Collect. Czech. Chem. Commun. 1981, 46, 3027-3037

Pulse polarography of heavy metal ions in polyelectrolyte solutions: Behavior of Pb2+ and Cd2+ in PMA solutions

Herman P. Van Leeuwen, Wim F. Threels and Rob F. M. J. Cleven

LABORATORY FOR Physical and Colloid Chemistry, Agricultural University, De Dreijen 6, 6703 BC WAGENINGEN, The Netherlands


An orientational study is presented of the pulse polarographic features of Pb2+ and Cd2+ in aqueous solutions of polymethacrylic acid, partially esterified. Normal pulse polarography with varying pulse duration was applied, and the resulting Cottrell plots were used to check the diffusion-controlled character of the currents. Values for binding constants under various conditions are presented. It could be established that the binding of Pb2+ increases with decreasing Pb2+/PMA ratio, which is a typical polyelectrolytic effect. It is in accordance with indications from Henderson-Hasselbalch analysis of the NPP current data. Variation of the pH, corresponding with variation of the overall charge on the polymer, confirms the polyelectrolytic character of the binding. The latter finding is also supported by indications from experiments at different electrolyte concentrations. At rather negative initial potentials and sufficiently low Cd2+/PMA ratio the polarograms for Cd2+ show the maxima which are typical for induced reactant adsorption.