Abstract: The adsorption of Cd²⁺ and Pb²⁺ onto dominant dead bacteria in natural water was studied. The results show that when Langmuir and Freundlich isotherm models were tried to represent the equilibrium data of Cd²⁺ and Pb²⁺ adsorption onto dominant dead bacteria， equilibrium data fitted very well to both the models in the studied concentration range of Cd²⁺ and Pb²⁺. The kinetic processes of the adsorption included fast phase and slow phase. Pseudo first-order and pseudo second-order kinetic models were also applied to experimental data on the basis of assuming that the external mass transfer limitations in the system can be neglgected and the adsorption is sorption controlled. The slow phase obeyed the second-order rate expression.

Key words: dominant bacteria, lead(Ⅱ), cadmium(Ⅱ), kinetic models of second-order adsorption