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Abstract  

Transport of uranyl ions through liquid membranes consisting of tri-n-butylphosphate (TBP) in kerosene oil supported in Celgard 2400 polypropylene microporous film has been studied. Various parameters, such as the effect of nitric acid concentration in the feed solution, TBP concentration in the organic membrane phase, stripping agent concentration and temperature on the flux of uranium across the liquid membrane, have been investigated. The results obtained have been used to elucidate the mechanism of uranium transport and stoichiometry of the diffusing species.

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Summary  

A systematic study on the extraction of U(VI) from nitric acid medium by tri-n-butylphosphate (TBP) dissolved in a non-traditional diluent namely 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6) ionic liquid (IL) is reported. The results are compared with those obtained using TBP/n-dodecane (DD). The distribution ratio for the extraction of U(VI) from nitric acid by 1.1M TBP/bmimPF6 increases with increasing nitric acid concentration. The U(VI) distribution ratios are comparable in the nitric acid concentration range of 0.01M to 4M, to the ratios measured using 1.1M TBP/DD. In contrast to the extraction behavior of TBP/DD, the D values continued to increase with the increase in the concentration of nitric acid above 4.0M. The stoichiometry of uranyl solvate extracted by 1.1M TBP/IL is similar to that of TBP/DD system, wherein two molecules of TBP are associated with one molecule of uranyl nitrate in the organic phase. Ionic liquid alone also extracts uranium from nitric acid, albeit to a small extent. The exothermic enthalpy accompanying the extraction of U(VI) in TBP/bmimPF6 decreases with increasing nitric acid and with TBP concentrations.

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Abstract  

Radioanalytical techniques are used in this work to investigate the extraction behaviour with TBP of rhodium (III) chloride solutions to which a large excess of iodide is added. Extraction yields and distribution coefficients are determined as a function of HClO4 or H2SO4 content in the aqueous phase. Rhodium-stripping from the organic phase with ammonia solutions is also tested.

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Abstract  

Extraction of europium(III) from nitric acid medium by a solution of tri-n-butylphosphate (TBP) and n-octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) in the room temperature ionic liquid, 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (amimNTf2 where a = butyl or hexyl or octyl), was studied. The distribution ratio of (152+154)Eu(III) in TBP-CMPO/bmimNTf2 was measured as a function of various parameters such as the concentrations of nitric acid, CMPO and NaNO3. Remarkably large distribution ratios were observed for the extraction of europium(III) when bmimNTf2 acted as diluent. The stoichiometry of metal-solvate in organic phase was determined by the slope analysis of extraction data.

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Abstract  

Decomposition yields of tri-n-butylphosphate in methanol solutions saturated with Ar or N2O were determined. On the basis of difference between yields in Ar and N2O saturated solutions the rate constant k/e s +TBP/=5.0×106 dm3.mol–1.s–1 was calculated.

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Abstract  

The solvent extraction of molybdenum(VI) from sulphuric acid solutions with di-(2-ethylhexyl)-phosphoric acid (HDEHP) and monododecylphosphoric acid (HDDP) in n-heptane has been studied (a) as a function of the concentration of sulphuric acid, molybdenum and the extractant; (b) in the presence of copper and zinc in the aqueous phase and (c) in the presence of tri-n-butylphosphate (TBP) in the organic phase. The distribution of the sulphuric acid between aqueous and organic phase has also been studied.

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Abstract  

Various double emulsion systems with liquid membranes containing tri-n-octylphosphine oxide /TOPO/, tri-n-butylphosphate /TBP/, KELEX 100® and di-2-ethylhexylphosphoric acid /DEHPA/, as carriers for uranium/VI/ pertraction, were studied. The conditions were found at which the systems are most efficient, comparing with solvent extraction. The use of DEHPA as a membrane carrier with solutions of H2SO4 and H3PO4 encapsulated in the membrane was substanfiated.

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Abstract  

ESR spectroscopy at 77 K has been used for the investigation of radicals formed in the low-temperature X-radiolysis of tri-n-butylphosphate /TBP/, di-n-butylphosphate /DBP/, di /2-ethylhexyl/phosphoric acid /DEHPA/, tri-p-tolylphosphate /TTP/, di-n-butyl-n-butylphosphonate /DBBPN/. Besides the phosphate radicals also hydrogen atom stabilization in the matrix has been observed. In the presence of oxygen peroxy radicals occur as well. The structure of the radicals and reaction mechanisms are discussed.

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Abstract  

The separation of lanthanum from calcium and a number of radioisotopes of other elements by extraction with alkylphosphoric acids and tri-n-butylphosphate has been studied. A quantitative method has been developed for the separation of a lanthanum tracer from neutron-irradiated preparations on a calcium carrier, obtained from the steel-making process. This method improves the detectability of140La (from 5·10−7 to 10−10 g of La) by γ-ray spectrometry with a scintillation counter, and enables semiquantitative determination of lanthanum with a liquid GM tube, the error involved being about 100% for La contents >10−8 g, and about 30% for La contents >10−7 g.

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Trennung von Spaltprodukten durch extraktionschromatographie

I. Bestimmung der verteilungskoeffizienten

Journal of Radioanalytical and Nuclear Chemistry
Authors: R. Denig, N. Trautmann, and G. Herrmann

Abstract  

The possibilities for the separation of a complex fission product mixture by extraction chromatography have been investigated. Here the partition coefficients between three solvents and hydrochloric acid are reported for the following elements: Zn(II), Ge(IV), As(III), As(V), Se(IV), Zr(IV), Nb(V), Mo(VI), Tc(IV) Ru(III), Ru(IV), Rh(III), Ag(I), Cd(II), In(III), Sn(IV), Sb(III), Sb(V), Te(IV), I(oxidized), Cs(I), Ce(III), Tb(III), Tm(III), Ac(III), Th(IV), Pa(V), U(VI), Np(IV), Np(VI). As solvents tri-n-butylphosphate (TBP), tri-n-octylamine (TOA) and di-(2-ethylhexyl)-orthophosphoric acid (HDEHP) have been used. The partition coefficients have been measured by batch-experiments in which the solvents were adsorbed on polytrifluoromonochloroethylene powder.

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