Electrochemical studies of the interaction between a modified activated carbon surface and heavy metal ions

Abstract

Cyclic voltammetric studies of the influence of surface chemistry on the electrochemical behaviour of powdered activated carbon electrodes (PACE) in the presence of selected heavy metal ions (Pb2+, Hg2+, Cd 2+) in bulk solution and pre-adsorbed on carbon were carried out. The variety of surfaces was achieved via the modification of carbon samples by heat treatment under vacuum and in an oxygen/ammonia atmosphere, as well as oxidation with cone, nitric acid. The chemical structures of the modified carbon surfaces were characterised by XPS and standard pH-titration. The adsorption capacities of the modified carbon samples towards the heavy metal ions in question were estimated. The mechanisms of adsorption processes of metal species on carbon surfaces were analysed and described on the basis of their electrochemical behaviour. The nature of the interactions between the modified carbon surfaces and adsorbed cations is discussed. © Springer 2005.