Synthesis and adsorption properties for metal ions of crosslinked chitosanacetate crown ethers

Two novel chitosan derivatives - crosslinked chitosan dibenzo-16-c-5 acetat e crown ether (CCTS-1) and crosslinked chitosan 3,5-di-tert-butyl dibenzo-1 4-c-4 diacetate crown ether (CCTS-2)-were synthesized by the reaction of cr osslinked chitosan with dibenzo-16-c-5 chloracetate crown ether and 3,5-di- tert-butyl dibenzo-14-c-4 dichloracetate crown ether with the intent of for ming polymers that could be used in hazardous waste remediation as toxic me tal-binding agents in aqueous environments. Their structures were confirmed with elemental analysis, infrared spectral analysis, and X-ray diffraction analysis. In the infrared spectra of CCTS-1 and CCTS-2, the characteristic peaks of aromatic backbone vibration appeared at 1595 cm(-1) and 1500 cm(- 1); the intensity of the N-H and O-H stretching vibration in the region of 3150-3200 cm(-1) decreased greatly. The X-ray diffraction analysis showed t hat the peak at 2 theta = 20 degrees decreased greatly in CCTS-1 and CCTS-2 . The adsorption and selectivity properties of CCTS-1 and CCTS-2 for Pb2+, Cu2+, Cr3+, and Ni2+ were studied. Experimental results showed that the two crosslinked chitosan derivatives had not only good adsorption capacities f or Pb2+, Cu2+, but also high selectivity for Pb2+ Cu2+ in the coexistence o f Ni2+. For aqueous systems containing Pb2+, Ni2+, or Cu2+ Ni2+, CCTS-1 onl y adsorbed Pb2+ or Cu2+. For aqueous systems containing Pb2+, Cr2+ and Ni2, CCTS-2 had high adsorption and selectivity properties for Pb2+. (C) 1999 John Wiley & Sons, Inc.