Separation of yttrium from strontium in the aqueous phase of the water/nitrobenzene extraction system

A rapid separation for carrier-free ⁹⁰Y in the aqueous phase of the water/nitrobenzene extraction system from an ⁹⁰Y/⁹⁰Sr generator was proposed. After two-stage extraction separation, chemical yield of ⁹⁰Y in the final aqueous phase was roughly 80%, while ⁹⁰Sr radionuclide impurity in this phase containing carrier-free ⁹⁰Y was 10^-6%.     

Separation of microamounts of yttrium from strontium by using nitrobenzene solution of sodium dicarbollylcobaltate in the presence of 18-crown-6

A rapid extraction separation of trace amounts of yttrium from strontium with a nitrobenzene solution of sodium dicarbollylcobaltate (NaDCC) and 18-crown-6 in the presence of tetrasodium salt of ethylenediamine-N,N,N",N"- tetraacetic acid (Na₄L) in the aqueous phase was developed. The separation factor a(Sr/Y) was substantially higher than 10⁶. This water-nitrobenzene extraction system can be applied for efficient separation of carrier-free ⁹⁰Y from ⁹⁰Sr/⁹⁰Y generator.     

Separation of microamounts of yttrium from strontium by using sodium dicarbollylcobaltate, Slovafol 909 and ethylenediamine - N, N, N', N'-tetraacetic acid in the water - nitrobenzene extraction system

Summary A rapid extraction separation of trace amounts of yttrium from strontium by a nitrobenzene solution of sodium dicarbollylcobaltate (NaDCC) in the presence of p-nonylphenylnonaethylene glycol (Slovafol 909) and tetrasodium salt of ethylenediamine - N,N,N',N' - tetraacetic acid (Na₄L) in the aqueous phase was developed. The separation factor a(Sr/Y) was substantially higher than 10⁵. This water-nitrobenzene extraction system can be applied for the efficient separation of carrier-free ⁹⁰Y from ⁹⁰Y/⁹⁰Sr generator.     

Separation of radioactive yttrium from strontium by means of mono-octyl anilinobenzylphosphonate

Zusammenfassung Die Trennung des radioaktiven⁹⁰Y von Sr mit Monooktyl-anilinobenzyl-phosphonat wurde beschrieben. Y geht aus 0,1- bis 0,01-m Salzsäure quantitativ in die organische Phase über, während Sr in der wäßrigen Phase bleibt. Die Trennung läßt sich entweder aus verd. Yttriumlösung oder bei Vorliegen der trägerfreien Form durchführen. Die Sr-Menge hat keinen Einfluß. Der Trennungsfaktor beträgt 10⁶. Die Reinheit des abgetrennten⁹⁰Y wurde an Hand seiner Abklingkurve geprüft.

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Part of the thesis submitted byN. Vujii in partial fulfilment of the requirements for the degree of Master of Science in Chemistry (M. Sc.) at the Faculty of Pharmacy and Biochemistry, University of Zagreb.     

Self-organization of water in lithium/nitrobenzene system

The effect of lithium ion on the ordering of water in water-saturated nitrobenzene has been probed by 2H NMR, diffusion ordered spectroscopy and neutron scattering. It was shown that increased water concentration in LiClO4/wet nitrobenzene results in the formation of a metastable solvatomer with mixed water and nitrobenzene character, Li+(W/NB). This species is shown to decay over hours to two solvatomers, one dominated by nitrobenzene Li+(NB) and the other dominated by water Li+(W). To confirm the assignment of these solvation states, diffusion ordered deuterium NMR spectroscopy has been used to elucidate the hydrodynamic radii of these solvatomers. Neutron scattering yields vibrational spectroscopy information that shows how addition of lithium to the nitrobenzene/water system results in relatively slow self-organization of the water environment (hours).     

Stability of the valinomycin - strontium complex in water saturated nitrobenzene

Summary From extraction experiments and<span style='font-size:12.0pt;font-family:Symbol; mso-bidi-font-family:Symbol'>g-activity measurements, the extraction constant corresponding to the equilibrium Ba²⁺(aq)+SrL²⁺(nb)?BaL²⁺(nb)+Sr²⁺(aq) taking place in the two-phase water-nitrobenzene system (L= valinomycin; aq= aqueous phase,</o:p>nb= nitrobenzene phase) was evaluated as logK_ex(Ba²⁺, SrL²⁺)=1.3. Furthermore, the stability constant of the valinomycin-strontium complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: logb_nb(SrL²⁺)=5.4.     

