DIFFUSION BEHAVIOUR OF TRIVALENT METAL IONS IN AQUEOUS SOLUTIONS

Trivalent metal ions have a relevant impact on different kinds of industry; for example, indium(III) and europium(III) ions are of practical importance in the development of new semiconductors and luminescent probes, respectively. Transport properties of ions and salts in aqueous solutions are important physico-chemical parameters allowing a better understanding of the behaviour of these ions in the solution and so, helping to describe better the mechanism of processes taking place in their presence. However, the measurement of those transport properties is complicated due to the occurrence of hydrolysis; that may justify the scarcity of e.g. diffusion data for aqueous solutions of europium(III) and indium(III) chlorides. In this study mutual diffusion coefficients for aqueous solutions of InCl3 and EuCl3 in a concentration range from 0.002 mol x dm(-3) to 0.01 mol x dm(-3) at 298.15 K are reported. The open-ended conductometric capillary cell was used. The results are discussed on the basis of the Onsager-Fuoss and Pikal models.