Extraction Rate Study of Ni(III) Oxinate & Separation of Cu(II) & Ni(II) with Oxide Based on Differences in Rates of Extraction

This study was conducted with metal ion concentrations in the range of parts per million and used batch extraction techniques to study the non-equilibrium extraction of Cu(II) and Ni(II) oxinates. Contrary to other authors, atomic absorption was used exclusively for the analysis of phases. The two main areas of investigation in this study were: Kinetics study of extraction of Ni(II) oxinate. Separation of Cu(II) and Ni(II) with oxine based on differences in rates of extraction. It was the purpose of this work to study the extraction of Cu(II) and Ni(II) with oxine in chloroform. This particular pair of elements was chosen for study for several reasons. One prominent reason was that these metals form stable complexes with oxine which remain stable upon extraction with various organic solvents. The extraction curves (pH versus percent extraction) were found to lie very close together making it impossible to separate one from the other without the use of masking agents. Another factor which was important to the undertaking of this extraction rate study was the fact that the equilibrium behavior of metal oxinates (and of oxine) distributed between water and various organic solvents had been previously studied in detail. Finally, it was believed that it should be possible to separate the Cu(II) and Ni(II) ions (and perhaps other as well) by a non-equilibrium method even though it was not possible to separate these same two ions by an equilibrium extraction. The present work was aimed at determining the optimum conditions of pH, oxine concentration, shaking time and solvent used for the maximum separation of the ion pair, Cu(II)-Ni(II)