The Effect of Some Surface Active Substances on the Polarographic Reduction Process of Metallic Ions

Abstract

Abstract The effect of three detergents on the polarographic electrode reduction processes of Tl+-, Pb2+- and Ni2+-ions was studied together with the E-C curve of these detergents. It was shown that these detergents were very effective to suppress the polarographic maximum and their surface excess was shown to be very small at the concentration range of their MSP from the study of the E-C curve. The half-wave potential was shifted to the more negative and the shape of the c-v curve was distorted by the presence of these detergents, the degree of which was the largest in the case of Ni2+-ion and the least in the case of Tl+-ion. The anionic detergent seemed to have a larger effect than the cationic one on the electrode process with the half-wave potential more positive than the E-C max., and vice versa. It was shown that the effect of the detergents on the polarographic c-v curve was parallel to the result on their adsorption phenomena obtained from the E-C curve. From these results it was concluded that the polarographic electrode process is greatly influenced by the change in the structure of the electrical double layer and that it will be the electron-transfer process which is mainly affected by the presence of the adsorption layer of the surface active substances.