Crosslinked chitin was prepared by the reaction of epichlorohydrin with chitin which was isolated from waste marine sources. The crosslinhed chitosan of deacetylation degree of 0.635 was prepared by the deacetylation of the crosslinhed chitin with crosslinking degree of 0.145 per N-acetylglucosamine residue. New chelating polymers such as crosslinked amino deoxy chitin and chitosan were synthesized by the chlorinations of crosslinked chitin and chitosan on the OH groups at C-6 positions with thionyl chloride in DMF, followed by the aminations in aqueous ammonia solution in the presence of KI. The structures of these chelating polymers were conformed by the elementa] analysis and the substitution degrees of amine groups of crosslinked amino deoxy chitin and chitosan were 0.303 and 0.351 per repeating base unit of the polymer, respectively. The anion exchange capacity of these chelating polymers was determined by the titrimetry, the adsorption characteristics towards various meta] ions such as Cu(Ⅱ), Cd(Ⅱ), Cr(Ⅲ), Cr(Ⅳ), Pb(Ⅱ), Hg(Ⅱ) and UO₂(Ⅳ) were examined at different pH by batch method. In the case of the crosslinked chitin, the adsorptivities of the metal ions above pH 5 region were in the order of following sequence ; Hg(Ⅱ)>UO₂(Ⅳ)>Cr(Ⅲ)>Pb(Ⅱ)>Cd(Ⅱ) Cu(Ⅱ) The adsorption tendency of the crosslinked chitosan to the metal ions was similar to that of the crosslinked chitin. However, adsorption rate of Hg(Ⅱ), Cu(Ⅱ) and UO₂(Ⅱ) were increased up to 95%. The adsorptivities of the crosslinked amino deoxy chitin to the metalions showed some increase as compared with the crosslinked chitin by dative bonding by -NH₂ ligands introduced, for the adsorption rates of Cu(Ⅱ), Pb(Ⅱ), UO₂(Ⅳ) and Cr(Ⅲ) to the crosslinked amono deoxy chitosan were increased more than 95% by introducing -NH₂ ligands. The adsorptivities of these chelating polymers to the metalions were increased with the increase of pH. However, Cr(Ⅳ) existing oxyanions such as Cr₂O₇^-2 and Cr₂O₄^-2 showed different adsorption tendency showing maximum adsorptivity at pH 2. The adsorptivities to the metalions and the anion exchange capacity of these chelating polymers were in the order of following sequence; crosslinked amino deoxy chitosan>crosslinked chitosan>crosslinked amino deoxy chitin>crosslinked chitin, and the sequence was in accordance with the content of primary amine groups on the polymers.

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