摘要:

The extraction of tracer Am(III) with macro amounts of Ce(III), Pr(III), Nd(III), Sm(III) and Eu(III) has been studied using Cyanex 272 and Cyanex 301 in heptane. For extraction by Cyanex 272, the average separation factor of Am/Nd was 0.82, while that for Am/Eu was 0.088. However, for the Cyanex 301 extraction, separation factors of 810 for Am/Nd and 840 for Am/Eu were obtained. The separation values are not affected by the concentration of the extractant but decrease as the loading of the lanthanide increases in the organic phase. The hypersensitive absorption spectrum of the complex of Nd with Cyanex 301 in the heptane solvent indicates the formation of a Nd-S bond. The extractions by HDEHP under the same conditions are compared with that of Cyanex 272 and 301.

ISSN:0736-6299    

DOI:10.1080/07366299608918355

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The results of acidimetric titration, infrared spectroscopy and31P-NMR show that dialkylmonothiophosphinic acid, dialkylphosphinic acid and other phosphorus compounds form when Cyanex 301™ is damaged by Y-irradiation. H2SO4appears after a dose of l×l06Gy. The radiolytic stability of Cyanex 301 improves after purification. The results of extraction experiments demonstrate that the extraction selectivity of Cyanex 301 toward Am over the lanthanides decreases after irradiation. The purified Cyanex 301 can still separate tracer amount of Am from tracer amount of Eu till lx 105Gy while the commercial Cyanex 301 can do so only with l×l04Gy.

ISSN:0736-6299    

DOI:10.1080/07366299608918356

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The use of nuclear magnetic resonance (NMR) spectroscopy to elucidate the structure of complexes formed in liquid-liquid extraction is reported. 3IP spectral information provided substantive evidence for the structural difference of the isolated solid complex and the complex in solution. Solvent effect exists for the31P chemical shift of the lanthanum-2-ethylhexyl phenylphosphonate in n-hexane, toluene and tetrahydrofuran, as well as in the extractability of lanthanum from aqueous perchloric acid solution.

ISSN:0736-6299    

DOI:10.1080/07366299608918357

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Organophosphorus acids, including di(2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethyIhexyI phosphonic acid mono 2-ethylhexyl ester (PC88A), and di(2-ethylhexyl) phosphinic acid (P229) form reversed micelles (d=20-100A) or water-in-oil (w/o) microemulsions (d=100-2000 A) in n-heptane when they are saponified with concentrated alkalis, such as NaOH, KOH and NH3H2O. After equilibrating with water or solution containing europium, some extractant and diluent in the saponified organic phase transfers into the aqueous phase, and some water solubilized in the w/o microemulsion returns to the aqueous phase. Dynamic light scattering (DLS) results indicate that aggregates within the range of micelles or microemulsions are formed in the equilibrated aqueous phase. The normal micelle or o/w microemulsion has a non-polar core that solubilizes n-heptane. Therefore, the formation of aqueous aggregates leads to extractant and diluent loss in the extraction procedure. FT-IR spectra also confirm the presence of extractant and diluent in the final aqueous phase. Inorganic salts (NaCl, NaN03or Na2SO4)

ISSN:0736-6299    

DOI:10.1080/07366299608918358

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A new extraction agent, N-pentafluorobenzoyl-N-phenylhydroxylamine (PFBPHA), was synthesized. The solvent extraction of Pr (II), Eu (II) and Yb (II) with PFBPHA has been investigated at an ionic strength of 0.2 and 25 ±1°C It. The acid dissociation constant, KD, and the partition coefficient, KD, of its metal complexes were determined. These results obtained were compared with those of N-benzoyl-N-phenylhydroxy1amine (BPHA) reported previously. The introduction of fluoro group to the C-phenyl ring of BPHA was very effective for increasing not only the Kavalue of PFBPHA but also its KDvalue and the extraction constant, KBX, of its lanthanoid complexes.

