Ionic Species of Pentavalent Protactinium in Hydrochloric Acid Solutions

Scherff, H.L.; Herrmann, G.

doi:10.1524/ract.1966.6.2.53

Cited by 21 publications

(14 citation statements)

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“…Fig. 2 suggests the involvement of ~1-2 DIBC molecules during Pa extraction process through the formation of ion-paired complex [28]. Similar solvation has been observed during nitric acid extraction.…”

Section: Acid Uptake Behavior Of Dibcsupporting

confidence: 69%

“…1). Similar observations have been reported during the extraction of HCl by DIBC [28]. The acid uptake constant, K H , was calculated from the intercept value as 0.01.…”

Section: Acid Uptake Behavior Of Dibcsupporting

confidence: 64%

“…Similar solvation has been observed during nitric acid extraction. Therefore, the nitric acid is extracted as an ion pair of the type [H(DIBC) 1-2 ] + · [NO 3 -] [28]. The activity of this species increases with increased nitric acid concentration and that of free DIBC decreases.…”

Section: Acid Uptake Behavior Of Dibcmentioning

confidence: 99%

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Solvent extraction studies of protactinium for its recovery from short-cooled spent fuel and high-level waste solutions in thorium fuel cycle using diisobutyl carbinol (DIBC) as extractant

Kumari

Pathak

Prabhu

et al. 2012

Desalination and Water Treatment

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A B S T R AC TConditions have been optimized for selective removal of protactinium by solvent extraction from short-cooled spent fuel dissolver solution and from high-level waste solution under simulated conditions employing diisobutyl carbinol (DIBC) as extractant. These studies include: effect of acidity, extractant and thorium concentration on the extraction behavior of protactinium. Selectivity of the extractant for protactinium has been investigated with respect to U, Pu, Th, and the fi ssion/activation products. These studies suggest that 40% DIBC (~2.02 M) solution in n-dodecane can be employed for the recovery of protactinium from short-cooled spent fuel dissolver solution and from high-level waste solutions. Extraction of Pa increased with aqueous phase acidity due to the formation of protonated species of DIBC, [H(DIBC) 1−2 ] + and anionic Pa(OH) 2 (NO 3 ) 4 ] -species. There was an enhancement in Pa extraction at lower acidities 4 M HNO 3 ) with increased Th concentration (up to 200 g/l) beyond which a decrease was observed. At 200 g/l Th in 4 M HNO 3 , the separation factor (SF) values of Pa over U and Th are ~100, >10 5 , respectively. DIBC displays good fi ssion/activation product decontamination under the c onditions of these studies.

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Section: Acid Uptake Behavior Of Dibcsupporting

confidence: 69%

“…1). Similar observations have been reported during the extraction of HCl by DIBC [28]. The acid uptake constant, K H , was calculated from the intercept value as 0.01.…”

Section: Acid Uptake Behavior Of Dibcsupporting

confidence: 64%

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Solvent extraction studies of protactinium for its recovery from short-cooled spent fuel and high-level waste solutions in thorium fuel cycle using diisobutyl carbinol (DIBC) as extractant

Kumari

Pathak

Prabhu

et al. 2012

Desalination and Water Treatment

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“…Although the mutual solubility of the two phases has been negligible and the metal ion is at tracer level concentration, the extractant solutions as well as protactinium solutions are far from ideal, several other interactions having not been taken into account, and hence the nature of the species extracted, as determined by slope-analysis, is an approximation. Since the various protactinium species [14] in aqueous HCl solutions (2-8M) are in a State of dynamic equilibrium with the equüibrium being rapidly estabhshed [18], during extraction the equilibrium is shifted and the system behaves as if the entire protactinium in the aqueous phase is in the form of PaO^"" /Pa(OH)r [19]. The species extracted thus appear to be PaOCla • 3 DPSO, PaOCls • 3 DOSO and PaOClj • 2 TBP [20], In the cases of mixtures of sulphoxides or of sulphoxide and TBP, the slope of the linear plots of logDlog [extractant] for one component progressively decreases with increase in the concentration of the second component, which Substitutes the first in the extracted complex, and all these mixtures of neutral donors exhibit synergism.…”

