Comparison of the performance of flow-by three-dimensional cylindrical electrochemical reactors with inner or outer counter electrode under limiting current conditions

• A reactor with outer counter electrode presents the best performance.
• The potential distribution in a cylindrical arrangement can be theoretically predicte.
• The surface electrode area of a three-dimensional electrode is not equally accessible.

The influence of the position of the counter electrode on the behaviour of a cylindrical electrochemical reactor with a three-dimensional electrode in flow-by configuration is analysed. Experimental results of the potential distribution are compared with theoretical predictions obtaining a close agreement between them. The best performance was observed for the arrangement with an outer counter electrode, where the largest bed thickness is obtained for a given potential difference in the three-dimensional structure; which, under limiting current conditions, tolerates a higher current increasing the conversion per pass. The reactor was also checked for the removal of copper from dilute solutions and the experimental results coincide with the theoretical predictions. The morphology of the electrodeposited copper is discussed as a function of the radial position inside the three-dimensional structure.