Surface conductivity measurements for porous carbon electrodes

Abstract

A method for measuring the surface conductivity in porous electrodes was developed. The knowledge of surface conductivity is very important for simulation and optimization of the capacitive deionization of aqueous solutions, which is a new promising and economical method for water desalination. The surface conductivity (SC) is the tangential (longitudinal) conductivity of a double electric layer (DEL). The SC involves the conductivity induced by the conductivity of the counterions of the surface groups in a highly disperse carbon electrode κsg and the surface conductivity κsch induced by the electrostatic charge of the inner surface of the electrode pores and the charge-compensating ions of the solution, i.e., the classical DEL. The value of κsg depends on the concentration of the surface groups C sg on carbon, i.e., their exchange capacity, and κsch depends on the potential E. SC measurements were performed on activated porous carbon electrodes CH900 and SAIT. This SC measurement procedure is another method for studying DEL.