摘要:

In the extraction of zinc(II) from hydrochloric acid solutions by trioctylmethylammonium chloride in various organic diluents such as benzene, chlorobenzene, o-dichlorobenzene, toluene, m -xylene, nitrobenzene, carbon tetrachloride and 2,2-dichloroethane, the heat change associated with zinc(II) extraction has been examined by calorimetry. In the case of benzene used as diluent, it is confirmed that the heat change detected can be interpretated as the summation over the change in enthalpies for the relevant steps to the extraction of zi(II), taking the change in enthalpy obtained from the temperature-dependence of the distribution coefficient into account. Applying this approach of zinc(II) extraction for other diluents, it is found that the distribution of zinc (II) between aqueous and organic phases can be explained very well by assuming a regular solution.

ISSN:0736-6299    

DOI:10.1080/07366298308918408

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The extraction rate of gallium from aqueous NaOH solutions vith the 7-(1-vinyl-3,3,5,5-tetramethylhexyl)-8-quinolinol into kerosene is increased when a vater-in-oil microemulsion is used as organic phase. This microemulsion is formed by adding a surfactant and an alcohol to the extraction system.

ISSN:0736-6299    

DOI:10.1080/07366298308918409

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Mechanistic studies including equilibrium and kinetic aspects of palladium extraction from acidic chloride media with 2-hydroxy-5-nonylbenzophenone oxime (LIX 65N) in chloroform solution are reported. The extracted species was established to be PdL, and the extraction equilibrium constant K Tor the reaction:

ISSN:0736-6299    

DOI:10.1080/07366298308918410

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The loading of a 30 vol.%solution of tributyl phosphate in do-decane with large amounts of thorium(IV), uranium(IV) or pluto-nium(IV) nitrate in the presence of uranyl nitrate causes the formation of a second organic phase, which contains both the acti-nide(IV)and uranium(VI). The presence of uranium(VI) in the third phase is due to physical distribution of uranyl nitrate, solvated by tributyl phosphate, between the two organic phases. Equations are suggested which describe the distribution of some components between the organic phases, and the actinide(IV)to uranium(VI)ratio in the second organic phase. The maximum attainable concentration of actinides(IV)in the organic phase of a two-'liquid-phase system, at which a third phase is not yet formed, was measured and described by an empirical equation as a function of the concentration of uranium(VI) in the organic phase and of nitric acid in the aqueous phase.

ISSN:0736-6299    

DOI:10.1080/07366298308918411

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Extended X-ray Absorption Fine Structure (EXAFS)was used to determine the molecular species obtained in the synergistic extraction of zinc by a benzene solution of TTA [thenoytrifluoro-acetone, or 4,4,4-(trifluoro-l-(2-thienyl)-l,3-butadione]and TBP (tributyl phosphate). The zinc in the extracted complex is surrounded by five oxygen atoms at a distance of 2.01 A. The coordination number is established by the zinc-oxygen distance, which is shown to be characteristic of this type of pentacoordinated zinc compound. The coordination number is also independently determined by direct comparison of an EXAFS function with those obtained from compounds of known structure. The coordination number is in agreement with that concluded by Nash and Choppin from thermodynamic results. The Debye-Waller term for a series of zinc crystals and solutions is discussed.

ISSN:0736-6299    

DOI:10.1080/07366298308918412

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The extraction properties of the dibutyl ester of dibutoxymethane phosphonic acid (DBDBMP) an analog of TBP with a P-C bond, were shown to be similar to those of TBP except for hydrolysis of DBDBMP in acidic solutions. The formation of acidic organophosphorus compounds during hydrolysis of DBDBMP was confirmed by 31P-N.M.R. measurements.

ISSN:0736-6299    

DOI:10.1080/07366298308918413

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The extraction of silver(I) and mercury(II) from nitric acid solutions by dihexylsulfide (DHS, R2S)in benzene has been examined under different conditions. It is found that silver is extracted into organic phase according to the following reactions: at low acidity AgN03(a) + 2R2S(o) 2(R2S)2AgN03(o)and at higheT acidity AgN03(a) + HN03(a) + 2R2S(o) 2(R2S)2AgN03-HN03(o), in which (a) and (o) represent the aqueous and organic phases, respectively. In addition the stoichiometric species, R2S-AgN03and R2S-AgN03-HNO3, are formed when silver loading increases in the organic phase. The similar results are also obtained in the extraction of mercury, although the extraction efficiency of mercury is higher than that of silver.

ISSN:0736-6299    

DOI:10.1080/07366298308918414

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The extraction behavior of Mo from HNO3was studied using dlhexyl-N,N-dlethylcarbamoylmethylphosphonate. Distribution coefficients were measured as a function of contact time, concentration of Mo, HNO3, N03and extractant, and extraction temperature. Above 11 M HNO3, Mo is appreciably extracted.

ISSN:0736-6299    

DOI:10.1080/07366298308918415

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The facilitated transport of HN03through a supported liquid membrane consisting of a porous polypropylene film containing a solution of trllaurylamine 1n diethyl benzene as carrier was studied as a function of the stirring speed of the aqueous solutions and the membrane composition. A physico-chemical model which takes Into account diffusion through an aqueous boundary layer, a fast Interfaclal chemical reaction leading to the formation of a membrane soluble alkylammonium salt and diffusion through the membrane was proposed. In this way, equations were derived which describe how composition changes, occurring In the course of the permeation process, Influence the membrane permeability. The experimental data were quantitatively explained by the derived equations. The results indicate that the monomerlc form of the trllaurylammonium nitrate salt 1s the species which 1s mainly responsible for the acid transport through the membrane. The diffusion coefficient of the permeating species and the order of magnitude of the thickness of the aqueous boundary layer were evaluated.

ISSN:0736-6299    

DOI:10.1080/07366298308918416

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The binding of Ce(III), Eu(III), and Am(III) to a weak carboxylic acid ion exchange resin was measured at several temperatures. The thermodynamic values correspond to contact ion-pair formation of the trivalent cations with the carboxyllc sites. The results of this study of binding of lanthanides and actinides to a weak carboxyllc acid resin are compared to analogous data for a strong sulfonic acid ion exchange resin.

ISSN:0736-6299    

DOI:10.1080/07366298308918417

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor