Diffusion coefficients of iodide in high temperature aqueous solutions

The diffusion coefficients of iodide in water solutions containing NaHSO4 as supporting electrolyte have been measured between 102 and 215 degrees C using a high-temperature wall-tube cell. The temperature behavior of the diffusion coefficients is well described by the Arrhenius law and the activation energy for the mass transport is 17 kJ mol(-1). The results are compared to those calculated from the iodide conductivity at infinite dilution and to recent results from other authors. The solvation and speciation of the iodide ion in aqueous solutions at high temperature are analyzed. (C) 2000 Elsevier Science S.A. All rights reserved.