2 edition of Uranium solubility, speciation and complexation at high pH found in the catalog.
Uranium solubility, speciation and complexation at high pH
Thesis (Ph.D.) - Loughborough University, 1999.
|Statement||by Mark Sutton.|
The high levels observed for soluble calcium, in these soils. The increase in the total uranium levels with increasing carbonate levels is due to the complexation of uranium with carbonate species. Geochemical modeling confirms that the The determination of solubility and chemical speciation will provide vital information. the effect of phosphate on the migration of uranium in natural waters is not well understood. We have investigated the solubility of a well-characterized U(VI)-phosphate phase in the pH range 3 to 9: (U02)3(P04)2 - 4H20(s) Analysis of these data indicates the formation of the predominant species U02HP04(aq) and U02PO; in the pH range
Bacillus sphaericus JG-A12 is a natural isolate recovered from a uranium mining waste pile near the town of Johanngeorgenstadt in Saxony, Germany. The cells of this strain are enveloped by a highly ordered crystalline proteinaceous surface layer (S-layer) possessing an ability to bind uranium Cited by: Investigation of uranium redox chemistry and complexation across the pH range by cyclic voltammetry TZ (GMT) by Mei Chew The current option for the management of Intermediate-Level Waste (ILW) and High-Level Waste (HLW) in the UK is to store it in stainless steel containers and then placed in a deep underground Geological Author: Mei Chew.
dominate uranium speciation in mid- to high-pH solutions. The tendency for these uranyl complexes to remain in solu-tion has led to the common assumption that such aqueous complexation causes a high degree of uranium mobility (8, 9). Furthermore, the presumed mobility of these uranyl complexes represents the basis of proposed remediation. A lower value of the solubility product of the uranium dioxide phase deﬁned as fuel in the SKB uranium database provides reasonable solubilities for a wide span of experimental results at near to neutral pH. Based on the modeling and using the b1,4 for the U(IV)-OH complexation given by Grenthe et al. (a), a logKs0 (UO2(s) 1 4H 1 NU41 1 2H.
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Uranium solubility, speciation and complexation at high pH Low level nuclear waste arising from UK nuclear sites, research establishments, hospitals and industry is currently disposed of at the Drigg Disposal Facility in by: 6.
Studies have also been perforined to measure uranium sorption by grout material at high pH in the presence of the above ligands. This work makes a significant contribution to the understanding of uranium solubility and speciation in waters. at high pH and under conditions relevant to low level nuclear waste by: 6.
Uranium solubility, speciation and complexation at high pH. By Mark Sutton. Get PDF (16 MB) sodium\ud and potassium and produce waters of a high pH. Aerobic environments are\ud expected to dominate over the early period of the vault life, after which the\ud combined effect of canister corrosion and microbial activity will lead to anaerobic Author: Mark Sutton.
By Uranium Solubility, C Mark Sutton and Mark Sutton. Abstract. speciation and complexation at high pH This item was submitted to Loughborough University's Institutional Repository by the/an author Year: OAI identifier: oai: Uranium occurred predominantly sorbed onto phyllosilicates in the deeper vadose zone and groundwater; sorbed uranium was also an important component at intermediate depths.
Since the calcite-bearing pond sediments speciation and complexation at high pH book been removed in remediation efforts, uranium fate and transport will be controlled primarily by desorption of the sorbed uranium and dissolution of by: However, this study has demonstrated that solubility in leachate could rise at high pH and high carbonate levels, if aerobic conditions were to develop.
Soluble U(VI) species would be formed. The results presented in this work show that gluconate increases significantly the uranium solubility at pH c = 12; the study of U(VI) speciation in alkaline solutions is complex, mainly due to formation of sparingly soluble uranates of varying compositions (e.g.
sodium and potassium uranates). UV–Vis measurements in the alkaline pH range Cited by: 7. Possible complexation of uranium with dissolved humic substances in pore water of marine sediments. Science of The Total Environment, DOI: /(92) M. Saleem, M.
Afzal, Riaz Qadeer, Javed by: At high pH, low uranium adsorption is attributed to increasing carbonate concentrations, leading to weakly sorbing or non-sorbing aqueous U(VI)-carbonate complexes (Hsi and Langmuir,Waite et al.,Davis et al., ).Cited by: orthorhombic, tetragonal and in body-centered cubic ones .
