Theoretical Analysis of a Flow-By Electrochemical Reactor with Porous Cathode for the Simultaneous Removal of Different Metal Ions

Abstract

A model for a flow-by porous electrode electrochemical reactor operating under galvanostatic conditions has been used to study the removal of two different metal ions. The effect of the applied electrical current was investigated and the concentration, current and electrode potential distributions were calculated. Applied electrical current was used instead of a constant potential as a boundary condition.For a low applied electrical current (-3.5 Am-2), conversions of 54 and 5% were obtained for the first and second component, respectively, with a calculated cathode potential drop of (94 mV); a relatively homogeneous current distribution was observed, with a consequently efficient use of the porous cathode volume. For higher values (-10 Am-2), the first component was almost completely removed, whereas only 70% of the second compound was deposited and a larger cathode potential drop was estimated (477 mV). Moreover, a less homogeneous current distribution was obtained and the electrode volume was not used as efficiently as in the case of a lower applied current. These results have important implications in the ultimate reactor design and its analysis and evaluation, since uneven deposits would eventually provoke localized deposit buildup and flow channeling as well as poor reactor performance. Good agreement was observed between experimental and theoretical results published by other authors and the model presented here.