre-solution with PEG 2000 > pre-solution with PEG 200 > pre-solution without PEG. However, after adding PEG, the oxygen atom of the deprotonated silanol group (siloxy) of the hydrolyzed TEOS pre-solution at pH3 acted as a reaction center. The result indicates that the oxygen atom is more susceptible to electrophilic attack, resulting in an increased reaction rate. Consequently, the rate of hydrolysis and condensation for of the TEOS pre-solution at pH 9 follows a different order: pre-solution with PEG 200 > pre-solution without PEG > presolution with PEG 2000. The slowest reaction rate of the TEOS pre-solution when adding PEG 2000 is related to the tangled chains of PEG 2000 which sterically reduces the hydrolysis and condensation reaction. This work shows that the correlation between the pH and aging time on hydrolysis and condensation reaction of the TEOS pre-solution can be effectively monitored by liquid 1H NMR spectroscopy, supported by 13C and 29Si liquid NMR spectra. The data obtained should assist optimizing the pH, polymer type/size/concentration and the aging time in the preparation of polymer modified TEOS sols In the second part, SiO2 powders were prepared by the sol-gel in combination with oven-drying method before and after annealing.The experimental result demonstrates the rate of hydrolysis and condensation occurs at a fast rate in TEOS with and without adding PEG at pH3 than in any other pH levels. Because free space can lead to the vaporization of H2O, the ionization of ammonia decreases (i.e., reduction the amount of hydroxide ion), which arises from the rate of hydrolysis and condensation decreases when TEOS at pH9. After attaching PEG, the oxygen atom of the deprotonated silanol group (siloxy) for of the hydrolyzed TEOS pre-solution at pH 3 acted as a reaction center. The result indicates the oxygen atom is more susceptible to electrophilic attack, resulting in an increased reaction rate. Thus, a maximum in the powder yield is reached for TEOS pre-solution with and without adding PEG at pH 3. The SiO2 powder with adding PEG of higher molecular weight presents higher adsorption capacities, pertaining to a greater amount of hydrophilic hydroxyl groups of PEG with higher molecular weight. After annealing, the surface area of SiO2 powder prepared from the TEOS pre-solutions increases as compared with powder without adding PEG and enhances the adsorption of water. A potential absorbent SiO2 powders for producing purified ethanol suitable for fuel and industrial use, can be fabricated by using sol-gel route by careful selection of pH and PEG molecular weight. In addition, during the preparation and characterization of these materials, some interesting phenomena were observed, which are academically valuable. For instance, some samples show very narrow 1H MAS spectra and yet has high 1H-29Si CPMAS sensitivety. This phenomenon suggests us that CPMAS sensitivety may be improved by a new route, i.e., by properly preparing the sample so that CP efficiency is enhanced.