Effects of solution pH on the voltammetric behaviour of ferrous/ferric ions at zeolite-modified electrodes

Abstract

The redox reaction of Fe 2+/Fe 3+ ions at zeolite-modified electrodes is influenced by the solution pH in such a way that the redox peak currents in the cyclic voltammograms increase almost linearly with the H + ion concentration in the pH region of ca. 2.0–1.0 but at pHs above ca. 2.0 the redox peaks disappear. The observed pH dependence is discussed in terms of the participation of an equilibrium reaction involving H + ions in the redox process in the zeolite cavities.