Application of the network simulation method to study the electrical response of ion-exchange membrane systems to pulsed electric fields

Abstract

The transient electrical response of an ion-exchange membrane system to square shaped electric perturbations not only when the electric potential is the externally controlled variable but also when an electric current is imposed through the system, has been simulated using the network simulation method. The system under study is constituted by a cation-exchange membrane in which the fixed-charge is homogeneously distributed in space and two diffusion boundary layers on both sides of the membrane, the electric double layers at the interfaces being included. The time evolution of the counterion flux exiting from the system in response to a pulsed electric potential has been analyzed in order to establish the conditions in which the use of transient techniques in ion-exchange membranes can lead to intensification of the efficiency of electrodialysis. Also, the time evolution of the system electric potential in response to a pulsed electric current is analyzed and discussed. The counterion quantity exiting from the system and the energy consumption in pulse mode are evaluated and compared to those obtained from stationary electrodialysis.