MEASUREMENT AND THEORETICAL DESCRIPTION OF ION SORPTION AND DIFFUSIONOF WATER AND COUNTERIONS IN A CATION-EXCHANGE RESIN BEARING SULFONIC-ACID GROUPS

Sorption of LiCl, diffusion of Li+ ions, and diffusion of water have b een studied as a function of the salt concentration in a synthesized c ation-exchange resin bearing sulfonic acid groups, The Li+ diffusion s hows a maximum in the salt concentration dependence reflecting on one side the enhanced diffusion due to screening of the fi?ted charges on the charged matrix and on the other hindered diffusion by shrinking of this matrix. A theoretical analysis is given in which the resin is vi sualized as being composed of spherical cells with the charged spheres placed in the centers. Also, the phenomenological approach of Gluecka uf(4, 5) is applied. The spherical cell model gives a semi-quantitativ e prediction of the observed sorption and diffusion. The experimental results agree nicely with the semi-empirical power laws of Glueckauf. (C) 1997 Academic Press