SELECTIVE BEHAVIOR OF HYPERFILTRATION CELLULOSE-ACETATE MEMBRANES .2. STREAMING POTENTIAL

Streaming potentials have been measured by the fast pulse method for cellulose acetate membranes cured at 85 and 95 degree C. Bounding solutions of Li** plus , Na** plus , K** plus , plus , Mg**2** plus , Sr**2** plus , Ba**2** plus and La**3** plus chlorides were used in the concentration range of 10** minus **4-10** minus **1 M. The streaming potential was shown to depend on the nature of the cation and to increase with decreasing solution concentration. Rather good consistency was obtained in dilute solutions between the electroosmotic cross coefficients calculated from the streaming potentials and from the electroosmosis measurements of Part I of this report according to the Onsager reciprocal relations. The deviation observed at higher concentrations, independent of the cation nature, is attributed to concentration polarization and/or excessive water transport encountered in electroosmosis measurements. Determination of additional phenomenological coefficients of the same system permitted an estimation of the effective exchange capacity of modified cellulose acetate membranes.