Permselectivity of calcium ion to potassium ion in ion exchange membrane electrodialysis of sugar solution

Abstract

The permselectivity of calcium ion relative to potassium ion, T Ca K , in sugar solution has been studied with an electrodialyzer which consists of eleven pairs of anion exchange membranes, Selemion AMV, and cation exchange membranes, Selemion CMV. The experimental results show that T Ca K decreases as the current density and the equivalent ratio of potassium ion to calcium ion, R, increase, and increases as the flowrate and the total concentration of diluent increase, but is independent of the sugar concentration of the diluent. By means of dimensional analysis and correlation of the experimental results, T Ca K is found to be a function of Stanton number St and the feed ion ratio R, and can be expressed by the equation T Ca K = 0.0119 × St − 0.85 R − 1.18 . The results also indicate that T Ca K appraoches (Z Ca /Z K )(Ū Ca /Ū K )α Ca K and (D Ca /D K ) [(Z Ca − Z Cl /(Z K − Z Cl ) ] as the current density approaches zero and the limiting current density, respectively.