Electroanalytical Techniques Applied for Studying the Interaction of Organic Matter and Particles with Metal Ions in Natural Waters

Abstract

Electroanalytical techniques were applied and proved suitable for studying the adsorption of metal ions, metal organic complexes and organic ligands on different mineral particles (γ-Al2O3, SiO2, northupite and chrysotile). The complexing capacity of the model solutions with added adsorbents were determined. The complexing capacity and apparent stability constants for a mixture of organic ligands present in a seawater sample for different metal ions (Cu ions, Pb ions and Cd ions) were determined by voltammetry as well. Mercury electrode surface was used as a model of hydrophobic surface and the oxido-reduction processes of the cadmium ions on the mercury surface covered with the layer of humic acid were studied by phase selective a.c. voltammetry. By simple voltammetric measurements it was possible to determine the extent of adsorption of organic matter and its influence upon the speciation scheme of trace metals and organics.