No abstract

A selective and effective solvent extraction method has been developed for the separation of cadmium(II) using Cyanex 923 in toluene. Cadmium(II) was quantitatively extracted using 0.1 M Cyanex 923 in toluene from 1.0 M ammonium thiocyanate media. The extracted cadmium(II) was quantitatively stripped with 3.0 M nitric acid from organic phase and determined spectrophotometrically with PAR at 520 nm. The optimum extraction conditions have been evaluated by studying parameters such as ammonium thiocyanate concentration, Cyanex 923 concentration, equilibration time, various diluents, diverse ions, and stripping agents. The selective and sequential separation of cadmium(II) from other cations was achieved in binary as well as multicomponent mixtures. The method was extended for the separation of cadmium from spent nickel-cadmium batteries, some aquatic plants and zinc blende. The reliability of the method is assured by a comparison of the results with those obtained using AAS.

A poly[dibenzo-18-crown-6] exhibits good chemical stability, reusability, and faster rate equilibrium for the separation of Gd(III). Both uptake and stripping of metal ions were rapid, indicating a better accessibility of the complexing sites. The proposed method has been applied for chromatographic separation of Gd(III) by using picric acid as medium and poly[dibenzo-18-crown-6] as stationary phase. The influences of picric acid concentration, different eluting agents, and so forth, were discussed and the optimum conditions were established. The breakthrough capacity of poly[dibenzo-18-crown-6] for Gd(III) was 0.572±0.01 mmolg-1 of crown polymer. The proposed method has been applied to sequential chromatographic separation of their binary and multicomponent mixtures. Gd(III) has been determined from real samples with good analytical reliability.