ELECTROCHEMICAL CHARACTERIZATION OF CARBON PASTE ELECTRODES MODIFIED WITH NATURAL ZEOLITE

Abstract

A comparative study between carbon paste electrodes (CPE) modified with natural zeolite (ZMCPE, 20 and 50 wt.% clinoptilolite as a major phase) and unmodified CPE (UCPE) is reported. The electro-oxidation of reactive azo-dye (C.I. Reactive Blue 69) was used as a probe to evaluate the performance of these materials. In order to understand the electro-catalytic behavior, cyclic voltammetry (CV), linear sweep voltammetry (LSV), and real time (i-t) techniques were performed. It was found that ZMCPE presents different anodic processes in both free and azo-dye based solutions as a function of zeolite concentration, compared to UCPE. According to the i-E characteristic, in a solution containing azo-dye compound, ZMCPE (50 wt.% oz zeolite) presents major catalytic activity in acid conditions, as revealed by UV-vis spectroscopy. Particle size-shape distribution and structural-textural properties in the zeolite framework and onto the CPE bulk, compared to UCPE electrodes, promote this catalytic effect.