摘要:

Three programs develpoed to analyze data for liquid-liquid extraction of metal have been applied to the calculation of the stability constants of aqueous cadmium(II)-thiocyanato complexes by using the data for the extraction of tricaprylmethylammonium salt in benzene. The resulting stability constants of the aqueous thiocyanato complexes determined were: for the trial and error method log β1= 2·97, log β2= 3·70, log β3=3·50 and log β4=3·28; for the Gauss method log β1= 2·91, log β2= 3·70, log β3=3·35 and log β4= 3·29; for the Newton-Gauss method for log β1= 2·47, log β2=3·24, log β3=2·29 and log β4= 2·85

ISSN:0736-6299    

DOI:10.1080/07366298408918473

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The paper deals with the mechanism of increasing the selectivity of some bathoferroine (tris/bathophe-nanthroline /iron/II/cation) ion pairs by adding selected nonelectrolytes to the water phase. The dependence of the bathoferroine cation hydration number and extraction selectivity on the concentration of the nonelectrolyte and temperature has been found. The dependence of the extraction selectivity on ethanol concentration in the water phase with various solvents as the organic phase has been investigated, too. Moreover, the solvation number (ethanoi) of ion association compounds tested in conditions of the best extraction selectivity has been determined

ISSN:0736-6299    

DOI:10.1080/07366298408918474

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The separation of Co from Ni by the new extractant di (2,4,4-trimethylpentyl)phosphinic acid, H(DTMPP) or CYANEX 272, was studied by liquid-liquid extraction and by supported liquid membranes, SLM. The following extraction stoichiometrics and conditional equilibrium constants were evaluated using toluene as organic diluent and [NH4NO3[ = 0·3 M as aqueous medium Co2+ + 2 (R^fp ^ Co(HX2)2 + 2H+, Ke = 6 x 10"8 Ni2+ + 3 (H^) 5* Ni(HX2)2.(H2X2) + 2H+, Kg = 1 x 10"10 where H2X2is the dimeric form of H(DTMPP). The extraction of Co and Ni was also studied using the diluent mixture 67% decalin + 33% diisopropylbenzene, which is compatible with the polypropylene membrane supports, and a 1 M acetate buffer aqueous medium

ISSN:0736-6299    

DOI:10.1080/07366298408918475

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The use of an organophosphinic acid to separate cobalt from nickel by solvent extraction is described. Comparative data indicate that the phosphinic acid is superior to analagous phosphoric and phosphonic acids in terms of cobalt-nickel selectivity and the ability to reject calcium. Important reagent properties, such as low aqueous solubility and hydrolytic stability, are discussed. The results of continuous, counter-current, mini-plant tests demonstrate the recovery of high purity cobalt from concentrated nickel sulphate solutions.

ISSN:0736-6299    

DOI:10.1080/07366298408918476

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A variety of alkyldiammonium extractants (tertiary and quaternary)were prepared, characterised and used to extract cobalt(II) and copper(II) from HCl medium. These extractants were compared with Aliquat-336 and Alamine-336. The diammonium derivatives of ethylene diamine proved to be superior to their mono analogues.

ISSN:0736-6299    

DOI:10.1080/07366298408918477

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The extraction of tris(raalonato) chromate(III) by solutions of Aliquat-336 in various organic solvents such as n-pentane, n-heptane, cyclohexane, chloroform, carbon tetrachloride, o-xylene,benzene, toluene, nitrobenzene and nitromethane has been studied. The effect of the organic solvent on the extraction is correlated with their solubility parameters by application of the theory of regular solutions. The solubility parameter of the extracted species is reported.

ISSN:0736-6299    

DOI:10.1080/07366298408918478

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The rate of extraction of copper(II) from aqueous chloride solutions by tri-n-laurylammonium chloride (TLAHC1) dissolved in toluene has been investigated. The extraction rate was evaluated as function of the chemical composition of the system. The experiments were performed by using a stirred cell with constant inter-facial area. The experiments were performed at a stirring rate of the two phases where the influence of film diffusion is minimized. The data have been interpreted by a mechanism which assumes interfacial chemical reactions between the bulk species containing copper(II) and the molecules of TLAHC1 absorbed at the interface as rate determining.

ISSN:0736-6299    

DOI:10.1080/07366298408918479

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The synergic extraction of the different lanthani-des, except Pm and Lu, by thenoyltrifluoroacetone (HTTA) and triphenylphosphine oxide (TPPO) mixture in benzene from an aqueous perchlorate medium of constant ionic strength of 0·2 was investigated. It was found that the main adduct extracted contains the lanthanide chelates together with two TPPO molecules. The different extraction and formation constants for the lanthanides investigated have been determined. The variations of the logarithmic values of the chelate extraction constant and the adduct formation constant with the different lanthanides was discussed in the light of the tetrad and the inclined-W effects. The experimental results showed that the nature of coordination by adduct formation for the Yb-Sm group is different than that of the Pr-La group.

ISSN:0736-6299    

DOI:10.1080/07366298408918480

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Synergism in the extraction of Zn(Il) and Cd(II)with chloroform solution of propionic, butyric and valeric acids in the presence of n-butylamine, dibutylamine, tributylamine, β-picoline, pyridine and quinoline is reported The effect of various parameters affecting extractions has been investigated The compositions of synergistic adduct extracted into the organic phase have been proposed on the basis of slope analysis method. In general the species have been represented as MA2.2HA.B (aliphatic amine system and MA2.2HA.2B (heterocyclic amine system), where M = zn(Il)/CdII), HA = acid and B = amine. On the basis of extraction constant (Kex) values the relative effectiveness of different amines as synergists has been compared. Based on the extraction data some separations of metal ions have also been reported with fairly high separation factor (β).

ISSN:0736-6299    

DOI:10.1080/07366298408918481

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A new approach based on the Nernst-Planck equations has been applied to study the reaction kinetics on the surface of tin(IV) tungstate for the Mg(II)-H(I), Ca(II)-H(I), Sr(II)-H(I) and Ba(IT)-H(I) exchanges under the conditions favouring a particle diffusion phenomenon. On the basis of these studies the various physical parameters such as the effective diffusion coefficients, activation energies and entropies of activation have been evaluated which give some informations regarding the mechanism of ion-exchange on the surface of inorganic materials.

ISSN:0736-6299    

DOI:10.1080/07366298408918482

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor