Electric Field Enhancement of Donnan Dialysis

Abstract Donnan dialysis of cations into simple receiver electrolytes such as NaNO3 is inhibited by interaction between the fixed sulfonate exchange sites on the cation exchange membrane and the test cations. Application of a 5 V cm−1 (peak-to-peak) sine wave at 1 MHz across the membrane diminishes the retardation and allows the Donnan dialysis rate to approach the diffusion limit with Cd, Cu, and Zn test metals and a 0.1 M NaNO3 receiver. The transport to Pb is still retarded by about 25%. The use of 0.2 M Mg(II), 0.5 mM Al(III) receiver results in diffusion limited transport for all metals.