ISSN:0736-6299    

DOI:10.1080/07366299608918359

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A thermodynamic model that predicts the extraction of trivalent lanthanide (Pr, Nd) nitrates and water from aqueous solutions by tri-n-butylphosphate (30, 50 and 100 vol%) in dodecane is presented. The Mikulin-Sergievskii-Dannus’ model was used to predict the extraction isotherms of lanthanides (Ln) and water for Ln(N03)-3H30-TBP-dodecane system and Ln(N03)3-NH4N03-H20-TBP-dodecane system. The parameters of the model were used in conjunction with those previously published for nitric acid extraction by TBP, to predict the extraction isotherms of lanthanides and nitric acid for Ln(N03)3-HN03-H20-TBP 100 vol%system The stoichiometric mean activity coefficients of components in the aqueous phase were calculated from experimental data using Mikulin's equation, and those of the components in the organic phase were calculated by Sergievskii-Dannus'equation. A satisfactory description of the distribution of lanthanide nitrate and water is obtained over a wide range of lanthanide concentration in the aqueous phase by taking into account the formation of the following complexes: TBP,TBP H20,(TBP)3Nd(N03)3,(TBP)4Pr(N03)3, (TBP)3-Pr(N03)v It was shown that in Ln(N03)3-HNOrH20-TBP 100 vol% system, it is necessary to consider anacid-complex,(TBP)3-HLn(NO3)4, in order to obtain the best fit of the isotherms to the extraction data.

ISSN:0736-6299    

DOI:10.1080/07366299608918360

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Linear solvation energy relationships are used to estimate the interfacial tension at solvent/water interfaces for systems containing ‘dry’ and ‘wet’ solvents. The correlation analysis works also in the systems containing Primene 81R and metal salts. The models

ISSN:0736-6299    

DOI:10.1080/07366299608918361

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

IR, NMR (H,13C and31P) and electronic spectroscopies have been used to study the tautomeric forms of 3-phenyl-4-benzoyl-isoxazol-5-one, "HPBI", and its interaction with tri-rc-octylphosphine oxide, ‘TOPO’, in wet toluene or benzene, and in chloroform. These metal extracting media have been compared with analogous solutions containing l-phenyl-3-methyI-4-acyI-pyrazoI-5-oIs. The spectroscopic results are compared with those of molecular modelling studies. Spectroscopic criteria that allow a choice between the various tautomeric forms of pyrazolones or isoxazolones are briefly reviewed.

ISSN:0736-6299    

DOI:10.1080/07366299608918362

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Extraction of Sc, Mn(II), Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Pd, Ag, Cd, In, Sb(III), Te(IV), Ta, W. Pt, Au, Hg, TI(III), Pb, Bi, Th and U from hydrochloric acid solutions by a number of phosphoryl-containing azapodands with an o-phenylene fragment located between the phosphoryl group and the polyester chain has been investigated. The influence of the reagent structure, the nature of an organic solvent, and the compositions of the organic and aqueous phases on the process of extraction is considered.

ISSN:0736-6299    

DOI:10.1080/07366299608918363

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A supported liquid membrane has been used to dissolve selectively copper oxalate from a suspension of copper, calcium and cadmium oxalate, which have low, similar solubilities. 2-Hydroxy-5-nonyl-acetophenone oxime (HX) dissolved in kerosene was used as a carrier for copper transport from the suspension to the stripping solution. A mathematical model of the copper permeation is presented. The model takes into account the dissolution kinetics of CuC204-1/2H20, the diffusion of copper ions through an aqueous stagnant layer, the chemical reaction at the aqueous/membrane interface, and the diffusion of the CuX2complex in the membrane. The model fits the experimental data well with a unique parameter set, except for the transport from an acetate buffered system, for which a lower rate constant for the reaction at the membrane interface had to be assumed. In a separate set of experiments the dissolution of copper oxalate hemihydrate in water was found to be surface reaction controlled.

ISSN:0736-6299    

DOI:10.1080/07366299608918364

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor