Studies of Ion Exchange Membranes. XXXI. The Hydrogen Peroxide Treatment of the Cation Exchange Membrane of Ferric Ion Form

Neosepta CL-2.5T, the cation-exchange membrane prepared by the “Paste Method,” of the ferric-ion form was treated with hydrogen peroxide, and the changes in the membrane properties (the thickness, the water content, and the ion-exchange capacity) were measured. The porous membrane, having no ion-exchange capacity, was obtained by the treatment with hydrogen peroxide and the water permeation through the membrane was measured. Assuming the capillary model, the water-permeability data of this membrane suggested that the apparent pore radius of this membrane was 15–17 mμ and that the apparent pore distance was about 40 mμ. This suggests that Neosepta CL-2.5T contains a minute and continuous heterogeneity; i.e., there is a localized distribution of the ion-exchange resin component within the membrane.