Electric conduction in electrolytes takes place as ions are transported by means of diffusion, convection, and migration in an electric field. In this context, electrophoresis is the motion of charged species relative to the fluid under the influence of a spatially uniform electric field. The electrophoretic effects can be used to separate charged species with different mobilities, for instance, during chemical analysis. Furthermore, the effects are central when describing mass transport in electrochemical cells, such as batteries, fuel cells, and electrolysis processes.
Modeling such applications involves combining material balances for each of the individual
species and a total charge balance for the electrolyte. The balance equations need to be fully
coupled in the electrolyte region.
Transport in an Electrokinetic Valve
The animation shows the ion concentration during the injection stage of a sample preparation process. A clean separation of the sample ions is important, and different configurations of the electric field can be tested to achieve this.