摘要:

A comparative investigation on the solvent extraction equilibria of gallium(III) from aqueous nitrate media was conducted with three kinds of acidic organophosphorus compounds, di (2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexyl 2-ethyl-hexylphosphonic acid (EHEHPA) and di (2,4,4'-trimethylpentyl) phosphinic acid (DTMPPA), in toluene at 303 K. It was found that gallium(III) is extracted as 1:4 metal:reagent complexes with D2EHPA and EHEHPA and as a 1:3 complex with DTMPPA in the region of low loading ratio while it is extracted as 1:3 complexes with all reagents at high loading ratio. The extraction equilibrium constants with these extractants were evaluated for the former complexes as follows: Ke= 2.3xl0-2, 8.5xl0-3and 1.3xl0-4for D2EHPA, EHEHPA and DTMPPA respectively.

ISSN:0736-6299    

DOI:10.1080/07366298808917944

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The extraction behavior of Co(II) and Ni(II) by a series of dialkylphosphoric acids, mono-esters of alkylphosphonic acids, and dialkyl phosphinic acids was investigated. The quantitative relationship between the structure and properties of these organophosphorus acids in cobalt and nickel extraction was established based on an analysis of the structural factors that determine the reactivities and separation capabilities of these systems. As expected, polar and steric effects of the substi-tuents of ligands play an important role in cobalt and nickel extraction. The fact that Ni(II) extraction is more sensitive to the substituent than Co(II) can be rationalized by the different steric requirements of the various configurations of the complexes formed during the process.

ISSN:0736-6299    

DOI:10.1080/07366298808917945

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

1,10-diaze [8]crown-6, their N,N'-dibutyl- and dioctyl-substituted derivatives and the structure analogous open-chein tetreoxedieza slkanee have been synthesized in order to examine the extraction properties for Na+, K+, Sr2+and Hg2+. It wes found, that the extraction of strontium, potassium and sodium picratee with azacrown compounds ie much higher than that with open-chein oxaaze alkanes. 1,10-diaze [18] erown-6 has a good selectivity for the extraction of Sr2+over K+and Na in alkaline solution. In the case of Sr2+the diffarencea between tha various azacrown compounds are email, whereea in the caee of K+and Na the substituted derivativee are better extractante. Theserssulte correspond qualitativsly with tha order of stebility conetantB in protic solvsnts. The extrectebility of N,N'-dioctyl-l, 10-dieze[18]crown-6 for HgCl2is very high. Contrerv to the order of stability conetants the uneubetituted conpound do not extract mercury under the choeen experimental condition*. The extraction power of open-chain conpounde ie aleo high and strong Influenced by the alkyl eubatltuente at the nitrogen donor stons,

ISSN:0736-6299    

DOI:10.1080/07366298808917946

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

When strontium(II) and barium(II) were extracted with 18-crown-6(l 8C6) and picrate ions into chloroform, log(distribution ratio of metal(II)) approached flat in a higher region of log[18C6], although it is reported that the distribution ratio of copper(II) or zinc(II) increases in proportion to the second order of 118C6]. From the extraction data analysis, the flat distribution ratio was explained by the formation of the aqueous complex with 18C6 and the stability constants for strontium(II) and barium(II) were determined to be 2.89 and 3.68 as logβ1respectively.

ISSN:0736-6299    

DOI:10.1080/07366298808917947

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The extraction of Am(ITI) and Eu(III) from aqueous 0.1 M NaClO4 using a mixture of 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (HBMPPT) and 4,7-diphenyl-l,10-phenanthroline (DPPHEN) was studied. Individually, neither the HBMPPT nor the DPPHEN in toluene showed any extraction capabilities for Am(III) or Eu(III) under the experimental conditions used in this study. Combination of the two ligands, however, yielded a synergistic system which showed a strong preference for Am(III) over Eu(III). Slope analysis indicated that the extracted species took the form M(BMPPT)3(DPPHEN) for both metal ions studied. The separation factor DAm/DEu was 190 at pH = 3.7, [HBMPPT] = 3.0 x 10-2, and [DPPHEN] = 2.7 x 10-3.

ISSN:0736-6299    

DOI:10.1080/07366298808917948

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The synergistic solvent extraction of Pr, Gd and Yb with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyra-zol-5-one and tri-n-oetylamine in CC14C6H6and CHCl3has been studied The composition of the extracted species has been determined as LnP4TOAH (Ln=Pr, Gd, Yb and P-and TOAH* are the chelating extractant anion and the amine salt cation respectively).The values of the equilibrium constants have been calculated. The extraction mechanism has been discussed.

ISSN:0736-6299    

DOI:10.1080/07366298808917949

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Extraction of HNO3into 0.5M TBGA ((C4H9)2NCO(CH2)3CON(C4H9)2) toluene take3 place via the formation of the following species : (TBGA)2HNO3, TBGA HNO3and TBGA(HNO3)2for which extraction constants values : 0. 7H ± 0.04, 0.50 ± 0.02 and 0.032 ± 0.002 nave been found. Water does not play a role in this extraction. IR Investigations show that only one of the two C = 0 of TBGA is bonded to HNO3. vC=0 IR absorption shifts indicate that in (TBGA)2.HNO3and TBGA HNO3, TBGA and HN03are linked by hydrogen bonds whereas in TBGA(HN03)2one H+ion is transfered from one HN03to one C = 0 of the TBCA, so the formula TBCAH+-N03. HN03is a better representation of this species.

ISSN:0736-6299    

DOI:10.1080/07366298808917950

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The simultaneous ion exchange extraction of selected pairs of noble and base metal cyano complexes was studied. In most cases It was found that equilibrium Is attained only after a period of several hours during which time the resin composition undergoes marked variations. As a rule, the loading of noble metals passes through a maximum value while the loading of base metals Increases steadily as equilibrium Is approached. Kinetic parameters, obtained by applying mathematical models to the experimental data, indicated that there are significant differences in dlffusivity among the various metal cyano complexes in both the Nernst diffusion layer and in the resin matrix. These differences assist in understanding the experimental observations.

ISSN:0736-6299    

DOI:10.1080/07366298808917951

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The removal of cadmium by anion exchange from 55 w% H3PO4(black acid from a Nissan H process) at 90°C in the presence of small amounts of halides (Cl-, Br-, I-) was investigated. Cadmium distribution coefficients, [CD]resin/[CD]acid(concentrations in mol/1), larger than 250 were obtained with HBr equilibrium concentrations of more than 0.10 w% in the phosphoric acid solution or with HI concentrations of more than 150 ppm. The regeneration of the Cd loaded resin was performed with a very dilute phosphoric acid solution (< 1 w% H3PO4).

ISSN:0736-6299    

DOI:10.1080/07366298808917952

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor