The activated carbon electrode : a new, experimentally-verified mathematical model for the potential distribution

Activated carbon (AC) is an increasingly important electrode material for such applications as electrosorption, electrosynthesis, and electrical energy storage. An accurate description of the potential distribution within the electrode is essential to understanding the overall process behavior in all of these applications. Simple models developed for electrodes composed of solid materials do not accurately predict the potential behavior of AC packed bed electrodes. A new model is presented which more realistically takes into account the complex physical structure of AC beds. An intraparticle microporosity as well as the classical interparticle macroporosity are treated. Equations describing the potential distributions in both of these porous phases are solved with finite difference techniques. The model is experimentally verified over a range of operating parameters including electrolyte conductivity, potential step direction and initial value, and activated carbon type. Very good agreement is found between the model predictions and the experimental results.