Mechanistic aspects of the sonoelectrochemical degradation of the reactivedye Procion Blue at boron-doped diamond electrodes

Redox processes of the reactive dye, Procion Blue, at polycrystalline boron -doped diamond film electrodes, in buffered aqueous solution are studied as a function of pH, dye concentration and ultrasound treatment. Direct parti al oxidation with a four electron transfer, within the solvent window up to 2.5 V vs. SCE in PBS, at pH 2 is possible. However, more extensive degrada tion of Procion Blue does not occur at potentials below that required for s olvent decomposition. Oxidation is most easily achieved in acidic solution and at low dye concentrations, as evidence of fouling of the electrode surf ace was noted under more alkaline conditions and at higher dye concentratio ns. The dye is also found to influence redox processes which are directly a ssociated with defect sites on the diamond electrode itself. (C) 2001 Elsev ier Science B.V. All rights reserved.