Abstract
Effects of coexisted ions other than Na+ in sea water and brine on specific resistance were measured for two kinds of commercial membranes.
1. In case of cation membrane, its specific resistance was increased by adsorption of magnesium and calcium ions, but it was decreased by potassium. The specific resistance of the membrane in sea water was about two times as compared with that in 0.5N sodium chloride solution. With an increase in the concentration of external solution, the resistance became lower because of an increase in the amount of Donnan's absorption.
2. In case of anion membrane, its specific resistance was increased by adsorption of sulfate ion, but the effect of sulfate ion was small.
3. The specific resistance of the cation membrane in the solution of multi-component systems such as sea water and brine approximated to the summarized parallel resistance of the partitioned membrane of component ion type, the area of which was equal to the product of the total membrane area and the absorption factor of each component ion.
4. In case of the cation membrane in sea water and brine, absorption factors of calcium and magnesium ion were fairly greater than that of sodium ion.
5. The amount of ion of Donnan's absorption showed a lower value as compared with its theoretical value when the concentration of the external solution was above 1N. This phenomenon was considered to be due largely to the shrinking effect of the membrane.
