Abstract: Using collagen fiber as matrix,the immobilized myrtan tannins (IMT) was prepared through aldehyde cross-linking reaction.As a novel adsorbent,its abilities of recovering Pb²⁺,Cd²⁺and Hg²⁺ from waste water were studied.(Experiments) showed that the sequence of adsorption capacities of the metal ion on the adsorbent were Hg²⁺ >Pb²⁺ >Cd²⁺.The adsorption capacity was related to pH value of solution.The highest adsorption capacity of Hg²⁺(occurred) at pH value 7.0,whilst those of Pb²⁺ and Cd²⁺ occurred at pH value 3.0.Under the optimized pH value conditions,the equilibrium adsorption capacity of Hg²⁺ on the IMT was 198 mg/g and those of Pb²⁺ and Cd²⁺ were 87 and 24 mg/g respectively,when adsorption process was undertaken by using 0.1 g IMT and 100 mL metal ion solution with initial concentration 200 mg/L.The characteristic of adsorption kinetics and the influence of temperature on (adsorption) isotherms were investigated,both indicated that Hg²⁺ is mainly chemically adsorbed by the IMT,the (adsorption) of Pb²⁺ includes chemical and physical processes and that of Cd²⁺ is primarily due to physical association.These are related to the forms of metal ions in aqueous solution. It was also found that,when more than one metal ion existed in aqueous solution,the equilibrium adsorption capacity of each ion was not affected by others,implying that the IMT adsorbent is effective in simultaneous removal of these ions.

Key words: immobilized tannins, myrtan tannins, collagen fiber, environmental protection