Single particle studies of binary and ternary cation exchange kinetics

Extensive ternary ion‐exchange rate data for cases where particle‐diffusion is important are presented. Experimental rate data, using a single‐particle radioactive‐tracer technique, were obtained for the following systems in Dowex 50W‐X8 resin: Mn‐Cs‐Na, Ba‐Mn‐Na, and Sr‐Mn‐Cs. Nernst‐Planck equations have been used to describe the ternary ion‐exchange kinetics. The Nernst‐Planck model, when used for the correlation of binary and various types of ternary exchange data obtained under unfavorable equilibrium conditions, usually cannot afford to disregard liquid‐film resistance. The model incorporating the film effects correlated satisfactorily most of the experimental data, and even in cases where the correlation was not good, it interpreted adequately the trend of the results.