Solvent extraction of strontium picrate from water into nitrobenzene in the presence of benzo-15-crown-5

From extraction experiments with 85Sr as a tracer, the extraction constant corresponding to the equilibrium Sr²⁺(aq) + 2A^- (aq) + 2L (nb) Û SrL₂ ^,2+ (nb) 2A^- (nb) in the two-phase water-nitrobenzene system (A^- = picrate, L = benzo-15-crown-5; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K _ex     

Mathematical modeling of separation of microamounts of strontium from yttrium in the two-phase water-nitrobenzene extraction system

A rapid extraction separation of microamounts of Sr²⁺ from Y³⁺ using HCl, benzo-15-crown-5 (B15C5) and hydrogen dicarbollylcobaltate (H⁺B^-) in the two-phase water-nitrobenzene system was developed. The reached separation factor α(Sr/Y) was higher than 10⁵.     

Extraction of microamounts of yttrium from water into nitrobenzene using hydrogen dicarbollylcobaltate in the presence of 15-crown-5

Summary Extraction of microamounts of yttrium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B^-) in the presence of 15-crown-5 (15C5,L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, HL_2,⁺, YL³⁺, YL_2,³⁺and YH_-1L_2,²⁺are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Separation of microamounts of strontium from calcium in the two-phase water-nitrobenzene extraction system

Summary A rapid separation of Sr²⁺from Ca²⁺using HCl, 15-crown-5 (15C5) and hydrogen dicarbollylcobaltate (H⁺B^-) in the two-phase water-nitrobenzene extraction system was developed. The reached separation factora(Sr/Ca) was approximately 10.^3,6     

Transfer of cesium ion from the aqueous phase into the mixed organic phase of a two-phase water/nitrobenzene-carbon tetrachloride extraction system

Standard Gibbs energies of transfer of cesium ion from water to nitrobenzene and nitrobenzene-carbon tetrachloride mixture have been evaluated from electrochemical measurements. From the results the conclusion can be drawn that with increasing dielectric permitivity of organic mixed solvents the value of the Gibbs transfer energy of Cs⁺ ion decreases.     

Charge transfer across the water/nitrobenzene interface by three-electrode system

A droplet of aqueous solution containing a certain molar ratio of redox couple is first attached onto a platinum electrode surface, then the resulting drop electrode is immersed into the organic solution containing very hydrophobic electrolyte. Combined with reference and counter electrodes, a classical three-electrode system has been constructed. Ion transfer (IT) and electron transfer (ET) are investigated systematically using three-electrode voltammetry. Potassium ion transfer and electron transfer between potassium ferricyanide in the aqueous phase and ferrocene in nitrobenzene are observed with potassium ferricyanide/potassium ferrocyanide as the redox couple. Meanwhile, the transfer reactions of lithium, sodium, potassium, proton and ammonium ions are obtained with ferric sulfate/ferrous sulfate as the redox couple. The formal transfer potentials and the standard Gibbs transfer energy of these ions are evaluated and consistent with the results obtained by a four-electrode system and other methods.     

Extraction of lead from water into nitrobenzene by using strontium dicarbollylcobaltate in the presence of benzo-15-crown-5

Summary From extraction experiments andg-activity measurements, the extraction constant corresponding to the equilibrium Pb²⁺(aq)+SrL(nb)?PbL(nb)+Sr²⁺(aq)taking place in the two-phase water-nitrobenzene system (L = benzo-15-crown-5; aq = aqueous phase, nb = nitrobenzene phase) was evaluated aslog K_ex(Pb²⁺,SrL)=0.1±0.1. Further, the stability constant of the benzo-15-crown-5-lead complex in nitrobenzene saturated with water was calculated for a temperature of25 °C:log b_nb(PbL)=13.2±0.1.     

The phase transfer mechanism of 18-molybdophosphate anion at the water/nitrobenzene interface

The phase transfer mechanism of 18-molybdophosphate anion at the water/nitrobenzene interface has been investigated by chronopotentiometry with cyclic linear current-scanning (CLC) and cyclic voltammetry (CV). The transfer species is 18-molybdophosphtae anion with a charge number of 4, H₂[P₂Mo₁₈O₆₂]^4-. The transfer process is controlled by diffusion at a slow polarization rate and considerably influenced by pH of the aqueous phase. The stable forms and pH range of the heteropoly anion in the aqueous solution can be directly confirmed through voltammetric behavior. The theoretical analysis of the relationship between the transfer potential and solution pH is identical to the experimental results. The linear concentration relationship with the transfer peak current is suggested to be used in the determination of heteropoly acids (salts).     

