Abstract
Praseodymium-neodymium mixture solution containing a complexing agent, EDTA or DTPA, was electrically dialyzed. The metals were effectively separated with the help of the complexing agent, while no separation was observed in its absence. The separation factors defined as a flux ratio of praseodymium to nedymium attained 1.7 for EDTA and 2.1 for DTPA. The separation characteristics were affected by the pH of solution and the concentration of complexing agents. All the experimental results were well explained by a model, based on the Nernst - Planck equation, where the selectivities of complexing agents and membranes and the migration in membrane were considered. The model analysis revealed that the separation characteristics for the two metals were estimated from the difference between the concentrations of the free (uncomplexed) metal - ions caused by the difference between the stability constants of the metal complexes.
