Abstract: The adsorption rule of Pb²⁺； and Cd²⁺ onto immobilized dominating bacteria in natural water was studied. The results show that the adsorption dynamic process of the heavy metals onto immobilized bacteria includes a fast stage and a slow stage； the latter conforms to secondlevel adsorption rate equation. The Elovich model and the rate model with two constants cannot describe the dynamics process of the Pb²⁺；adsorption onto immobilized bacteria, but can describe the Cd²⁺ adsorption very well. The Henry model can describe the thermodynamics process of heavy metal adsorption, and the affinity for Pb²⁺； is stronger than for Cd²⁺.

Key words: immobilization, adsorption, dynamic model, thermodynamic model, Pb²⁺, Cd²⁺