Separation of Monovalent Cations by Electrodialysis

Electrodialysis has been used to separate sodium and cesium ions in aqueous solution. Experiments utilizing a Nafion 417 cationic membrane and an RAI Raipore R-1030 anionic membrane in a three-compartment cell resulted in an increased flux of cesium over sodium through the cationic membrane. A maximum separation efficiency ranging from 2 to 3 was observed at currents below the mass-transport-limited plateau. At currents above the mass-transport-limited value, the separation efficiency decreased to approximately 1.27, which compared well with that determined by the relative ionic mobilities. When the flow rate of the anolyte, catholyte, and feed was varied, it was shown that the process scaled linearly, which demonstrates the potential for large-scale equivalent ion separation by electrodialysis.