Studies on the Hydrolysis of Metal Ions. X. The Hydrolysis of the Uranyl Ion, UO22.

Ahrland, Sten; Hietanen, Sirkka; Sillén, Lars Gunnar; Sørensen, Nils Andreas

doi:10.3891/acta.chem.scand.08-1907

Cited by 53 publications

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“…Any proposed structure of a (3,4,4) species must include bridging sulfate molecules (for example, see the structure given in Grenthe and Lagerman [1]) and, as such, cannot be supported by the EXAFS data of Moll et al [15]. Proposed structures for the ternary (2,2,2), (3,4,3) and (5,8,4) species have been given previously [1,15]. Similarly, the tetrameric species has the proposed structure illustrated in Fig.…”

Section: Discussionmentioning

confidence: 89%

“…Four complexes were proposed, namely (UO 2 ) 2 (OH) 2 2+ , (UO 2 ) 3 (OH) 4 2+ , (UO 2 ) 4 (OH) 6 2+ and (UO 2 ) 5 (OH) 8 2+ . The results from the study indicated that uranyl hydrolysis in a sulfate medium produced the same hydrolytic species that had been found earlier in a perchlorate medium [4], except that the hydrolysis occurred about one pH unit higher in the sulfate medium. Petersen [3] attributed this pH shift to relatively strong complex formation between uranyl and sulfate ions in the 1.5 mol dm −3 Na 2 SO 4 medium.…”

Section: Introductionmentioning

confidence: 77%

“…It is possible, however, to determine the stability constants for reactions (5), as defined by equation (6), (6) provided that the activity coefficients for the reactants and products remain relatively constant throughout the fairly large changes in the composition of the test solutions [1]. Following the methodology described by Grenthe and Lagerman [1], stability constants have been determined for the ternary species, (2,2,2), (3,4,3), (4,7,4) and (5,8,4). The calculated stability constants are listed in Table 4.…”

Section: Discussionmentioning

confidence: 99%

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The hydrolysis of uranium(VI) in sulfate media

Comarmond¹,

Brown²

2000

Radiochimica Acta

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Potentiometry / Uranium(VI) / Sulfate / Hydroxide / Stability constants / Ternary complexesSummary. The hydrolysis of uranium(VI) has been investigated in 0.10 and 1.0 mol dm −3 Na 2 SO 4 using the potentiometric titration technique. Analysis of the data indicates the presence of the following uranyl hydrolysis species: (UO 2 ) 2 (OH) 2 2+ , (UO 2 ) 3 (OH) 4 2+ , (UO 2 ) 4 (OH) 7 + and (UO 2 ) 5 (OH) 8 2+ in both media, and additionally, UO 2 OH + and (UO 2 ) 3 (OH) 5 + in the lower ionic strength only. The data were used to calculate stability constants for ternary uranyl hydroxo-sulfate complexes. These constants were found to be in excellent agreement with those found in an earlier study at a higher Na 2 SO 4 concentration (1.5 mol dm −3 ).

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Section: Discussionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 99%

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The hydrolysis of uranium(VI) in sulfate media

Comarmond¹,

Brown²

2000

Radiochimica Acta

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“…The use of Raman spectroscopy to investigate the UO 2 (NO 3 ) 2 /nitric acid system is well established [3, 11-14, 31, 32], and experimental studies have indicated that several solution species exist for uranyl nitrate, including UO 2 (NO 3 ) + [14,[33][34][35][36][37], the neutral complex UO 2 (NO 3 ) 2 [14,37,38], and UO 2 (NO 3 ) 3 − [37,39]. We have measured solutions of spent commercial fuel in variable nitric acid solutions using Raman spectroscopy to probe the UO 2 -NO 3 interaction under fuel reprocessing conditions and identify spectral regions that can be used for the on-line monitoring of uranyl nitrate.…”

Section: Resultsmentioning

confidence: 99%

Spectroscopic monitoring of spent nuclear fuel reprocessing streams: an evaluation of spent fuel solutionsviaRaman, visible, and near-infrared spectroscopy

Bryan¹,

Levitskaia

Johnsen

et al. 2011

Radiochimica Acta

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The potential of using optical spectroscopic techniques, such as Raman and visible/near infrared (Vis/NIR), for on-line process control and special nuclear materials accountability applications at a spent nuclear fuel reprocessing facility was evaluated. The availability of on-line, real-time techniques that directly measure process concentrations of nuclear materials will enhance the performance and proliferation resistance of the solvent extraction processes. Further, on-line monitoring of radiochemical streams will also improve reprocessing plant operation and safety. This paper reviews the current state of development of the spectroscopic on-line monitoring techniques for such solutions. To further examine the applicability of optical spectroscopy for this application, segments of a spent nuclear fuel, with approximate burn-up values of 70 MW d/kg M, were dissolved in concentrated nitric acid and adjusted to varying final concentrations of HNO 3 . The resulting spent fuel solutions were batch-contacted with tributyl phosphate/n-dodecane organic solvent. The feed and equilibrium aqueous and loaded organic solutions were subjected to optical measurements. The obtained spectra showed the presence of quantifiable Raman bands due to NO 3 − and UO 2 2+ and Vis/NIR bands due to multiple species of Pu(IV), Pu(VI), Np(V), the Np(V)-U(VI) cation-cation complex, and Nd(III) in fuel solutions. This result justifies spectroscopic techniques as a promising methodology for monitoring spent fuel processing solutions in real-time. The fuel solution was quantitatively evaluated based on spectroscopic measurements and was compared to inductively coupled plasma-mass spectroscopy analysis and Oak Ridge Isotope Generator (ORIGEN)-based estimates.

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“…Previous investigation by other workers (2,5) has shown that as the pH of uranyl nitrate solutions is raised hydrolysis occurs and polynuclear complexes are formed. At sufficiently high pH's these complexes aggregate and a visible precipitate results.…”

Section: Oomentioning

confidence: 99%

Electron Stains

Zobel

Beer

1961

The Journal of Cell Biology

106

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Chemical studies have been carried out on the interaction of DNA with uranyl salts. The effect of variations in pH, salt concentration, and structural integrity of the DNA on the stoichiometry of the salt-substrate complex have been investigated. At pH 3.5 DNA interacts with uranyl ions in low concentration yielding a substrate metal ion complex with a UO++/P mole ratio of about ~ and having a large association constant. At low pH's (about 2.3) the mole ratio decreases to about 1/~. Destruction of the structural integrity of the DNA by heating in HCHO solutions leads to a similar drop in the amount of metal ion bound. Raising the pH above 3.5 leads to an apparent increase in binding as does increasing the concentration of the salt solution. This additional binding has a lower association constant. Under similar conditions DNA binds about seven times more uranyl ion than bovine serum albumin, indicating useful selectivity in staining for electron microscopy.

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Studies on the Hydrolysis of Metal Ions. X. The Hydrolysis of the Uranyl Ion, UO22.

Cited by 53 publications

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The hydrolysis of uranium(VI) in sulfate media

The hydrolysis of uranium(VI) in sulfate media

Spectroscopic monitoring of spent nuclear fuel reprocessing streams: an evaluation of spent fuel solutionsviaRaman, visible, and near-infrared spectroscopy

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