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Showing 1 to 20 of 28 for “"uranyl"”.
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Precipitation and Dissolution of Uranyl Phosphates in a Mircofluidic Pore Structure
… was chernikovite (also known as hydrogen uranyl phosphate; UO2HPO4), even though the formation of other minerals were thermodynamically favored depending on the experimental conditions. Precipitation and dissolution rates varied with influent conditions. Relative to when only U(VI) and …
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URANYL DEPOSITION IN UNCONFORMITY-RELATED DEPOSITS IN THE ATHABASCA BASIN: EVIDENCE FROM URANIUM SPECIATION IN HEMATITE AND GOETHITE
… modeling demonstrated uranium transport as uranyl (UO22+) species in hypersaline fluids in the Athabasca basin. Electron microprobe analyses reveal that hematite inclusions in two early generations of secondary quartz overgrowth, as well as some disseminated hematite in clay mineral …
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Uranium isotopic fractionation induced by U(VI) adsorption onto common aquifer minerals
… factors accompanying the adsorption of uranyl, uranyl hydroxyl, uranyl carbonato, and calcium uranyl carbonato ions. To increase our ability to resolve fractionation, experiments were carried out with a multi-stage, batch approach, in which a U(VI)-bearing solution was exposed to three …
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Separation and Coordination Chemistry of Actinides
… involved the hydrothermal coordination of the uranyl cation to a number of small ligands, which resulted in the eleven luminescent coordination complexes described in those chapters. Of particular interest are the structures containing mixed-valent U3O8 layers generated in situ in chapter II, …
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The synthesis and properties of some chelating ion exchangers.
… constants for the metal-resin complexes, uranyl and copper-poly styrene chelates, has been made. It has been shown that the uranyl values lie somewhat lower than the stability constants of the corresponding metal-monomor complexes, whilst the copper values are of the same order as the …
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Interaction of aqueous U(VI) with goethite, montmorillonite, and UO2(s)
… following a systematic roadmap. Goethite-uranyl-carbonate ternary surface complexes were required in every model. A triple plane model with a dimeric goethite-uranyl complex was found to provide the best fit, but the performance of a double layer model with bidentate goethite-uranyl and …
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Engineering Superparamagnetic Iron Oxide Nanoparticles for Environmental Applications
… are demonstrated as a platform material for uranyl sorption and separation from water. Specifically, (bilayer) surface optimized, 8-30 nm monodisperse IONPs demonstrate ultra-high uranyl sorption capacities (>50% by wt/wt in some cases). Synchrotron-based X-ray absorption spectroscopic (EXAFS …
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Quaternary structures of the cyanide dihydratases of Bacillus pumilus C1 and Pseudomonas stutzeri AK61
… micrographs of enzyme particles stained in uranyl acetate. Each enzyme consists of a spiral structure of well-defined length. It is proposed that this arrangement of subunits occurs in many other nitrilases and that a number of unexplained observations in the literature can reconciled by …
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Metallo-supramolecular Architectures based on Multifunctional N-Donor Ligands
… In the second part of the thesis, novel uranyl complexes of the bis(2-hydroxyaryl) imine ligands have been synthesized and characterized. 1D coordination polymers and mononuclear structures were formed. In all complexes a distorted hexagonal bipyramidal coordination geometry around the …
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ΠΡΟΣΡΟΦΗΣΗ U, TH, BA ΚΑΙ CS ΑΠΟ ΟΡΥΚΤΑ ΤΗΣ ΑΡΓΙΛΛΟΥ ΚΑΙ ΣΥΝΘΕΤΙΚΑ ΟΡΥΚΤΑ-ΕΚΛΕΚΤΙΚΟΤΗΤΑ ΚΑΙ ΔΕΣΜΕΥΣΗ ΤΟΥ CS
THE BEHAVIOUR OF VERMICULITE AS ADSORBENT OF URANYL IONS WAS FOUND TO BE IDENTICAL TO MONTMORILLONITE, WHEREAS THE QUANTITY OF THE ADSORBED HYDROXY. THE IONS WAS MUCH LOWER THAN ITS THEORETICAL CATION EXCHANGE CAPACITY. THE LATER IS ATTRIBUTABLE TO A BLOCKING OF VERMICULITE'S CATION EXCHANGE …
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Bacterial influence on uranium oxidation reduction reactions : implications for environmental remediation and isotopic composition
… produces manganese oxides with can both adsorb uranyl and partially oxidize UO2. Determination of if and how bacteria can influence the oxidation of uranium is important because oxidation will increase the solubility and mobility of uranium in the environment.
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The Uranium Mineralization of the Macusani District, Southeast Peru: Mineralogy, Geochemistry, Geochronology and Ore-Genetic Model.
… of low-temperature fluids and interaction of the uranyl ion with Fe- and Mn-mineraloids.Thus, although the Macusani U deposits are volcanic-hosted, they differ radically from documented magmatic-hydrothermal systems.
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Bacterial acid phosphatase and its application to waste remediation and metal recovery
… Previous studies using biogenic hydrogen uranyl phosphate (HUP) on Serratia sp. removed \(^{60}\)Co, \(^{137}\)Cs and \(^{90}\)Sr via intercalative ion exchange into the HUP crystal lattice. Due to their non toxic and non radioactive nature, zirconium phosphates offer an alternative to HUP …
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Computational Modeling and Design of Protein and Polymeric Nano-Assemblies
… an aggregation prone peptide assembly to bind uranyl and (ii) a protein construct to encapsulate a zinc porphyrin derivative with unique photo-physical properties. Additionally, molecular dynamics simulations are used to investigate purely synthetic assemblies of (iii) highly charged …
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Dry process fluorination of uranium dioxide using ammonium bifluoride
… in argon produced uranium tetrafluoride, with uranyl difluoride, ammonium diuranyl pentafluoride and triuranium octoxide as impurities. Minimum temperatures and times needed to decompose the double salt in the fluidized beds were 200 minutes at 115 °C, a 500-minute ramp to 425 °C, and 200 …
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Ionic liquids and chitinous biomass: materials, synthesis, and applications for uranium sequestration
… with the amidoxime functional group for aqueous uranyl ions. While these research efforts have demonstrated chitin as a versatile polymer back-bone for fiber applications for U recovery, complexity of the waste derived feedstock is challenging and other chemical components that remain in the …
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THE DETERMINATION OF TRACE METALS BY CAPILLARY ELECTROPHORESIS
… chemistry on the peak shape of the migrating uranyl-arsenazo III was also studied using fused silica capillaries with two different internal coatings and three polymeric capillaries. A study was also carried out on the construction and investigation of a post-capillary reactor for the …
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Computational investigations of the electronic structure of molecular actinide compounds
… compounds. In chapter five, group 15 and 16 uranyl analogues have been investigated. For the UE2 (E = O, S, Se, Te) analogues the geometry bends for all chalcogens heavier than O. The UE2 2+ analogues remain linear all the way down group 16. In U(NCH3)2 2+ the formation of a {pi} “back bone” …
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