RADIOTRACER STUDY OF ADSORPTION OF HSO4- AND SO4(2-) IONS ON A SMOOTH COPPER ELECTRODE IN ACID AND NEUTRAL MEDIA

The absorption of S-35 labeled HSO4 and SO4(2-) ions was studied in acid (0.1 mol dm-3 HClO4) and neutral (0.05 mol dm-3 KClO4) media at a smooth copper electrode. The experimental results obtained in acid medium and the character of adsorption closely coincide with those reported for copper electrodes with high real surface area. However, the work with the smooth surface shows that adsorption is fast, and most probably controlled by diffusion of sulfates to the electrode. In neutral solutions, the extent of adsorption does not differ from that obtained in acids despite the fact that in the former environment the anions interact predominantly with a copper oxide or hydroxide surface layer, rather than with a clean metal electrode.