The acid dissociation constants of glucosamine·HCI, chitosan·HCI and crosslinked chitosan·HCI with epichlorohydrin were determined by pH titration with alkaline, followed by Henderson-Hasselbalch plot. The mean coordination numbers and stability constants of thitosan based chelating polymers-metal ions such as Cu(Ⅱ), Pb(Ⅱ), Cd(Ⅱ), Hg(Ⅱ), Cr(Ⅳl) and UO₂(Ⅳ) were determined by using a modified Bjerrum''s method proposed by Gregor and co-workers. The results were compared with the values obtained between glucosamine and metal ions. The order of the stability constants of metal ions to the chitosan was as follows; Cu(Ⅱ)> Hg(Ⅱ)> Cr(Ⅳ)> UO2> Pb(ll)> Cd(H) for the crosslinked chitosan the order was; Hg(Ⅱ)> Cu(Ⅱ)> UO2(Ⅳ)> Cr(Ⅳ)> Pb(Ⅱ)> Cd(Ⅱ). The order of the stability constants of chelating polymers and glucosamine to Cu(Ⅱ), Hg(Ⅱ), UO2(Ⅳ) and Cr(Ⅳ) ions was following sequence; chitosan > crosslinked chitosan> glucosamine. For Pb(Ⅱ) and Cd(Ⅱ) ions the order was reverse.

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