Ion exchange and water content measurements were performed with an ani
on exchange membrane, ADS XL 10 (Solvay), equilibrated in aqueous solu
tions containing mineral electrolyte as NaCl, and/or organic electroly
te as sodium benzene carboxylate (Phi CO2Na) and sodium 4-hydroxy-1-na
phthalenesulfonate (Phi Phi OHSO3Na). By using radiotracers, it was po
ssible to determine the amount of the total mineral and organic ionic
species present inside the membrane. The fixation of big organic ions
balancing the exchanging sites of the membrane can modify the membrane
structure, creating micropores able to sorb more electrolytes. It was
established that the sorption of hydrophobic organic ions corresponds
to a 'micelle mechanism', The penetration of hydrophobic ions into th
e membrane induces a change in the molar volume of the wet membrane in
relation to the variation of the water content.