摘要:

Data are reviewed on the formation of third phase in the extraction of acti-nide(IV.VI) nitrates by neutral organophosphorus extractants, mainly tributyl phosphate. The data are critically evaluated and the effect of variables on the third phase formation is discussed. The variables are the concentrations of nitric acid and the extractant, temperature, the nature of diluent, addition of modifiers and the ionic strength of the aqueous phase. Also discussed are systems involving two extracted actinide ions.

ISSN:0736-6299    

DOI:10.1080/07366299608918378

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The extraction of alkali metal nitrate salts by solutions of crown ethers in each of the two diluents 1,2-dichlorethane and 1-octanol has been surveyed. The crown ethers include 18-crown-6, 21-crown-7, and 24-crown-8 ethers bearing cyclohexano, benzo, t-alkylbenzo, and/or furano substitutents. The extraction efficiencies of the different crown ethers are examined in terms of ring-size, substituent, and solvent effects. Partition ratios for the crown ethers between water and either 1,2-dichloroethane or 1-octanol are discussed. The extraction selectivities, expressed as the separation factor for cesium over sodium, are examined in relation to crown ether structure.

ISSN:0736-6299    

DOI:10.1080/07366299608918379

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The influence of different solvents on the extraction ability of aliphatic non - chelating aldoximes with respect to CuCl2, NiCl2and CoCl2has been investigated with heptanaloxime as an example. The effect of carbon tetrachloride, toluene, chloroform, 1,2-dichloroethane, caprylic acid on syn-antiisomerization and aggregation of heptanaloxime has been studied and the constants of these processes have been calculated. It has been shown also it was aldoxime anti - isomer that formed the extracted complex with metals. The equation of state of non-chelating aldoximes in the extraction systems has been deduced.

ISSN:0736-6299    

DOI:10.1080/07366299608918380

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The synergistic extraction of copper (II) from 1M NaN03 aqueous solutions with acidic chelating extractants HL = 3-phenyl-4-acylisoxazol-5-ones (acyl = benzoyl, "HPBI", and p-tert-butylbenzoyl, "HPtbBI") and 1-phenyl-3-methyl-4-acylpyrazol-5-ones (acyl = benzoyl, “HPMBP”, p-tert-butylbenzoyl, “HPMtbBP” and stearoyl, "HPMSP"), in the absence and presence of trx-n-octylphosphine oxide (TOPO) in toluene at 25°0, has been studied. The TOPO-HL interaction, which is one order of magnitude stronger with 4-acylisoxazol-5-ones than with 4-acylpyrazol-5-ones, strongly influences the synergistic extraction efficiency. The extracted species are CuL2and CuL2(T0P0). Because of their higher acidity, the extractions performed with 4-acylisoxazol-5-ones occur at a lower pH range than with 4-acylpyrazol-5-ones.

ISSN:0736-6299    

DOI:10.1080/07366299608918381

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The interfacial activity of 2-hydroxy-5-l-butylbenzophenone (E)-oxime (HBBO), two model a-acyloin oximes: 9-hydroxy-8-hexadecanone oxime (HHO) and 13-hydroxy-12-tetracosanone oxime (HTO), and a model modifier such as p-tertbutylphenol (BPh) is investigated at toluene/ water interface, at 21°C. Interfacial tension isotherms for individual compounds as well as for binary mixed solutions are obtained. In particular, it is shown that in all mixed systems co-adsorption is observed. Composition of mixed adsorption monolayer is affected mainly by mutual efficiency of adsorption of surface active components and composition of the bulk solution phase.

ISSN:0736-6299    

DOI:10.1080/07366299608918382

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A new chelating ion exchange resin, Diphonix®, containing geminally substituted diphosphonic acid ligands bonded to a styrene-based polymeric matrix, was recently developed and characterized. To overcome some of the problems associated with the stripping of actinide elements from the resin, a new version of the Diphonix resin has been prepared, where the chelating diphosphonic acid groups are grafted to a silica support. The new material is called Diphosil, for Diphonix on silica. The properties of the new material have been investigated with regard to its equilibrium and kinetic behavior in the uptake of actinide and other ions from acidic solutions. In this work data comparing the Diphonix and Diphosil resins are presented and discussed. The Diphosil resin appears particularly well suited for those cases where the recovery and further processing of the sorbed actinides is not required and the loaded resin can be considered as a solid waste. Because about 90 % of the Diphosil resin weight is silica, the problem of possible generation of gaseous compounds due to the slow radiolytical degradation of the organic components of the resin is minimized.

ISSN:0736-6299    

DOI:10.1080/07366299608918383

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The extraction of uranium from various acid media such as nitric acid, sulphuric acid, hydrochloric acid, phosphoric acid and perchloric acid by a macroporous bifunctional phosphinic acid resin (MPBPA) has been studied. The distribution coefficients for the extraction of uranium by the MPBPA resin are compared with the corresponding values reported in literature for the conventional sulphonic acid resin. The results clearly indicate the suitability of the MPBPA resin to recover uranium from different types of acid solutions of widely ranging acidities.

ISSN:0736-6299    

DOI:10.1080/07366299608918384

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The ion exchange kinetics of DL-lysine monohydrochloride on Amberlite IRA-420 have been studied. Ionic diffusivity of hydroxyl anion, which is supposed to be equal to the interdiffusion coefficient, has been evaluated by fitting experimental kinetic data to a theoretical model based on the continuity equation of the CI" anion in solution filling the pores of the resin. Because of changes of both viscosity with ionic concentration and co-ion behavior in solution at high concentrations, a variation of ionic diffusivity of hydroxyl anion has been observed. In order to predict the dynamic behavior of fixed beds a simple mathematical model including both equilibrium isotherm and ionic diffusivity of hydroxyl anion has been developed. Likewise, resin regeneration using NaOH solutions has been investigated. The results show the feasibility of the procedure of purification and regeneration and they have been used to design a plant for the treatment of 50 Tm/yr of DL-lysine monohydrochloride.

ISSN:0736-6299    

DOI:10.1080/07366299608918385

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Ion-Exchange equilibria of alkaline earth metal ions (M = Mg2+, Ca2+, Sr2+, and Ba2+) /H+systems was studied on tin(IV) antimonate (SnSbA) in [M(NO3)2-HNO3] media at 30, 45, and 60°C. The ion-exchange isotherms showed sigmoidal curves without hysteresis effect for each ion-exchange system. The plots of the logarithm of the selectivity coefficient (In Kc) vs. equilibrium fraction (X¯M) of alkaline earth metal ion in the exchanger could well be described by two straight lines which intersect at about X¯M= 0.2. The slope of the straight line at X¯M< 0.2 increased in the order Mg2+< Ca2+< Sr2+< Ba2+. Overall and hypothetical (zero loading) thermodynamic data were evaluated from the plots. The selectivity sequence on (zero loading) was Mg2+< Ca2+< Sr2+< Ba2+while the overall affinity sequence was Sr2+< Ba2+< Ca2+< Mg2+.

ISSN:0736-6299    

DOI:10.1080/07366299608918386

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor