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1
Bachmaf, Samer. "Uranium sorption on clay minerals". Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2010. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-62404.
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The objective of the work described in this thesis was to understand sorption reactions of uranium occurring at the water-clay mineral interfaces in the presence and absence of arsenic and other inorganic ligands. Uranium(VI) removal by clay minerals is influenced by a large number of factors including: type of clay mineral, pH, ionic strength, partial pressure of CO2, load of the sorbent, total amount of U present, and the presence of arsenate and other inorganic ligands such as sulfate, carbonate, and phosphate. Both sulfate and carbonate reduced uranium sorption onto IBECO bentonite due to the competition between SO42- or CO32- ions and the uranyl ion for sorption sites, or the formation of uranyl-sulfate or uranyl-carbonate complexes. Phosphate is a successful ligand to promote U(VI) removal from the aqueous solution through formation of ternary surface complexes with a surface site of bentonite.
In terms of the type of clay mineral used, KGa-1b and KGa-2 kaolinites showed much greater uranium sorption than the other clay minerals (STx-1b, SWy-2, and IBECO montmorillonites) due to more aluminol sites available, which have higher affinity toward uranium than silanol sites. Sorption of uranium on montmorillonites showed a distinct dependency on sodium concentrations because of the effective competition between uranyl and sodium ions, whereas less significant differences in sorption were found for kaolinite. A multisite layer surface complexation model was able to account for U uptake on different clay minerals under a wide range of experimental conditions. The model involved eight surface reactions binding to aluminol and silanol edge sites of montmorillonite and to aluminol and titanol surface sites of kaolinite, respectively. The sorption constants were determined from the experimental data by using the parameter estimation code PEST together with PHREEQC. The PEST- PHREEQC approach indicated an extremely powerful tool compared to FITEQL.
In column experiments, U(VI) was also significantly retarded due to adsorptive interaction with the porous media, requiring hundreds of pore volumes to achieve breakthrough. Concerning the U(VI) desorption, columns packed with STx-1b and SWy-2 exhibited irreversible sorption, whereas columns packed with KGa-1b and KGa-2 demonstrated slow, but complete desorption. Furthermore, most phenomena observed in batch experiments were recognized in the column experiments, too.
The affinity of uranium to clay minerals was higher than that of arsenate. In systems containing uranium and arsenate, the period required to achieve the breakthrough in all columns was significantly longer when the solution was adjusted to pH 6, due to the formation of the uranyl-arsenate complex. In contrast, when pH was adjusted to 3, competitive sorption for U(VI) and As(V) accelerated the breakthrough for both elements.
Finally, experiments without sorbing material conducted for higher concentrations of uranium and arsenic showed no loss of total arsenic and uranium in non-filtered samples. In contrast, significant loss was observed after filtration probably indicating the precipitation of a U/As 1:1 phase.
2
Crawford, R. J. "Interparticle forces in clay minerals". Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291033.
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Humes, R. "Interparticle forces in clay minerals". Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370276.
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Makihara, Hiroshi. "Water film thickness in the clay-water system". Diss., The University of Arizona, 1999. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1999_20_sip1_w.pdf&type=application/pdf.
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Umar, I. M. "Uptake of fission products onto clay minerals". Thesis, University of Salford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376882.
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6
Edge, J. S. "Hydrogen adsorption and dynamics in clay minerals". Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1462102/.
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A new class of hydrogen storage material (HSM), the swelling clay minerals, is introduced by the investigation of laponite, a representative smectite. Simple ion exchange allows for a diverse range of charged species to be studied as possible adsorption sites for H2 within the laponite interlayer, while a sub-monolayer of water pillars the interlayers apart by 2.85 Å, close to the kinetic diameter of H2. Neutron diffraction shows that the 001 peak, representing the clay d-spacing, is directly affected by the introduction of H2 or D2, confirming intercalation into the interlayers. Volumetric adsorption isotherms and neutron scattering show that laponites with 3 wt% H2O rapidly physisorb 0.5-1 wt% H2 at 77 K and 80 bar, with low binding enthalpies (3.40-8.74 kJ mol-1) and consequently low room temperature uptake (0.1 wt% at 100 bar). The higher structural density of clays results in lower H2 densities than MOFs and activated carbons, however some cation-exchanged forms, such as Mg and Cs, show promise for improvement having capacities of 22.8 g H2 per litre at 77K, 80 bar, intermediate between AX-21 and IRMOF-20. At low coverage, INS spectra reveal up to five adsorption sites with low rotational energy barriers (0.7-4.8 kJ mol-1), persisting up to at least 50 K. Analysis of quasielastic neutron scattering (QENS) spectra for Ca-laponite expanded with 3 wt% H2O reveals two populations of interlayer H2: one immobile up to 100 K and localised to the Ca2+ cations, while the other diffuses by jump diffusion at a rate of 1.93 0.23 Å2 ps-1 at 80 K, 60% slower than in the bulk (Dbulk = 4.90 0.84 Å2 ps-1). Arrhenius analysis gives activation energies of 188 28 K for the calcium and 120 32 K for the sodium form, comparable to the range for activated carbons. The adsorbate phase density of H2 in laponite interlayers at 40 K is 67.08 kg m-3, close to the bulk liquid density of 70.6 kg m-3. Jump lengths of 3.2 0.4 Å for Ca-laponite measured by QENS at 40 K are similar to the H2-H2 nearest neighbour distance in condensed H2 (3.79 Å). Thus data from a variety of techniques provides a coherent model for the structure and behaviour of H2 in laponite. The experimental achievement of a two-dimensional film of liquidlike H2 confined within the interlayers up to 40 K is of great interest for the field of superfluidics, since it may be possible to supercool liquid hydrogen confined in laponite interlayers below the predicted Bose-Einstein condensation temperature at 1 K.
7
Chow, John Kam Keung. "Sorption of radionuclides onto clay minerals and soils". Thesis, University of Salford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241543.
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Bray, Helen Jane. "Kinetics of high-temperature transformations of clay minerals". Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249204.
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Michael, Paul J. "Studies of clay minerals and their decomposition products". Thesis, Aston University, 1989. http://publications.aston.ac.uk/9813/.
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Mõssbauer spectroscopy and X-ray diffraction of five coals revealed the presence of pyrite, illite, kaolinite and Quartz, together with other minor phases. Analysis of the coal ashes indicated the formation of hematite and an Fe (3+) paramagnetic phase, the latter resulting from .the dehydroxylation of the clay minerals during ashing at 700 to 750 C. By using a combination of several physicochemical methods, different successive stages of dehydroxylation, structural consolidation, and recrystallisation of illite, montmorillonite and hectorite upon thermal treatment to 1300 C were investigated. Dehydroxylation of the clay minerals occurred between 450 and 750 C, the X-ray crysdallinity of illite and montmorillonite remaining until 800 C. Hectorite gradually recrystallises to enstatite at temperatures above 700°C. At 900 C the crystalline structure of all three clay minerals had totally collapsed. Solid state reactions occurred above 900 C producing such phases as spinel, hematite, enstatite, cristobalite and mullite. Illite and montmorillonite started to melt between 1200 and 1300°C, producing a silicate glass that contained Fe(3+) and Fe(2+) ions. Ortho-pnstatite, clino-enstatite and proto-enstatite were identified in the thermal products of hectorite, their relative proportions varying with temperature. Protoenstatite was stabilised with respect to metastable clinoenstatite upon cooling from 12000 C by the presence of exchanged transition metal cations. Solid state Nuclear Magnetic Resonance spectroscopy of thermally treated transition metal exchanged hectorite indicated the levels at which paramagnetic cations could be loaded on to the clay before spectral resolution is significantly diminished.
10
Sunwar, Chandra Bahadur. "Interaction of some thiazine dyes with clay minerals". Thesis, University of North Bengal, 1985. http://hdl.handle.net/123456789/847.
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Thomas, Susan Murphree. "The synthesis and characterization of novel, inorganically pillared molecular sieves". Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/30891.
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Bishop, Michael Edward. "MICROBIAL REDUCTION OF FE(III) IN MULTIPLE CLAY MINERALS BY SHEWANELLA PUTREFACIENS AND REACTIVITY OF BIOREDUCED CLAY MINERALS TOWARD TC(VII) IMMOBILIZATION". Miami University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=miami1291059786.
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Ugochukwu, Uzochukwu Cornelius. "Biodegradation of crude oil hydrocarbons supported on clay minerals". Thesis, University of Newcastle Upon Tyne, 2011. http://hdl.handle.net/10443/1329.
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Clay minerals are the most abundant minerals near the earth’s surface and play very important roles in biogeochemical processes. They have been found very useful in various industrial applications. The surface properties of clay minerals such as high specific surface area (SSA) and cation exchange capacity (CEC) make them able to act as catalysts, supports and sorbents of toxic and radioactive chemicals. However, their role during the biodegradation of crude oil hydrocarbons is not well understood. The main aim of this research project was to investigate the capabilities of the various forms and types of clay minerals in supporting the microbial degradation of crude oil hydrocarbons so as to gain better understanding of their potential role in the bioremediation of oil polluted sites. The role of clays in hydrocarbon removal was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. The clays used for this study were bentonite, palygorskite, saponite and kaolinite. Clays were treated to produce acid activated clays and organoclays; homoionic interlayer bentonites were also used in this study. The study identified volatilization and adsorption as processes that will take place alongside biodegradation and therefore needed to be accounted for in the assessment of the effects of the clays. The study indicated that acid activated clays, organoclays, untreated kaolinite, K-bentonite, Zn-bentonite and Cr-bentonite were inhibitory to biodegradation of the hydrocarbons, via different mechanisms, whereas Ca-bentonite and Fe-bentonite were stimulatory to biodegradation with about 80% removal of the total petroleum hydrocarbons (TPH) due to biodegradation. The ‘local bridging effect’ and polarization of the interlayer water were identified as two opposing influences arising from the interlayer cations of clay minerals that probably determine the extent of biodegradation of the hydrocarbons. Adsorption of hydrocarbons was significant during biodegradation especially with unmodified palygorskite, Zn-bentonite and K-bentonite as each of them caused more than 40% removal of TPH by adsorption in the experimental microcosm containing 5:1 ratio (w/w) of clay to oil. The process of adsorption of aromatic compounds in the crude oil was believed to take place via cation-π interactions. The correlation between extent of biodegradation and surface area is more robust than that between extent of biodegradation and CEC. The same trend applies with adsorption indicating that both biodegradation and adsorption are more surface area dependent than CEC.
14
Zhang, Li. "Clay Minerals Supporting Microbial Metabolic Activities in Natural Sediments". Miami University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami1564142598119446.
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15
Fuller, Adam James. "Caesium and strontium sorption to sediment and clay minerals". Thesis, University of Leeds, 2014. http://etheses.whiterose.ac.uk/7481/.
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Radioactive caesium (137Cs) and strontium (90Sr) are two of the most important contaminant radionuclides present in many terrestrial environments, as a result of accidental and approved releases from anthropogenic nuclear activity. This thesis investigates the sorption of Cs and Sr onto the surfaces of common terrestrial minerals and a mixed phase sediment. The key findings of the work were with regard to the effect of solution pH and ionic strength on changing the mechanism of Cs and Sr interaction with reactive mineral surfaces. Caesium was found to sorb to multiple sorption sites within the mixed phase sediment. The first of these was a Cs selective site at the edge of the illite interlayer, known as the frayed edge site. It was determined from electron microscopy and x-ray absorption spectroscopy that Cs was selectively incorporated and retained in the interlayer structure in inner-sphere complexes. Cs was also found to sorb to two other main sorption sites in competition with other cations. Therefore the concentrations of Cs sorbing to the mineral surfaces were greatly reduced in low pH or high ionic strength conditions. Solution pH and ionic strength also played a major role in Sr sorption. At intermediate pH Sr sorbed to the surface of illite, chlorite and goethite in outer-sphere complexes. Therefore the presence of competing ions in solution significantly reduced total Sr sorption. However, at very high pH, Sr was specifically adsorbed into inner-sphere surface complexes. This allowed significant concentrations of Sr to sorb to the mineral surface even in high ionic strength solutions. The findings of this thesis mark a significant advance in understanding the fundamental processes governing the behaviour of 137Cs and 90Sr in the environment. Particularly it shows the importance of groundwater chemistry in governing sorption behaviour.
16
Soto, Chris. "Do Clay Minerals affect the thickener operationin Chuquicamata mine, Calama, Chile?" Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-77458.
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Chuquicamata mine mineralogy has been studied performing both X-Ray Diffraction (XRD) and X-RayFluorescence (XRF) to determine whether there is any influence in the thickener operations. Thetargeted minerals were the clay group because of their detrimental effect on mining operations asmodify the rheology of the suspensions. The operation stages most affected by the presence of the clayminerals are gravity separation, milling, conveyor belts, flotation and specially thickener operations. Inorder to cope with Chuquicamata production, the plant is constantly fed from a neighboring ore calledRadomiro Tomic (RT) ore, a secondary sulfide enrichment. At Chuquicamata, the thickener operatorfeedback has been pointed out that every time the concentrator plant is fed in high ratio with this so-called RT ore the mineral processing is hindered. For this reason, RT ore samples from a criticaloperation day were sent to Sweden for mineralogical analysis. In addition, flotation tailings from thethree Chuquicamata concentrator plants were also sent aimed to perform thickener pilot tests. In thismanner, it was seen if it could be possible to achieve new operational strategies in Chuquicamatathickener operations given the current Chuquicamata mineralogy and physical conditions in the flotationtailings.From the XRD analysis, the following clay minerals were identified in order of abundance: Illite>>Kaolinite>SmectiteThus, illite reached up to 23.3vol% being the highest clay amount, followed by lower case kaolinite up to2.5% and up to 1% of smectite values correspond for the RT sample. However, the clay content in theflotation tailings samples were less than expected. Also, clay Crystallinity was also assessed for its abilityto interfere negatively with the pulp rheology, and the results showed that there is a strong link amongpoor crystallized smectite clay with the semi-autogenous mill compare to those samples where themilling was performed in the traditional steel media. Along with the three clay minerals found, quartz,potassic feldspar, and plagioclase were also identified, accounting for up to 76% of the representativesample. The silicate minerals are thought to be problematic in Chuquicamata thickener operations givenits high amount, especially in <2 µm size.For the thickener tests, three types of polyacrylamide were used plus the current Chuquicamataflocculant. Prior to the sedimentation batch test, the rheology of the flocculants was measured in arange of 0.02%w/w to 1%. It was found that flocculant concentrations between 0.02 to 0.05%w/w themost suitable in terms of avoiding suspension rheology increase. After establishing suitable flocculantconcentrations solutions, these were used in the thickener pilot tests at conditions similar to thoseperformed in Chuquicamata thickener operations. Two criteria were used to analyze the bestsedimentation conditions: Initial settling rate (ISR); and Turbidimeter. At pH in a range of 11-12 and 15%solid, bridging flocculation probed to be the most suitable conditions for Chuquicamata thickeneroperations. Moreover, a polyacrylamide blend was tested aiming to achieve high sedimentationperformances. The flocculant blend reached both the highest initial sedimentations rate up to 48m/hand turbidity values below 20NTU at addition rate 5g/t and 7g/t. On the other hand, Chuquicamatacurrent flocculant only reached the highest values of 36m/h and turbidity of 40NTU at an addition rateof 5g/t. In this way, the current work established that conditions at Chuquicamata thickener operation 4can be improved by understanding the absorption process among particle-polymer and mineralogy ofthe mine.Hence, the implication of this work to Chuquicamata mine is a better knowledge of its mineralogyespecially concerned with it is believed that clay minerals are not the only mineralogical factors thatcould be hindering thickener operations in Chuquicamata. Other factors that also could be problematicare: high content of silicates; clay crystallinity, particle size and mixed clay. In addition, the improvementin the thickener sedimentation operations will bring better use of the water by increasing therecirculation towards the concentrator area in a friendly way with the environment and communitiesthat also demand water in the arid region of the Atacama Desert.
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McCann, Graham Francis. "The study of layered materials and their intercalated compounds". Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358320.
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Hinds, Ian Charles. "Characterisation of colloids by electric birefringence". Thesis, London South Bank University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336307.
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Persons, Andrea Karen. "Use of the Lowry and Bradford Protein Assays to measure bacterial abundances in a sandstone reservoir". Master's thesis, Mississippi State : Mississippi State University, 2003. http://library.msstate.edu/etd/show.asp?etd=etd-11102003-120611.
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Bose, Himangshu Sekhar. "Metachromatic behaviour of some thiazine dyes in solution in presence of inorganic and organic electrolytes, surfactants, polyelectrolytes and clay minerals". Thesis, University of North Bengal, 1986. http://hdl.handle.net/123456789/731.
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Akar, Dilek Shahwan Talal. "Physicochemical characterization of the sorption behavior of Cs+ and Sr2+ Ions on natural kaolinite and cliptilolite minerals/". [s.l.]: [s.n.], 2005. http://library.iyte.edu.tr/tezler/master/kimya/T000489.pd.
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ZHANG, JING. "INTERACTION OF METHANOGENS WITH CLAY MINERALS, ORGANIC MATTER, AND METALS". Miami University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=miami1389881682.
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Liu, Jibin. "Heteroaggregation of Silver Nanoparticles with Clay Minerals in Aqueous System". The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1408927952.
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Zhao, Linduo. "Iron redox process in clay minerals and its environmental significance". Miami University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=miami1438388284.
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Olson, Tyler Lee. "Reduction of nitroaromatic compounds by iron(ii) reduced clay minerals". Thesis, University of Iowa, 2014. https://ir.uiowa.edu/etd/1375.
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Vlack, Yvette A. "A Diffuse Spectral Reflectance Library of Clay Minerals and Clay Mixtures within the VIS/NIR Bands". Kent State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=kent1227006436.
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Andrea, Martijn. "The anisotropic elastic properties of clay-rich rocks". Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243413.
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Rêgo, Eric Siciliano. "Variation of minerals and clay minerals recorded in the Neo-Tethys (central Turkey): new evidence of climatic changes during the middle Eocene". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/21/21136/tde-23032018-152550/.
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Minerals and clay minerals in continental sedimentary successions are valuable tools for reconstructing past environmental conditions. Given the state of preservation of clays minerals, it is possible to identify how they were formed, providing clues about continental weathering conditions (inherited minerals) and geochemical conditions in the water column (neoformed or transformed). This study presents new mineralogical data from the Baskil section, a highly preserved middle Eocene succession in the Neo-Tethys (central Turkey). A gradual shift from a well-crystalline illite and chlorite interval (subsection I) to a detrital smectite dominant interval (subsection II) characterizes a change in source area from metamorphic to igneous rocks and changes from physical to chemical weathering conditions on land. This period coincides with the Middle Eocene Climatic Optimum (MECO), indicating a mineralogical signature of the event. Higher content of terrigenous input being deposited from 40.5 to 40 Ma caused a dilution effect of the carbonate materials as calcite and dolomite significantly decreases. Authigenic palygorskite showed an increasing trend from the middle to the uppermost portion of the section, indicating favorable conditions in the water column for its formation. We assume that conditions in the ocean circulation changed after 40 Ma, forming a stratified water column with warmer and saline conditions at greater depths, favoring palygorskite and possibly authigenic dolomite precipitation. The mineralogical evolution of the Baskil section reflects how sources and weathering regimes changed through time, and how these changes can be related to global (i.e. MECO) and/or local to regional processes.Minerais e argilominerais em sucessões sedimentares são excelente ferramentas para a reconstrução de condições ambientais. Dado o estado de preservação dos argilominerais, é possível identificar como eles foram formados, fornecendo informação sobre as condições de intemperismo no continente e sobre condições geoquímicas na coluna d\'água. Este estudo apresenta novos dados mineralógicos da seção de Baskil, uma sucessão do Eoceno médio altamente preservada no Neo-Tethys (Turquia central). Uma mudança na assembléia mineralógica com maiores concentrações de ilita e clorita (subseção I) para um intervalo dominante de esmectita detrítica (subseção II) caracteriza uma mudança na área de fonte de rochas metamórficas para rochas ígneas e mudanças de condições de intemperismo físico para intemperismo químico. Este período coincide com o Ótimo Climático do Eoceno Médio (MECO), indicando uma assinatura mineralógica do evento. A paligorsquita autigênica teve um aumento na porção media e superior da seção, indicando condições favoráveis na coluna de água para a sua formação. Possívelmente as condições na circulação do oceano naquela região mudaram após 40 Ma, formando uma coluna de água estratificada com condições mais quentes e salinas em profundidades maiores, favorecendo precipitação de paligorsquita e dolomita. A evolução mineralógica da seção de Baskil reflete como as fontes e os regimes de intemperismo mudaram ao longo do tempo, e como essas mudanças podem estar relacionadas aos processos globais (e.g. MECO) e /ou a processos locais e regionais.
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Stirner, Manuela [Verfasser], i Josef [Akademischer Betreuer] Breu. "Clay linked Gels : Mechanical Enhancement of Hydrogels by Incorporation of Clay Minerals / Manuela Stirner. Betreuer: Josef Breu". Bayreuth : Universität Bayreuth, 2014. http://d-nb.info/1095663593/34.
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Sato, K. "Local Molecular Structures Induced by Water Adsorption/Desorption in Smectite Minerals". Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35185.
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Positronium (Ps) annihilation spectroscopy and thermogravimetry and differential thermal analysis
(TG-DTA) were conducted for synthetic smectite clay minerals to investigate local molecular structures induced
by water adsorption and desorption. The TG curves indicate the weight loss of ~ 3.5 wt %, ~ 2.5 wt %,
and ~ 2.0 wt % for saponite, hectorite, and stevensite due to dehydration, in accordance with DTA endothermic
peaks around 332 K, 350 K, and 345 K. It is found based on the results of Ps lifetime spectroscopy
that the presence of angstrom-scale open space is sensitively dependent on water adsorption and desorption
in smectite clay minerals.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35185
31
Villemure, Gilles. "Photochemical applications of the intercalation of organic cations in clay minerals". Thesis, University of Ottawa (Canada), 1987. http://hdl.handle.net/10393/21389.
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Chermak, John Alan. "The kinetics and thermodynamics of clay mineral reactions". Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54505.
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The diagenesis of rocks during burial occurs in response to changing temperature, pressure, and solution composition. Due to their geologic abundance, high surface area, and reactivity clay minerals are important participants in the diagenesis of clastic rocks. The kinetic and thermodynamic stability of clays is in general poorly understood. This dissertation research measured the rate of transformation of kaolinite to muscovite/illite and developed a method to estimate clay mineral thermodynamic stability.
Clastic rock diagenesis is controlled by the rates of silicate mineral growth and transformation. Marine mudstones commonly contain large proportions of kaolinite which reacts during diagenesis to form muscovite/illite and/or chlorite. Batch reactor experiments were used to measure the reaction rate of 1.5 kaolinite + K⁺ = muscovite + H⁺ + 1.5 H₂O using the initial rate method and a fitted form of the integrated rate equation. Experiments were performed at temperatures ranging from 250° to 307°C with solutions of 0.5 - 2.0 m KCl. These results can then be extrapolated to diagenetic temperatures using the Arrhenius equation.
ln addition, a technique was developed to estimate the ΔGf0 and ∆Hf0 of silicate minerals. Silicate minerals have been shown to act as a combination of basic polyhedral units (Hazen 1985 and 1988). This work showed that their thermodynamic properties could be modeled as the sum of polyhedral contributions. A multiple linear regression model was used to find the contribution of the oxide and hydroxide components (gᵢ and hᵢ) to the ΔGf0 and ∆Hf0 of a selected group of aluminosilicate minerals at 298 K. The ΔGf0 and ∆Hf0 of other silicate minerals can be estimated from a weighted sum of the contribution of each oxide and hydroxide component (gᵢ and hᵢ). These results can be also used to estimate the ΔGf0 of silicate minerals at higher temperatures (up to =600 K) by using the equation,
gᵢ(T)= hᵢ(298) - T((hᵢ(298)-gᵢ(298))/298)Ph. D.
33
Hall, Anne Marie. "The clay mineralogy of the lower San Andres formation, Palo Duro Basin, Texas". Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/25880.
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Neumann, Anke. "Assessing the redox reactivity of ferrous iron species associated with clay minerals /". Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18056.
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Jaisi, Deb Prasad. "Fe(III) reduction in clay minerals and its application to technetium immobilization". Oxford, Ohio : Miami University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1179946951.
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Daneshvar, Ehsan. "Role of provenance on clay minerals and their distribution in modern estuaries". Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540028.
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Roch, Gabriela Ellen. "A solid state NMR investigation of the thermal transformations of clay minerals". Thesis, University of Kent, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297345.
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Castro, Smirnov Fidel Antonio. "Physicochemical characterization of DNA-based bionanocomposites using nonafibrous clay minerals : biological applications". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112260/document.
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Parmi les différents minéraux argileux, la sépiolite, qui est un silicate fibreux naturel, est un potentiel nano-transporteur prometteur pour le transfert non-viral de biomolécules. Il a en effet été montré que la sépiolite interagissait avec des molécules biologiques telles que les lipides, les polysaccharides et les protéines. Dans ce travail, nous démontrons que la sépiolite interagit également efficacement avec différents types de molécules d'ADN (génomique, plasmidique, oligonucléotides simple et double brin), et nous présentons la première étude détaillée sur les mécanismes d'interaction entre la sépiolite et l'ADN, ainsi qu’une caractérisation physico-chimique de bionanocomposites ADN-sepiolite. Une analyse spectroscopique a montré tout d’abord que l’interaction de l'ADN avec la sépiolite était plus forte en présence de polycations, la valence de ces derniers accroissant le rendement d’absorption, et deuxièmement, que l'ADN ainsi adsorbé pouvait être récupéré avec un rendement modulé par la présence d’EDTA, la structure de l'ADN et son activité biologique étant conservées. Par spectroscopie infrarouge à transformée de Fourier (FTIR) nous avons identifié les groupes silanol externes comme les principaux sites d'interaction avec l'ADN. Nous avons ensuite prouvé qu'il est possible d'utiliser la sépiolite pour extraire l'ADN de bactéries, pour la purification de l'ADN et pour la purification de toute contamination bactérienne. En combinant la microscopie à fluorescence, la microscopie électronique à transmission (MET), la vidéo-microscopie et l’analyse par cytométrie en flux (FACS), nous avons montré que la sépiolite peut être spontanément internalisée dans des cellules de mammifère par le biais de deux voies, l’endocytose et la macropinocytose. En tant que preuve de concept, nous montrons que la sépiolite est capable de transférer de manière stable l'ADN de plasmide dans des bactéries et des cellules de mammifères. Il a également été prouvé qu’en incubant des bactéries avec des bionanocomposites ADN-sepiolite, initialement préparés en présence d'une faible concentration en cations divalents et avec de la sépiolite traitée aux ultrasons (sSep), il était possible d'augmenter l'efficacité de la transformation bactérienne 20 à 30 fois par rapport aux méthodes basées sur l'«effet Yoshida». En outre, nous montrons que l'efficacité du transfert de gènes par la sépiolite peut être optimisée : l'utilisation de sSep et l'exposition à la chloroquine augmentent d’un facteur 100 et 2, respectivement, l’efficacité de transfection. Ces résultats ouvrent la voie à l'utilisation de bionanocomposites à base de sépiolite comme de nouveaux potentiels nano-transporteurs hybrides potentiels, à la fois pour la thérapie génique et le développement de nouveaux modèles biologiques en sciences fondamentales et appliquéesAmong the various clay minerals, sepiolite, which is a natural fibrous silicate, isa potential promising nanocarrier for the non-viral transfer of bio-molecules. Indeed,sepiolite has been shown to interact with biological molecules such as lipids,polysaccharides and proteins. Here, we show that sepiolite efficiently binds differenttypes of DNA molecules (genomic, plasmid, single strand and double strandoligonucleotides), introducing the first detailed study on the interaction mechanismsbetween sepiolite and DNA, as well as the physicochemical characterization of theresulting DNA-sepiolite bionanocomposites. The interaction mechanisms aresuggested to be electrostatic interactions, van der Waals forces, cation bridges, andhydrogen bonding. Spectroscopy analysis showed that the binding of DNA to sepiolitewas increased by polycations with valence dependent efficiency, and the DNApreviously adsorbed could be recovered with an efficiency that could be modulatedusing a chelating agent (EDTA), preserving the DNA structure and biological activity.Fourier-transform infrared spectroscopy identified the external silanol groups as themain sites of interaction with the DNA. It was proved that it is possible to use sepiolitefor extracting DNA from bacteria, for DNA purification and for purification from bacterialcontamination. By combining fluorescence microscopy, transmission electronmicroscopy (TEM), time-lapse video microscopy and flow cytometry analysis (FACS),we show that sepiolite can be spontaneously internalized into mammalian cells throughboth endocytic and non-endocytic pathways. As a proof of concept, we show thatsepiolite is able to stably transfer plasmid DNA into bacteria and mammalian cells. Itwas also proved that with the incubation of bacteria with the Sep/DNAbionanocomposite initially prepared in the presence of a low concentration of divalentcation, and using sonicated sepiolite (sSep), it is possible to increase the bacterialtransformation efficiency from 20 to 30-fold compared to previously reported methodswhich are based in the “Yoshida effect”. Additionally, we show that the efficiency ofsepiolite-mediated gene transfer can be optimized: the use of sSep and the exposureto the endosome disrupter chloroquine 100-fold and 2-fold stimulated DNA transfectionefficiency, respectively. These results open the way to the use of sepiolite-basedbionanocomposites as a novel class of hybrid nanocarriers for both potential genetherapy and the development of novel biological models of interest for academic andapplied sciences
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Paiva, Lucilene Betega de. "Estudo do potencial de bentonitas nacionais e argentinas na obtenção de bentonitas organofilicas em dispersão aquosa e meio semi-solido visando a aplicação em nanocompositos polimericos". [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267122.
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Orientador: Ana Rita MoralesTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Sete bentonitas foram avaliadas quanto ao potencial na obtenção de formas organofílicas, através da caracterização por difração de raios-X para avaliar os espaçamentos basais, pelo teste de inchamento, em água e em xileno, para avaliar o caráter a hidrofílico e organofóbico, por energia dispersiva de raios-X para identificar os elementos presentes, e da capacidade de troca de cátions pelo método de adsorção do azul de metileno. Somente uma não apresentou potencial para organofilização e foi descartada. As bentonitas que apresentaram potencial para serem organofilizadas, foram tratadas com um sal quaternário de amônio por troca de cátions em dispersão aquosa, metodologia convencionalmente usada, e intercalação em meio semi-sólido, como metodologia alternativa. Posteriormente, as bentonitas foram caracterizadas por difração de raios-X, para avaliar intercalação dos cátions orgânicos, pelo teste de inchamento, em água e em xileno, para avaliar o caráter organofílico e hidrofóbico adquirido, por energia dispersiva de raios-X para identificação dos elementos presentes. Adicionalmente, ambas bentonitas sódicas e organofilizadas, foram caracterizadas por análise termogravimétrica para avaliar a estabilidade térmica e o teor de cátions orgânicos incorporado, por microscopia eletrônica de varredura para avaliar a morfologia das partículas e por medida da área específica baseada na adsorção de nitrogênio. Todas as bentonitas adquiriram caráter organofílico. Foram preparados nanocompósitos com polipropileno e as bentonitas organofílicas obtidas. Após o processamento, foi feita uma caracterização por difração de raios-X e por microscopia eletrônica de transmissão para avaliar a dispersão das bentonitas organofílicas na matriz polimérica e o tipo de estrutura formada. Foram obtidos nanocompósitos com estruturas esfoliadas, parcialmente esfoliadas e intercaladas, e intercaladas. O estudo mostra uma grande potencialidade das bentonitas em estudo na obtenção de bentonitas organofílicas para nanocompósitos poliméricos, bem como a eficiência da metodologia de organofilização em meio semi-sólido.
Abstract: Seven bentonites were evaluated to verify the potential to obtain the organophilic clay. The characterization by X-ray diffraction to evaluate the basal spacings was made, as well as the characterization by swelling capacity test, in water and in xylene, to evaluate the hydrophilic and organophobic character, by X-ray dispersive energy to indentify the present elements, and by cations exchange capacity using the method of blue methylene adsorption. Only one bentonite didn't show potential to be organophilized and was rejected. The bentonites that showed potential to be organophilized, were treated with a quaternary ammonium salt by cation exchange in aqueous dispersion, the conventional methodology used, and by intercalation in semi-solid medium, as an alternative methodology. Subsequently, they were characterized by X-ray diffraction, to evaluate the intercalation of the organic cations, by the swelling capacity test, in water and in xylene, to evaluate the organophilic and hidrophobic acquired, by X-ray dispersive energy to identify the present elements. Furthermore, both sodium and organophilized bentonites were characterized by thermogravimetric analysis to evaluate the thermal stability and the tenor of organic cations incorporated, by scanning electronic microscopy to evaluate the morphology of the particles, and by measurement of specific area based on the adsorption of nitrogen. All bentonites acquired organophilic character. Nanocomposites with polypropylene as matrix and the organophilic bentonites obtained were prepared. After the processing, a characterization by X-ray diffraction and by transmission electronic microscopy to evaluate the dispersion of the organophilic bentonites in the polymeric matrix and the type of structure formed were made. Nanocomposites with exfoliated, or partially exfoliated and intercalated, and intercalated structures were obtained. The study shows a large potential of the bentonites in study in obtaining organophilic bentonites for polymeric nanocomposites, as well as the efficiency of the methodology of organophilization in semi-solid medium.
