Biionic Potential of Charged Membranes: Effects of the Diffusion Boundary Layers

Abstract

The biionic potential of charged membranes has been studied theoretically. A closed, analytical solution to the Nernst-Planck equations describing the multiionic transport through the charged membrane and the diffusion boundary layers has been obtained. Several limiting expressions, corresponding to negligible diffusion boundary layer effects, low bathing solution concentration, and low fixed charge concentration, have been discussed, and the experimental conditions which ensure their validity have been analyzed. The results from the model have been finally compared to recent experimental data corresponding to membranes with high charge density, and the influence of the boundary layers has been found to be significant.

Electrochemical characterization of polymer ion‐exchange bipolar membranes

“…The NaCl concentration in the left compartment, cL, was taken as the reference concentration and kept constant during each experimental series, and different values for the ratio cRIcL were considered. Since other experimental data in the ion-exchange literature show that the effects of stirring are more noticeable in this region [54], the disagreement between theory and experiment can be due to the existence of hydrodynamic diffusion bound- ion-exchange membranes [54,[85][86][87], and taking for the ion diffusion coefficients in the DBLs their respective values at infinite dilution, a good agreement between theory and experiment is achieved (see Fig. The solutions were stirred vigorously by means of magnetic stirrers.…”

Transport of chromium through cation-exchange membranesby Donnan dialysis in the presence of some metals of different valences

“…Donnan dialysis is an ion-exchange membrane process that can be used for the purification and concentration of diluted solutions [1][2][3][4][5][6][7][8][9] and is generally applied in analytical fields where the preconcentration of various cations and anions is performed. The process was often studied by means of cation exchange with the H + ion as the *Corresponding author.…”

Studies on electrochemical characterization and performance prediction of cellulose acetate and Zeocarb-225 composite membranes in aqueous NaCl solutions

“…We found in such cases that (D ± · C · d/ D M ± C M · δ) is proportional to water content of the membrane. It is the fact that the water state in the membrane phase may differ from that in the solution phase [21]. Diffusion coefficients in the membrane phase may be affected due to ion hydration.…”