摘要:

The quantitative description of synergistic solvent extraction systems is usually a difficult problem in equilibrium analysis because a relatively large number of species can be involved. Both sophisticated methods of interpretation and extensive experimental data are required. The graphical methods of “slope analysis”and “continuous variation”provide useful guidance only when the minimum number of species is present and especially when there are no competing reactions between the two synergistic extractants. A general least squares computer program (SXLSQ)is described to deal with the general case in which many possible species must be considered. It will accept six different kinds of equilibrium data for a given system in a single data set and can be used interactively at a terminal. Analysis of data on the extraction of Mn(II) by an organophilic sulfonic acid in combination with each of two crown ethers showed that a unique identification of the species formed cannot be made without additional information about the degree of association of the sulfonic acid in the organic diluent. But narrow limits could be placed on ratios of the integers defining the principal species formed.

ISSN:0736-6299    

DOI:10.1080/07366298708918551

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The partition coefficients and organic-phase dimerization constants of benzoic acid and three short-chain congeners of aliphatic carboxylic acids were investigated. In order to determine them, the “standard potential strength”was introduced for the first time. In low concentrations a carboxy-lie acid has been generally assumed to be almost exclusively monomeric in an organic phase, but the amount of its dimer form was not found to be negligible even in rather low concentrations. As its concentration increased, a proportion of the dimer form increased. In the cases of some nonpolar solvents, a nearly complete dimerization could occur at high concentrations. Although the partition coefficient and dimerization constant of an organic acid have been considered constant irrespective of acid concentrations in an organic phase, a closer observation suggested they should not be constant. This paper also reports the results of a comparative investigation on the degree of self-association (v) the modified potential strength and the half-dimerization concentration (Ch)among the carboxylic acids.

ISSN:0736-6299    

DOI:10.1080/07366298708918552

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The extraction rate of copper(II)from aqueous acetate buffer solutions into Versatic Acid 10 dissolved in kerosene has been investigated using a constant interfacial-area unit cell. Two alternative kinetic equations were derived under the assumption of Langmuir adsorption isotherm for the organic phase - interface distribution of extractant. Experimental results show that the overall reaction is controlled by the formation step of the second intermediate complex,CuR HR, and that the forward extraction rate is proportional to the copper concentration in the aqueous phase, inversely proportional to the hydrogen ion concentration and proportional to a more complex function of the Versatic Acid 10 concentration.

ISSN:0736-6299    

DOI:10.1080/07366298708918553

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The synergic extraction of Co(II) with 1-phenyl-3-methyl-4-benzoylpyrazol-5-one(HPMBP)in presence of acyclic polyethers Butex (dibutylcarbitol)and Triton X-100 (noted E)from TM chloride media in 1,2-dichloroethane, toluene, chloroform and chlo-roform+toluene is quantitatively described. The extracted species are Co(PMBP)E whatever the aqueous electrolyte is (sodium, potassium, lithium and tetramethylammonium chloride) The extractions are compared to the ones performed with the crown-ethers 18C6 and DC18C6B.

ISSN:0736-6299    

DOI:10.1080/07366298708918554

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The extraction of Cu(II)from 1.0 mol.dm−3KN03by the anti-isomer of the 5,8-diethyl-7-hydroxydodecan-6-oxime, the active component of LIX 63, dissolved in toluene, has been studied as a function of the total extractant concentration, equilibrium pH and the total metal concentration. Experimental data treated both graphically using curve-fitting methods as well as numerically by means of the LETAGROP-DISTR program, can be explained by the presence of three different types of extracted species for which the stoichiometric extraction constants have been determined.

ISSN:0736-6299    

DOI:10.1080/07366298708918555

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Solvent extraction equilibria of zinc(II)with five 6-diketones(HA)in carbon tetrachloride-aqueous 1 mol dm−3NaN03systems are studied in the absence and presence of tetrabutylammonium ions(tba+The distribution data of zinc(II)in the absence of tba+ are explained in terms of extractions of uncharged ZnA2 complex from the aqueous phase where the ZnA+, ZnA2and ZnA3complexes are formed, and those in the presence of tba+ in terms of extraction of the ZnA3~tba+ ion-pairs in addition to the uncharged one. The extraction of the ZnA3-tba+species is better with hexafluoroacetylacetone than with trifluoroacetyl-acetone. It is better when the extractant is benzoyltri-fluoroacetone than when it is trifluoroacetylacetone and this is explained in terms of a greater increase in the hydrofobic character by formation of the tris-complex from the bis-complex with the larger ligand. However, the extraction with acetylacetone and benzoylacetone is not affected by though the formation of the tris-chelate with these ligands in the aqueous phase is recognized from the extraction curves. No explanation can be given at the moment for the poor extractability of the most stable tris-complexes among those studied.

ISSN:0736-6299    

DOI:10.1080/07366298708918556

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The mass transfer of Eu(III) Tb(III),Am(III)and Cm(III)through HDEHP solid supported liquid membranes has been studied. The best experimental conditions to perform Am(III)-Cm(III),Eu(III)-Tb(III)and Eu(III)-Am(III) separation have been found. The coefficients of separation of the above mentioned pairs have been determined to be equal to 5.0, 10.8 and more then 102, respectively.

ISSN:0736-6299    

DOI:10.1080/07366298708918557

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

At the Whiteshell Nuclear Research Establishment, the solvent used In the flowsheet examined for reprocessing thorium fuels is tri-n-butyl phosphate (TBP)in a mixture of aromatic (diethyl benzene, DEB)and aliphatic (Isopar M, supplied by Esso Chemical Canada Limited7rpar;diluents. Degradation studies described in this report have focused on the effect of exposure of this solvent to nitric acid. A comparative study of the nitric acid degradation of this solvent, with binary mixtures of TBP/lsopar M and TBP/DEB solvents, as well as each of the individual solvent components is described. The behavior of the major degradation products in washes with NaOH, H2o and HNO3, and the metal retention properties of the degraded systems are also examined

ISSN:0736-6299    

DOI:10.1080/07366298708918558

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The extraction of HC104and HN03by N,N'-dimethyldioctyl malonamide (DMDOMA)an extractant of trivalent actinides from highly acidic solutions was investigated by distribution ratio measurements and IR spectroscopy. HCIO., is extracted as HDMD0MA+with an extraction constant of 4.15. HN03is extracted as HN03(DMDOMA)2,The extraction constant value for these species are respectively : The different behavior of HCIO,, and HN03has been attributed to their different acid strength, HC10-being a much more stronger acid than HN03.

ISSN:0736-6299    

DOI:10.1080/07366298708918559

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The extraction by TRUEX solvent of14C-labelled acetic, glycolic, and citric acids, and14C-labelled glycine, EDTA, and ethylenediamine has been studied from aqueous solutions having different nitric acid concentrations. Only acetic and citric acids are extracted to a significant extent. Their behavior can be compared to that of oxalic acid. If the aqueous phase contains a high concentration of aluminum and iron(III) species, as in some nuclear waste solution, the extraction of aqueous complexants into the organic phase is strongly suppressed. By measuring distribution ratios of irradiated14C-labelled acetic acid, citric acid and EDTA, it has been demonstrated that the radiolytic degradation of these compounds leads, at least in part, to oxalic acid. A scrub procedure, utilizing basic aluminum nitrate, has been successfully tested in order to remove any co-extracted oxalic acid from the TRUEX solvent.

ISSN:0736-6299    

DOI:10.1080/07366298708918560

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor