Electro-oxidation of phenol on zeolite/graphite composite electrodes Part 1. Electrochemical behaviour over NaY zeolite

in this work, the electrochemical oxidation of phenol was studied on a zeolite/graphite composite electrode. This electrode is prepared by a simple mixture of the two components (NaY zeolite and graphite in a 2:1 proportion) and pressing, to produce a pellet. The zeolite/graphite composite electrode pellet is mounted on a support that uses a platinum disc to ensure electrical contact. The oxidation of phenol was studied by cyclic voltammetry and a well-developed wave, due to the oxidation of phenol, is observed. When the concentration of phenol is sufficiently low, the electrode is not fouled by the electrochemical process and the change in the concentration of phenol induces a reversible change in the intensity of the oxidation wave. For higher concentrations of phenol it is likely that some deposition of oxidation products occur at the electrode surface and inactivation is observed. The overall process seems to be due to the oxidation of the species that is inside the porous volume of the electrode system and not to diffusion-controlled processes involving the solution bulk. Electro-oxidation of phenol over zeolites may have a significant bearing for applications either in the removal of these pollutants or, for example, the production of fine-chemicals. (c) 2005 Elsevier B.V. All rights reserved.