Section: Influence Of Extractant Concentrationmentioning

confidence: 99%

Liquid-liquid Extraction of Pa(V) and U(VI) by Dialkyl Sulphoxides

1986

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Distribution /Extraction /Sulphoxides/Uraniumf VI) /Protactinium(V) AbstiactThe liquid-liquid extraction of protactinium(V) from HCl solutions by dipentyl and dioctyl sulphoxides (DPSO and DOSO, respectively), tributyl phosphate (TBP) and theii mixtures in diluents over a wide ränge of conditions has been studied. The species extracted appear to be PaOO, • 3 DPSO, PaOCl, • 3 DOSO and PaOClj -2 TBP. The mixtures of extractants exhibit synergism. The extraction of Pa(V) increases roughly linearly with decrease in the dielectric constant of the diluent. In the extraction of uranium(VI) from HCl solutions by a series of sulphoxides (R, SO) from dipentyl to didecyl, the extracted species appear to be of the type UO, O, • 3 R, SO and/or UO, Cl, • HO • 3 R, SO. Dipentyl and dioctyl sulphoxides are shown to be better extractants. The extraction efficiency of the sulphoxides follows the order: dioctyl > dipentyl > diheptyl > dinonyl > dihexyl > didecyl sulphoxide at any aqueous acidity of the ränge studied. A comparative study of the extraction of zirconium(IV), thorium(IV), protactinium(V), and uranium(VI) with dipentyl sulphoxide (DPSO) shows that the metals can be separated from one another under controlled conditions of aqueous phase acidity.

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“…It was found [2] The dose similarity of the chemical behaviour of dement 105 to that of Pa and Nb has motivated us to conduct additional experiments in which diisobutylcarbinol (DIBC), a secondary alcohol, was used as the extractant. This extractant has been shown repeatedly to be very seledive for Pa [5,6,7], and well suited to perform Pa-Nb separations [6,7]. In this paper, we report on the development of reversed-phase Chromatographie separations of Pa and Nb in the system HBr, HCl/DIBC, and on the appUcation of this scheme to further assess the halide-complexation and extraction behaviour of Ha.…”

Section: Introductionmentioning

confidence: 99%

Chemical Properties of Element 105 in Aqueous Solution: Extractions into Diisobutylcarbinol

et al. 1992

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Element 105 / Chemical properties / Halide complex formation / Extraction into a secondary alcohol SummaryStudies of the extraction of element 105 into diisobutylcarbinol (DIBC) from aqueous HBr and HCl solutions wcre performed on "^Ha and "^Ha produced in the "'Bk("0,5n) and reactions at a beam energy of 99 MeV. The Ha isotopes were detected by measuring the fission and a activities associated with their decay and the a-decays of their daughters, 4-s and 6-s ^''Lr. Complete extraction-elution cycles were performed on a one-minute time scale by the computer-controlled liquid chromatography apparatus, ARCA II, using reversed-phase micro-chromatographic columns incorporating DIBC on an inert support. Stimulated by the previously observed similarity of the aqueous-phase chemistry of element 105 to that of niobium and protactinium, the extraction, from concentrated HBr, was followed by the elution of a Nb fraction in 6 M HCl/ 0.0002 M HF, and a Pa fraction in 0.5 M HCl. The number of 262,263j^^ dccays observed in the Nb fraction indicated that less than 45% of the Ha was extracted into DIBC from concentrated HBr. This was confirmed in a series of experiments in which, after the extraction, the DIBC along with all extracted species was stripped from the columns with acetone. It is concluded that, in the present chemical system, the extraction behaviour of element 105 is closer to that of niobium than to that of protactinium. The decreasing extractability from HBr (Pa > Nb > Ha) is likely to be due to an increasing tendency of these Clements to form non-extractable polynegative complex species in concentrated HBr in the sequence Pa < Nb < Ha.

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Ionic Species of Pentavalent Protactinium in Hydrochloric Acid Solutions

Cited by 21 publications

References 0 publications

Solvent extraction studies of protactinium for its recovery from short-cooled spent fuel and high-level waste solutions in thorium fuel cycle using diisobutyl carbinol (DIBC) as extractant

Solvent extraction studies of protactinium for its recovery from short-cooled spent fuel and high-level waste solutions in thorium fuel cycle using diisobutyl carbinol (DIBC) as extractant

Liquid-liquid Extraction of Pa(V) and U(VI) by Dialkyl Sulphoxides

Chemical Properties of Element 105 in Aqueous Solution: Extractions into Diisobutylcarbinol

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