Abstract
In this study, chitosan is crosslinked with epichlorohydrin for structural stability. The crosslinked chitosans are phosphorylated by trimethyl phosphate-$POC1_3$ reaction and $H_3P0_4$-DMF reaction. The crosslinked chitosan and chitosan phosphates were dipped in $Cu^{2+}$, Cd, Pb and $UO_2^{+2}$ solution in different conditions of ppd concentration and pH of metal ion solutions and dipping period. The chitosan phosphate by trimethyl phosphate-$POC1_3$ reaction had selective adsorption properties, which it absorbed a little copper ion as low as 10%. Chitosan itself has good adsorption ability on copper ion. But chitosan phosphate iffy $H_3P0_4$, -DMF reaction could absorb much more copper ion than crosslinked chitosan, when their crosslinking percent were higher than 15%. The metal binding ability of chitosan was improved by phosphorylation reaction, when the concentration of metal solution was high or the amount of dipping solution was increased.
