Electromigration of Carrier-free Radionuclides

Rösch, Frank; Milanov, M.; Hung, Tran Kim; Ludwig, Rainer; Buklanov, G. V.; Khalkin, V.A.

doi:10.1524/ract.1987.42.1.43

Cited by 19 publications

(18 citation statements)

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13]: curve in equilibrium with freshly precipitated green amorphous NPO2OH is confirmed to be identical to the results of Lierse et al [1], However, after some days, the amorphous NPO2OH is aged into a greywhite precipitate, which results in a solubility decrease from the upper to the lower curve (Fig. 2).…”

Section: Resultssupporting

confidence: 52%

“…In carbonate-free Solution with OH" as the only complexing ion, solubility of Np(V) is determined by the solubility product of Np020H(s) and by the concentration of the hydroxo complexes NPO2OH and Np02(0H)2 [1][2][3][4][5][6][7][8][9][10][11][12][13]. In spite of the large number of publications [1, 5 -13], current knowledge on solubility product and hydrolysis constants is not at all satisfactory.…”

Section: Introductionmentioning

confidence: 99%

“…However, Kraus evaluated the first hydrolysis constant by Potentiometrie titration without accounting for the formation of the anionic complex Np02(0H)J. Moskvin [12] calculated ßi from only one solubility value at pH = 8.6, assuming Np(V) to be totally hydrolyzed as NPO2OH. Extremely different hydrolysis constants have been obtained from solubility experiments of Lierse et al [1] and Nakayama et al [5] and from electrophoresis studies of Nagasaki et al [6] and Rösch et al [7].…”

Section: Introductionmentioning

confidence: 99%

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Solubility and Hydrolysis Behaviour of Neptunium(V)

Neck¹,

Kim²,

1992

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The hydrolysis behaviour of the NpOi ion has been investigated at 25 by solubility experiments in the pH ränge 7 to 14 in 0.1 M. 1.0 M and 3.0 M NaC104 solutions under pure Ar atmosphere. By measuring the time dependent equiiibrium concentration of Np(V), the chemical State of Np(V) hydroxide precipitatesin each Solution isconfirmed. In 0.1 M NaClO« the precipitate remains amorphous over several months, while in 1.0 M NaClOi the precipitate changes from an amorphous to a more stable aged State within a relatively short time. In 3.0 M NaCiOt the aged modification of NPO2OH is formed from the beginning. Applying specific ion interaction theory (SIT), the thermodynamic constants at 1 = 0 are found to be: log/r,p= -8.76±0.05 for amorphous Np020H(s). logA:,p=-9.44±0.10 for aged Np020H(s), log/?i=2.7±0.2 for the hydrolysis species NpO^OH and iog^2 = 4.35±0.15 for Np02(0H)2".

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Section: Resultssupporting

confidence: 52%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Solubility and Hydrolysis Behaviour of Neptunium(V)

Neck¹,

Kim²,

1992

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“…As both the glass surface and the quantitative composition of colloid microcontaminations may vary from experiment to experiment, their influence on the results of measurements will be different in different series of experiments. In our opinion, this accounts for spread in the experimental data for astatine, which is much larger than for other univalent cations, in particular, for Νρθ£ and Tl + [21,22], Influence of microquentities of elements or their compounds on the At(0) + mobility is illustrated by our results concerning the astatine mobility in background electrolyte solutions containing, apart from persulphate, Ag + 1CT 4 mole Γ 1 . In these solutions practically all astatine remains at the introduction place, its greater part being adsorbed on electromigration tube glass.…”

Section: (3)mentioning

confidence: 53%

Investigation of Astatine Cation Electromigration

et al. 1989

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Electromigration of astatine ( 210 ' 2 " At) has been investigated in aqueous solutions of 0.25 mole I" 1 H(Na)C10"+5 • 10" 3 mole Γ 1 K 2 Cr 2 0, orNa 2 S 2 0, at 25°C, 0.7 < pH < 10.4. Like K 2 Cr 2 0,, Na 2 S 2 0" seems to oxidize astatine only to At(0) + , i. e. to an univalent cation, probably being protonized hypoastatine acid (H 2 0) n At + . The literature data on oxidation of astatine by Na, S 2 0 8 to At 3+ (AtO + ) were not confirmed. The mean mobility of the At(©) + cation is well described by the empiric equation _ = "At(Q) + (1 + *" dp ·«"'+)-(1+6 pH) where = 7.6(3.0)· 10" 5 molel" 1 is the deprotonation constant of (H 2 0) n At + , δ =0.18; "ΑΙ(Θ) + =+3.80(5) Χ ΙΟ" 4 cm 2 V"' s" 1 . In solutions of K 2 Cr 2 0 7 with pH > 1.7 and in solutions without oxidation agents At(0) + is unstable and is converted to a neutral form, probably, At 0 .

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“…[5]. In the field of hydrolysis equilibria the investigation of the formation of [Bi(OH) n ] 3 ~n (n = 1,2,3,4) and of [Np0 2 (0H)" J 1 "" (« = 1,2) has been described [6,7]. 249 Cf.…”

Section: Electromigration Methodsmentioning

confidence: 99%