A study of the effects of competing ions on the biosorption of metals

The effects of ionic competition in the biosorption of metals have been studied for the metals palladium, gold, uranium, yttrium, silver and nickel on the basis of their Pearson classification using biomass from two strains of bacteria. The selection of appropriate pairs of metals permitted the examination of combinations of metals representative of each class (A, B, borderline). The biosorption results obtained from solutions containing each pair of metals have been compared to the corresponding single metal biosorption results. Our results have shown that elements belonging to either the hard or soft classes exhibited competition effects among members of their class. Borderline elements were affected by the presence of either hard or soft elements. This work suggests that Pearson's reasoning is a useful tool. However, a more detailed examination of metal solutions (hydrolysis behaviour, stereochemical) and biomass characteristics is necessary for the proper understanding of the ionic competition effects.