Doutorado
Ciencia e Tecnologia de Materiais
Doutor em Engenharia Química
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Morkel, Jacqueline. "Kimberlite weathering mineralogy and mechanism /". Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-07212007-104241.
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Velazquez, Tzayhri Gallardo. "A study on pillared clays". Thesis, University of Salford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252970.
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McConville, Caspar J. "Related microstructural development on firing kaolinite, illite and smectite clays". Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299540.
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Bowman, Ryan Lee. "CLAY MINERAL TRANSFORMATIONS IN ACIDIC ENVIRONMENTS: FINDING AN EARTHEN ANALOGUE TO THE SURFACE OF MARS". OpenSIUC, 2019. https://opensiuc.lib.siu.edu/theses/2608.
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Once similarities between Earth and other terrestrial bodies were discovered, determining the conditions that contributed to the evolution of surface processes on these planets, particularly Mars, is of great interest. More importantly, such research and exploration can provide proof of previous existent life within these near-surface environments. As the past environmental conditions at Mars’ surface are mostly unknown, studies of comparable environments on Earth have been crucial toward deciphering the overall geological understanding of Mars. As the discovery of past conditions on Mars become more absolute, researchers can search for more constrained bio-signatures of life that may have been present. Using the geological similarities between Earth and Mars, analogues can be used to compare the conditions on Mars and Earth and how they evolved over time, further providing more precise understanding of our own environment as it relates to the future. In this study, acid mine drainage (AMD) systems, which are one of the most acidic environments on Earth, were compared to the surface of Mars as a potential analogue to the past conditions of the planet when such acid-impacted environments were widespread at the surface of the planet.
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Wilcox, Jeffrey Kendall. "Influence of pH on zinc adsorption by kaolinite, montmorillonite, and Londonderry clay". Thesis, The University of Sydney, 1994. https://hdl.handle.net/2123/26746.
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The adsorption of zinc ions as a function of pH and total dissolved metal concentration was experimentally investigated for three types of clays (kaolinite. montmonllonite. and Londonderry). The results indicate increases in adsorption of the zinc ions occurs with increases in pH for each of the three clays. Langmuir and Freundlich isotherms were created for each of the clay types.
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Mashburn, Courtney Dyan. "Laboratory studies on the heterogeneous chemistry of clay minerals in the Earth's atmosphere". Diss., Connect to online resource, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3239413.
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Zhao, Qian. "Molecular dynamics simulation of interactions between clay minerals and a controlled organic phase". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47650.
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Engineered organoclays are 2:1 phyllosilicate soils that have been synthesized with a controlled interlayer organic phase to exhibit enhanced strength, lower compressibility, and stronger retention of organic compounds. Engineered organoclays are highly sorptive, and have a variety of potential engineering applications as sorbents or amendments in engineered earthen barrier systems. Previous studies examined the impact of the organic coating on a soil's physical properties; however, the geochemical behaviors of organoclays, especially their interaction with organic compounds at the micro-scale, remained relatively unquantified. This study investigated the engineering behavior of montmorillonite modified with a variety of quaternary ammonium cations (QAC clays) with controlled structure and density of loading. Molecular dynamics simulations were used to model the surfactant arrangement, geochemical processes in the QAC-clay interlayer, including organic compound sorption and mass transport, as well as the surface electrokinetics of suspended QAC-clay particles. All simulations were carried out based on the combined force field of ClayFF and the Consistent-Valence Force Field to ensure the accuracy of the simulation results, and results yielded insight into the prediction of synthesized QAC-clay behaviors as sorptive material for non-polar organic compounds.
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Geatches, Dawn Lesley. "Clay minerals and their gallery guests : an ab initio investigation into their interactions". Thesis, Durham University, 2011. http://etheses.dur.ac.uk/749/.
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Clay minerals are ubiquitous and readily accessible in the natural environment and consequently have become an essential ingredient in the development of Western Society. Their structural properties are responsible for many of their uses, their layered-leaf composition enables the absorption of water and other solutes, for example. In this thesis, the focus of interest lies primarily in the chemical properties of the clay minerals, which is due to the large surface areas of varying atomistic environments comprising the mineral layers. Clay minerals offer a challenge to the electronic structure modeller as their atomistic composition is non-exact, consequently a number of constraints are automatically applied during the modelling process, the first being the choice of composition of the model. There are currently few examples of density functional theory studies using planewaves and the pseudopotential approximation, and the available experimental data is not necessarily directly applicable to theoretical data due in part, to the inexactness of the clay mineral composition. Consequently, in the studies presented in this thesis, as much time has been spent in considering the modelling methods as on the results obtained and the implication of these in the modelling environment chosen. This thesis records investigations into the decarboxylation of a fatty acid into an alkane and CO$_{2}$ with the modelling of a catalytic environment of an aluminium-bearing clay mineral; the identification of a transition state of this reaction pathway using lattice dynamics and finally, the mechanism of reduction within iron-bearing clay minerals.
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Bakker, Eleanor. "The impact of plant growth and potassium uptake on clay minerals in soil". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAU012/document.
