A systematic study on equilibrium and kinetics of biosorptive accumulation. The case of Ag and Ni

Biosorptive metal uptake capacities have been quantitatively evaluated through a systematic experimental approach for silver and nickel and six selected strains of microbial biomass. Strains MB 127 and BP 7/26 have been identified to be the most efficient for silver sequestering. Biosorption of nickel by the strains tested is generally low. Overall kinetic experiments have been performed for the determination of the necessary contact time for the attainment of equilibrium. Systematic desorption experiments have shown that biosorption of silver and nickel by the strains tested is irreversible under the conditions examined. Simultaneous considerations of hydrolysis behaviour, chemical coordination, and stereochemical and redox characteristics have been proven to be very helpful in understanding the observed differences between silver and nickel biosorptive performances.