The effect of surface active substances on the electrochemical behaviour of copper ions in chloride solutions and in natural waters

Abstract

Electrochemical methods have been used in the study of the adsorption behaviour of different surface active substances, biogenic and non-biogenic, as well as in the study of their complexation properties for copper ions in chloride solutions and in natural waters. The influence on the anodic oxidation wave of copper has been examined. For surface active substances (humic substances and proteins), which at the same time exhibit complexation properties towards copper ions, the main interaction will be complexation, especially in the lower concentration range of both copper and the organic substance. At higher concentrations of the surface active substances and copper ions adsorption effects may play a role in oxido-reduction processes of copper at the electrode surface covered with organic coating. Contrary to cadmium, the electrode reaction of copper is not greatly influenced by synthetic surface active substances like Triton X-100 and sodium dodecylsulphate, since in the potential range of the anodic wave of copper most synthetic surface actice substances are desorbed from the mercury electrode surface. In natural samples the main interaction will be complexation of copper ions with the organic matter. Investigations of the interfacial interactions between copper and organic coatings have to be continued on the other surfaces, natural and/or model ones, which have different surface properties and will be of greater environmental significance. Mercury electrode/solution interface is not a very convenient model for the study or interfacial interactions of copper ions because of the nature of the electrode process of copper.