The ion exchange accompanied by chemical reaction (complex formation) of platinum second triad elements have been investigated. The ion exchanger m-DVB and Formylstyrene as crosslinking agent and functional monomer, respectivelly was newly prepared. The selectivity (K) and average charge (ν) of the complexes on the ion exchangers were observed by applying ν-K locus method. The selectivities of Ru (III) and Rh (III) increased with increasing chloride ion concentration. Pd (II) complex showed the more complicated behavior. The average charge numbers of Ru (III), Rh (III) and Pd (II) -chloride complexes on the ion exchanger were-1.42, -1.59 and-1.68, respectively and those were-2.98, -1.97 and -1.96, in 6 mol/dm³ HCl solutions respectively. These tendencies, were the average values in ion exchanger were lower than those in the solutions, were not according with the data observed by ion exchange equilibria in the case of many ions including transition metal-chloro complexes. It led to suggestion that the platinum group elements reacted with the ion exchange radicals to form the complex as well as chloride ion.

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The experimental method in electrodialysis process is outlined.
The following matters are important as pre-treatment for effective proceeding of experiment.
(1) Study of literature inquiry to membrane manufacturer regarding similar applica tion.
(2) Clarification of the test purpose.
(3) Conceptual design of the process.

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Ion transport phenomena across a membrane such as membrane potential and ion permeability have been explained using Nernst-Planck ion flux and Donnan equilibrium theories. They are predicted as a function of membrane charge density, ion mobility and solution concentration. Membrane charge density is one of the important parameters to characterize a charged membrane and defined as concentration of fixed charge groups in it, that is, those numbers per unit volume of water (If it is defined as an amount of charge per unit weight of dry membrane, it is called as ion exchange capacity.) . It is based on the solution of Nernst-plank's ion flux equation, where it implies that tubular pores with water exist in the membrane for ion penetration. It has been pointed out that the fixed charge groups are distributed in the membrane heterogeneously. On the contrary it is assumed that the fixed charge groups are distributed homogeneously if Donnan equilibrium theory is applied to the charged membrane. These are the contradiction on the analysis of the membrane transport phenomena, and have been used without any deep consideration. In this paper the effect of fixed charge density on the membrane potential and the permeability coefficient was explained from the fundamental point of view in order to understand the problems cited above. Therefore it is helpful for developing further advanced ion exchange membranes.

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