冠醚-离子液体体系对水相中锶离子的萃取研究

本文研究了以一系列离子液体作为介质时,萃取剂二环己基18冠6（DCH18C6）对水相中Sr^2＋的萃取行为．研究结果表明,DCH18C6／离子液体体系对Sr^2＋的萃取性能优于相应的DCH18C6／JE辛醇萃取体系,一定条件下其萃取Sr^2＋的分配比可达10^3量级．同时,体系对Sr^2＋的萃取性能随着离子液体的结构不同而有所差别．在离子液体萃取体系中,随着水相初始硝酸浓度的增加,对Sr^2＋的萃取性能下降．水相中Na^＋、K^＋等离子的存在也会对体系萃取Sr^2＋产生直接影响．本文还验证了离子液体体系萃取Sr^2＋的机理,即以阳离子交换机理为主实现对Sr^2＋的萃取．     

Investigation on the extraction of strontium ions from aqueous phase using crown ether-ionic liquid systems

The extraction of strontium ions using DCH18C6 as the extractant and various ionic liquids (ILs) as solvents has been investigated. The distribution ratio of Sr²⁺ can reach as high as 10³ under certain conditions, much larger than that in DCH18C6/n-octanol system. The extraction capacity depends greatly on the structure of ionic liquids. In IIs-based extraction systems, the extraction efficiency of strontium ions is reduced by increasing the concentration of nitric acid and can also be influenced directly by the presence of Na⁺ and K⁺ in the aqueous phase. It is confirmed that the extraction proceeds mainly via a cation-exchange mechanism.     

Solvent extraction of sodium from water into nitrobenzene by using strontium dicarbollylcobaltate in the presence of benzo-15-crown-5

Summary From extraction experiments andg-activity measurements, the extraction constant corresponding to the 2Na⁺(aq)+SrL(nb)?2NaL⁺(nb)+Sr²⁺(aq) equilibrium taking place in the two-phase water-nitrobenzene system (L=benzo-15-crown-5; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as log K_ex(2Na⁺,SrL)=1.0±0.1. Further, the stability constant of the benzo-15-crown-5-sodium complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log b_nb(NaL⁺)=7.8±0.1.     

Separation of strontium and yttrium in nitric acid solutions using zirconium titanium phosphate and Dowex exchangers

Sulfonated ion irradiated (H⁺ and He²⁺) PEEK films were synthesized with a range of cross-linking density and a variety of sulfonation degrees. Batch adsorption experiments were carried out at an initial pH of 6.0 ± 0.2, initial concentrations of Pb²⁺ and ¹³⁷Cs ions of 10.0 mg L⁻¹ and 5500 Bq L⁻¹, respectively. The maximum adsorption capacity was 60 mg g⁻¹ for Pb²⁺, and the distribution coefficient reached 6200 cm³ g⁻¹ for ¹³⁷Cs. The results indicated that sulfonation could be used to recycle low cross-linked PEEK and prepare efficient adsorbents to remove toxic Pb²⁺ and ¹³⁷Cs from polluted aqueous solutions.

     

Membraneless dialysis of strontium in aqueous liquid-liquid milk-pectin system

Binding of added strontium by milk proteins under native conditions was investigated using pectin of various degrees of esterification. The partition of strontium, as well as cesium and europium, in aqueous two-phase milk-pectin system, is discussed in terms of membraneless dialysis and described by Donnan equilibria, and compared with the distribution between cation exchanger and milk, artificial milk serum, or pectin solutions. When going from pectin with a degree of esterification D.E.=93.2 to 61.4, the distribution of strontium decreases for about 40% in favor of pectin phase and this was explained by a relatively lower degree of dissociation of free carboxyle groups of pectin. The low-molecular fraction of added strontium in milk was assessed from Dowex 50×8 sorption data to be 31%, and that of cesium and europium 58% and 40%, respectively. However, distribution ratio of strontium and europium in milk/pectin system is much higher than it would correspond to the ion exchanger adsorption data.     

Applications of the dicarbollylcobaltate(III) anion in the water/nitrobenzene extraction system

The fundamental properties of the polyhedral sandwich dicarbollylcobaltate(III) anion {[pi-(3)-1,2-B(9)C(2)H(11)](2)Co(III)}(-) are given, together with results for extraction of alkali-metal, alkaline-earth metal and some other cations (e.g., H(+), Pb(2+), Pd(2+) and Ce(3+)) into nitrobenzene and corresponding analytical applications. Considerable attention is paid to charge-transfer through the water-nitrobenzene interface in the presence of this hydrophobic anion.