A new type of grafted chitosan-crown ether was synthesized using mesocyclic diamine crown ether as the grafting agent. The C2 amino group in chitosan was protected from the reaction between benzaldehyde and chitosan to form N-benzylidene chitosan (CTB). After reaction with mesocyclic diamine crown ether of the epoxy propane group to give mesocyclic diamine-N-benzalidene chitosan (CTBA), the Schiff base was removed in a dilute ethanol hydrochloride solution to obtain chitosan-crown ether (CTDA). Its structure was confirmed by FTIR spectra analysis and X-ray diffraction analysis. Its static adsorption properties for Pb(II), Cu(II), Cd(II), and Cr(III) were studied. The experimental results showed that the grafted chitosan-crown ether has high selectivity for the adsorption of Cu(II) in the presence of Pb(II), Cu(II), and Cd(II) and its adsorption selectivity is better than that of chitosan. (C) 2000 John Wiley & Sons, Inc.