Concentration separation in the binary electrolytes

Abstract

In the paper the numerical solution of Nernst–Planck equations is considered taking into account the Poisson equation. The proposed difference scheme was used to solve a pair of problems with two components: the ambipolar diffusion and the liquid junction. It is shown that the concentration level critical for the Planck condition depends on the concentration gradient to the power 2/3. This dependence allows one to estimate the applicability of the Planck condition to different electrochemical systems.