• Journal of environmental and Sanitary engineering
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• v.16 no.2
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• pp.91-99
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• 2001

Cross linked chitosan beads showed high selective adsorption abilities in order of $Au^{3+}$ > $Hg^{2+}$ > $Cu^{2+}$ > $Cd^{2+}$ > $Pt^{4+}$ > ${UO_2}^{2+}$ ions in mixed solution of various metal ions at pH 4.5. N-methyltyiobenzylated chitosan beads(MTB-chitosan beads) were prepared treating with p-(methylthio) benzaldehyde after cross linking of chitosan beads to give them a high selectivity in adsorption of metal ions. The MTB-chitosan beads demonstrated their selectivity on precious metals among various metal ions distinctively. Particularly, the MTB-chitosan had a peculiar selective adsorption on $Pd^{2+}$, $Au^{2+}$, and $Hg^{2+}$ions whilst the cross linked chitosan beads showed its high adsorption on $Pd^{2+}$ at pH 1.1. On the other hand, the cross linked chitosan beads showed its superiority in selective adsorption on $Au^{2+}$, $Cu^{2+}$, and $Hg^{2+}$ions to the MTB-chitosan at pH 4.5 of the test solution. Thus metal selectivities were given to chitosan beads through chemical modifications.