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Le potassium est un nutriment essentiel à la croissance et au développement des plantes. Les minéraux argileux dans les sols représentent un important réservoir de K disponible pour les plantes. L'extraction de K fixé à partir de l'espace interfoliaire des minéraux micacés 2:1 peut entraîner une augmentation de la distance feuillet à feuillet qui peut être mesurée par diffraction des rayons X . Des échantillons de l'expérience Morrow Plots continue avec du maïs (C) ou du maïs-avoine-foin (R), provenant de sous-parcelles fertilisées (F) et non fertilisées (U) pour les années 1904, 1957, 1980, 1997 et 2013-2014, ont été soumis au fractionnement granulométrique séquentiel pour obtenir la fraction limoneuse (50-2 um) et les sous-fractions argileuses (2-0,2, 0,2-0,05 et <0,05 um). Les résultats granulométriques montrent une hétérogénéité significative malgré la petite taille de la MP, et un gain de sous-fraction < 0,05 um avec le temps. La modélisation des diagrammes de diffraction des rayons X a été effectuée pour obtenir une identification concluante de l'assemblage de minéraux argileux et évaluer l'impact de 110 ans d'agriculture continue et de différentes pratiques agronomiques. Un assemblage complexe de minéraux argileux a été identifié avec jusqu'à onze contributions différentes nécessaires pour reproduire les données expérimentales de sous-fractions de moins de 2 um, y compris jusqu'à six couches mixtes d'illite-smectite-chlorite. L'analyse de phase quantitative pour toutes les sous-parcelles et toutes les années, a montré que l'assemblage minéral du MP est similaire entre les différentes sous-parcelles, quel que soit le traitement agronomique. Aucune preuve significative d'altération ou de transformation des phases minérales argileuses n'a été observée au fil du temps. La nature dioctaédrique des minéraux argileux de la MP désavantage l'extraction du K et donc la dissolution est le mécanisme privilégié pour l'absorption du K et la perte de sous-fractions 2-0,2 et 0,2-0,05 um est attribuée à ce processusPotassium is an essential nutrient for plant growth and development. Clay minerals in soils represent an important reservoir of plant-available K. Extraction of fixed K from the interlayer space of micaceous 2:1 minerals can lead to an increase in the layer-to-layer distance which can be measured by X-ray diffraction. Samples from the Morrow Plots continuous corn (C) and corn-oats-hay (R) experiment, from fertilised (F) and non-fertilised (U) subplots for the years 1904, 1957, 1980, 1997 and 2013-2014 were subjected to sequential size-fractionation to obtain the silt fraction (50-2 um) and clay-sized subfractions (2-0.2, 0.2-0,05 and <0.05 um). Granulometric results show siginificant heterogeneity despite the small size of the MP, and a gain in <0.05 um subfraction with time. Full-profile fitting of X-ray diffraction patterns was performed to obtain conclusive identification of the clay mineral assemblage and assess the impact of 110-years of continuous agriculture and different agronomic practices. A complex clay mineral assemblage was identified with up to eleven different contributions necessary to reproduce the experimental data of <2 um subfractions, including up to six illite-smectite-chlorite mixed-layers. Quantitative phase analysis for all subplots and years showed that the mineral assemblage of the MP is similar between different subplots, regardless of agronomic treatment. No significant evidence of alteration or transformation of clay mineral phases was observed over time. The dioctahedral nature of the clay minerals of the MP disfavours K-extraction and thus dissolution is the favoured mechanism for K-uptake and the loss of 2-0.2 and 0.2-0.05 um subfractions is attributed to this process
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Sharma, Alok. "Molecular Dynamics simulation of rock and clay minerals to estimate their mechanical properties". Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/40928.
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Macroscopic analyses of rocks have produced acceptable results for many problems. These problems are simple, involving normal conditions. But a need is arising to study these rocks under extreme conditions, like high temperatures, projectile penetration and extreme pressures. Behavior of rocks under these conditions cannot be predicted using common macroscopic analyses at normal conditions. Nanostructure of the rock governs the behavior of rock under such situations. Hence, there is a need to study these materials using micro molecular mechanics.
There is also a theory that failure in a rock mass is governed by the formation and propagation of microscopic cracks. The development of these can be observed and studied using the nanoscale analyses. A new science is emerging which deals with manipulating the nanostructure of materials. It may be possible in near future to improve the properties of materials into more desirable ones, by changing their nanofabric. These prospects make the nanoscopic analyses of rocks very intriguing.
This research aims at developing methods to analyze rocks, clays and other geotechnical materials to study their nanolevel properties. Molecular Dynamics simulation is the most commonly used method in molecular mechanics. A software program TINKER was used for developing the simulation. Using this, MD simulation was performed on a (14,1) carbon nanotube for validation purposes. Later on simulations were performed on rock minerals such as quartz, albite and calcite and clays such as kaolinite and palygorskite. The simulated results are compared with published data on mechanical properties of rock and clay minerals.Master of Science
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Lewis, Tara Marie. "Sorption of metals to clay minerals in the presence of complexing organic ligands". Thesis, Loughborough University, 2008. https://dspace.lboro.ac.uk/2134/34211.
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In recent years several models have been developed that have been used to predict the partitioning of a solute (metal or organic ligand) between water and a geological solid. These predictions are necessary for calculations of risk assessment associated with a deep underground nuclear waste repository. This thesis includes a review of international literature related to the reactions of metallic radionuclides with complexing organic ligands that may be present in and around a repository and the effect of these complexants on the sorption of radionuclides onto solids. The complexants include decontamination agents (EDTA, NTA and picolinic acid), degradation products of cellulose (ISA and gluconic acid), and humic and fulvic acids (HA and FA respectively) that may be present in the natural environment. The experimental work presented in this thesis uses a batch method to produce a comprehensive dataset of distribution ratios for the sorption of trace radioactive metals (Eu3+, Ni2+, Cd2+, Fe2+, and Cs+) in the presence, and absence, of organic complexants onto solid mineral phases (montmorillonite, kaolinite and goethite).