Studies on the synthesis and properties of hydroxyl azacrown ether-grafted chitosan

The chitosan hydroxyl azacrown ether was synthesized by reaction of hydroxyl azacrown ether with epoxy-activated chitosan. The C-2 amino group in chitosan was protected from the reaction between benzaldehyde and chitosan to form N-benzylidene chitosan. After reaction with epichlorohydrin and azacrown ether, reacting O-aryl mesocyclic diamine-N-benzylidene chitosan and dilute ethanol hydrochloride solution to obtain novel chitosan-azacrown ether bearing hydroxyl removed the Schiff base. Its structure was confirmed with elemental analysis, FTIR spectra analysis, X-ray diffraction analysis, and solid-state C-13 NMR analysis. Its static adsorption properties for Ag(I), Cd(II), Pb(II), and Cr(III) were also investigated. The experimental results showed that the hydroxyl azacrown ether grafted chitosan has good adsorption capacity and high selectivity for Ag(I) in the coexistence of Pb(II) and Cd(II), the selectivity coefficients of hydroxyl azacrown ether chitosan were K-Ag(I)/Pb(II) = 32.34; K-Ag(I)/Cd(II) = 56.12. (C) 2001 John Wiley & Sons, Inc.