Abstract: Modified chitin with 40.4% deacetylation degree was obtained from enzymatic hydrolysis residue of shrimp shell,which was treated by 5% HCl for 4 h and 45% NaOH coupled with 460 W microwave for 10 min,and then prepared into gel beads with diameter of 1.5-3.2 mm by adding sodium alginate,mixing evenly,and squeezing in calcium chloride solution for 12 h.The adsorption performances of the gel beads to metal ions (Pb²⁺,Cr³⁺,Ni²⁺,Cu²⁺,Zn²⁺ and Co²⁺) were investigated.The adsorption rates of Cu²⁺, Co²⁺ and Zn²⁺ were found to be 94.2%,75.6% and 57.3% in 300 mg/L ion solutions by treating for 8 h,and 95.1%, 82.5%, 67.5% in the Cu²⁺, Zn²⁺ and Co²⁺ coexisting system,respectively.

Key words: modified chitin, metal ion, adsorption property