Uranium exhibits a high melting point ( C) and it is one of the heaviest naturally occurring elements. The density of uranium ( g cm−3) is 65% higher than that of lead [12, 14].
Uranium can be prepared from its oxide via reduction by calcium or Size: KB. Sorption and Speciation of Uranium on Silica Colloids lifetimes of the two uranium complexes on the surfaces quoted by Gabriel et al.
[ 9 ] are 25 m s and 50 m s and are longer than. The enthalpies of complexation for two successive complexes, [CaUO 2 (CO 3) 3] 2− and [Ca 2 UO 2 (CO 3) 3](aq), were determined for the first time by microcalorimetry.
The data help to revise the speciation of uranium(VI) species under seawater conditions. may occur through the formation of uranium mineral phases. The high pH conditions of grout material, pH ~12, limits the solubility of uranium by forming uranyl-oxides, -hydroxides and uranate salts (Serne et al.
a; Serne et al. b; Serne et al. ; Serne et al. The pH was determined asand the uranium concentration was mmol l −1. In the Königstein mine, uranium was directly leached underground with diluted sulfuric acid.
Therefore, the resulting mine water is very acidic having a pH ofand only sulfate is present as major by: Uranium recovery facilities that operated in the s and 70s used an ammonia precipitation process producing ammonium diuranate (ADU) dried (calcined) at high temperatures (typically oF) Characterization by X Ray Diffraction (XRF) and in vitro lung fluid solubility studies performed on those products indicated they were.
Speciation of uranium in environmental relevant compartments* Gert Bernhard1 Abstract In the past, the chemistry of uranium was focused on its mining and milling for production of high pure uranium compounds as initial matter of reactor fuel elements for energy production and breeding of plutonium for weapons production.
Uranium solubility is also reduced in the presence of dissolved V by complexation with vanadate to form the very low solubility mineral carnotite, which is often found as a cementing phase in uraniferous sandstone. In most natural water U is present at concentrations between and 10 µg l-1 (Hem ), although concentrationsFile Size: KB.
The Aqueous Solubility and Speciation Analysis for Uranium, Neptunium and Selenium by the Geochemical Code(EQ3/6) Seiji TAKEDA, Shigeki SHIMA, Hideo KIMURA and Hideo MATSUZURU Department of Environmental Safety Research Tokai Research Establishment Japan Atomic Energy Research Institute Tokai-mura, Naka-gun, Ibaraki-ken (Received October 2, ).
Geochemical Modeling of Solubility and Speciation of Uranium, Neptunium, and Plutonium (3) Document Identifier (including Revision No.): MOD Cited by: 3.
Fig. 31 Uranium Solubility vs. pH 24 Fig. Uranium Speciation at pH = 25 Fig. Uranium Speciation at pH = 25 Fig. pH Drift vs. Time for Closed Batch Samples 31 Fig. Equipment Setup for Vacuum Extraction Method 36 Fig. Evaporation vs. Extraction Time. Uranium solubility in molal NaCl solutions in equilibrium with metaschoepite or Na 2 U 2 O 7 H 2 O(cr) at K plotted as a function of pH.
(a) Uranium solubility calculated with the thermodynamic model used in this study, compared to the solubility data of Altmaier et al.
(b) Distribution of species for the simulation in (a Cited by: 8.A modelling exercise on the importance o ternary alkaline earth carbonate species o uranium(VI) in the inorganic speciation o natural waters Thomas Vercoutera,*, Pascal E.
Reillera, Eric Ansoborlo b, Laureline Févrierc, Rodolphe Gilbin c, Claire Lomenech d, Violaine Philippinie a CEA, DEN, DANS, DPC, SEARS, LANIE, F Gif-sur-Yvette Cedex, France.
Cited by: Uranium is precipitated as species of β-UO 2 (OH) 2 at a neutral pH. This agrees with the results of precipitation experiments. This agrees with the results of precipitation experiments. The aqueous phases having negative charge such as UO 2 (OH) 3 −, (UO 2) 2 CO 3 (OH) 3 −, and UO 2 (CO 3) 3 4− are dominant species at a high pH.