Abstract: The biosorption of Pb²⁺ by the organic components(exopolymer,nonliving body bacterium and living bacterium) on the dominant bacterium obtained from the surface coatings in natural waters and the effects of biosorption time,temperature and initial pH were investigated.The results showed that Pb²⁺ biosorption process by the organic components above was divided into fast phase and slow phase,biosorption equilibrium time was 360,120 and 150 min respectively;the biosorption ability of exopolymer is much higher than nonliving body bacterium and living body bacterium,the maximum biosorption amount of Pb²⁺ was all reached at pH=6,the effect of temperature on the biosorption ability of nonliving body bacterium and living body bacterium was negligible;both the Longmuir and Freundlish could describe the course of the biosorption of on Pb²⁺ by the organic components.the biosorption ability of exopolymer is much higher than nonliving body bacterium and living body bacterium;the thermodynamics experiments also carried on when the Cd²⁺ was present,the biosorption of Pb²⁺ by the three organic components was also followed the Langmuir and Freundlich(equation),but the biosorption amount and the saturated biosorption amount of Pb²⁺ was decreased.

Key words: Exopolymer, Nonliving body cell, Living body cell, Biosorption