A STUDY OF THE EFFECTS OF COMPETING IONS ON THE BIOSORPTION OF METALS

The effects of ionic competition in the biosorption of metals have bee n studied for the metals palladium, gold, uranium, yttrium, silver and nickel on the basis of their Pearson classification using biomass fro m two strains of bacteria. The selection of appropriate pairs of metal s permitted the examination of combinations of metals representative o f each class (A, B, borderline). The biosorption results obtained from solutions containing each pair of metals have been compared to the co rresponding single metal biosorption results. Our results have shown t hat elements belonging to either the hard or soft classes exhibited co mpetition effects among members of their class. Borderline elements we re affected by the presence of either hard or soft elements. This work suggests that Pearson's reasoning is a useful tool. However, a more d etailed examination of metal solutions (hydrolysis behaviour, stereoch emical) and biomass characteristics is necessary for the proper unders tanding of the ionic competition effects. Copyright (C) 1996 Published by Elsevier Science Limited