Preparation of chromium (III) ion-imprinted polymer based on azo dye functionalized chitosan

The main aim of this work is the preparation of azo dye modified chitosan that was subsequently used in the ion-imprinting of Cr(III) ions to finally obtain ion-selective sorbent able to selectively combine with Cr(III) ions from water when coexisting with other similar metal ions. The azo dye derived from resorcinol and p-aminobenzoic acid was prepared and then linked to the chitosan amino groups by amide linkages utilizing EDC/NHS coupling agent. A polymeric complex of the azo dye chitosan derivative AZCS and Cr(III) ions was then prepared and treated with glyoxal solution, which cross-link the main chitosan chains in form of micro-spherical beads in presence of the coordinated Cr(III) ions that were later expelled out of the texture of the beads using acidified EDTA eluent solution while preserving the spatial and geometrical shape of the resulting Cr(III) ions chelating sites.