Synthesis and adsorption properties of metal ions of novel azacrown ether crosslinked chitosan

Azacrown ether chitosan (CTSC) was synthesized by the reaction of chitosan with N-allyl benzo 15-crown-5 crown ether. Azacrown ether crosslinked chitosan (CCTSC) was prepared by the crosslinked reaction of CTSC and epichlorodydrin. Their structures were confirmed by infrared spectral analysis and X-ray diffraction analysis. The adsorption properties of CTSC and CCTSC for metal ions were also investigated. The experimental results showed that the two chitosan derivatives not only had a good capacity to adsorb Pd 2+ and Ag + but also was highly selective for Pd 2+ and Ag + in the coexistence system containing other metal ions. At 20°C ± 1°C and pH = 4, the adsorption capacity of CTSC and CCTSC for Pd 2+ was 186.1 and 173.1 mg/g, respectively; and for Ag + was 90.2 and 56.5 mg/g, respectively. The selectivity coefficients were K Ag - /Ni 21 = 6.99, K Ag + /Cu 2+ = ∞, K Pd 2+ /Pb 2 = 35.38, K Pd 2+ /Cu 2+ = ∞ for CTSC and K Ag + /Ni 2+ = 10.66, K Ag + /Cu 2+ = ∞, K Pd 2+ /Pb 2+ = 85.45, K Pd 2+ /Cu 2+ = ∞ for CCTSC.