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2D struktury na bázi fosfonátů kovů; vztahy mezi uspořádáním a vlastnostmi studované metodami molekulárních simulací / 2D structures based on metal phosphonates; relationships between arrangement and properties studied by molecular simulations methodsŠkoda, Jakub January 2019 (has links)
This work deals with the structural analysis of layered zirconium sulfophenylphosphonates and their intercalates with the use of the classical molecular simulation methods. The inner composition of both fully and partially sulfonated layers was determined in agreement with available experimental data, especially chemical analysis, thermogravimetric measurements and X-ray diffraction. The calculations revealed the positions of the water molecules in the planes of sulfo groups which strongly affect the resultant diffraction pattern. Within the zirconium sulfophenylphosphonate layered structure, the arrangements of intercalated species based on optically active dipyridylamine molecules and cations of sodium, copper and iron were solved with the respect to the agreement with experimental results and values of potential energy. In case of the dipyridylamine molecules and its derivatives, the resultant disordered partially row arrangements of the organic molecules in the interlayer were showed to influence the dipole moment of the intercalate. From this point of view, nitro-derivative has been picked out as the most suitable for potential applications. Regarding the intercalated cations, sodium cations take up the space of water molecules next to the sulfo groups while copper and iron cations are distributed in a...
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Mineral Surface Catalyzed Polymerization Of Estrogen And Microbial Deactivation By Fe3+-Saturated Montmorillonite: A Potentially Low Cost Material For Water DecontaminationQin, Chao 07 February 2017 (has links)
With advantages of high cation exchange capacity, swelling-shrinking property and large specific surface area, monmtorillonite is chosen as a carrier and modified with Fe3+ saturation for estrogen decontamination. 17β-Estradiol (βE2) has highest estrogenic activity among estrogens and is selected as representative compound. Rapid βE2 transformation in the presence of Fe3+ - saturated montmorillonite in aqueous system was observed and βE2 oligomers were the major βE2 transformation products. About 98% of βE2 were transformed into oligomers which are >107 times less water-soluble than βE2 and therefore are much less bioavailable and mobile. Fe3+ -saturated montmorillonite catalysis achieved highest βE2 removal efficiency at neutral solution pH and higher temperature. Common cations did not have impact on the reaction efficiency. Dissolved organic matter slightly reduced βE2 removal efficiency. Regardless of wastewater source, ~40% βE2 removal efficiency was achieved for wastewater effluents when they were exposed to same dosage of Fe3+ -saturated montmorillonite as that for simple water systems which achieved ~83% removal efficiency. For real wastewater that contained higher organic matter, higher dosage of Fe3+ -saturated montmorillonite would be needed to create available reaction sites for βE2. This thesis also reports that Fe3+ -saturated montmorillonite effectively deactivate wastewater microorganisms. Microbial deactivation rate was 92±0.6% when secondary wastewater effluent was mixed with Fe3+ -saturated montmorillonite at 35 mg/mL for 30 min, and further increased to 97±0.6% after 4-h exposure. Freeze-drying Fe3+ -saturated montmorillonite iii after each usage resulted in 82±0.5% microbial deactivation efficiency even after fourth consecutive use. For convenient application, Fe3+ -saturated montmorillonite was further impregnated into filter paper through wet-end addition and formed uniformly impregnated paper. Scanning electron microscopy (SEM) imaging showed Fe3+ -saturated montmorillonite was evenly dispersed over cellulose fiber surface. When filtering 50 mL and 200 mL water spiked with live Escherichia coli (E. coli) cells at 3.67×108 CFU/mL, Fe3+ -saturated montmorillonite impregnated paper with 50% mineral weight loading deactivated E. coli with 99% and 77%, respectively. Dielectrophoresis and impedance analysis of filtrate confirmed that the deactivated E. coli passing through Fe3+ -saturated montmorillonite paper did not have trapping response due to higher membrane permeability and conductivity. The results demonstrate feasibility of using Fe3+ -saturated montmorillonite impregnated paper for convenient point-of-use drinking water disinfection. / Ph. D.
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Réactivité des matériaux argileux dans un contexte de corrosion métallique. Application au stockage profond des déchets radioactifs en site argileuxPerronnet, Murielle 14 October 2004 (has links) (PDF)
Afin d'assurer le confinement de déchets radioactifs en milieu géologique profond, il est envisagé d'utiliser des matériaux argileux de site et des bentonites. Leur stabilité en présence de fer métal, constituant des conteneurs de déchets, est étudiée. Ces études démontrent que la réactivité de tels matériaux est principalement portée par les smectites dioctaédriques et les kaolinites qu'ils contiennent. En revanche, la présence de sulfures inhibe la réaction Fe(0)-argiles. La nature du produit de réaction dépend de la quantité de fer métal disponible. A pH basique, par contact physique avec les agents oxydants de la smectite (H+, OH- et Fe3+), le Fe(0) est corrodé. Cette réaction est favorisée par les hétérogénéités des surfaces latérales de la smectite, qui altérée définit un micro-domaine à l'intérieur duquel nucléent des serpentines-Fe si l'apport en fer est suffisant. De telles néoformations entrainent une diminution des propriétés de confinement de la barrière argileuse.
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