COORDINATIVE INTERACTION OF CHITOSAN-AZO DYES TOWARDS SELECTED FIRST ROW TRANSITION METALS

Abstract

Chitosan is an abundant bio-polymer obtained by alkaline deacetylation of chitin in the exoskeleton of crustaceans. Chitosan was found to be an attractive alternative to other bio materials due to its significant physicochemical behavior and ability to selectively bind to transition and post transition metals. In order to improve the performance of this bio-polymer, chemical modification of chitosan composite and its derivatives have gained much attention. In this study, a new biopolymeric ligand was synthesized by functionalizing chitosan with eriochrome black T (EBT) and sudan III (S3) dyes. The functionalized compounds were interacted with Co(II), Ni(II), Cu(II) and Zn(II) metal ions at varied concentrations leading to complex formation. Both the new ligand and the complexes obtained at high yields were characterized using Fourier Transform Infrared (FT-IR) and Uv-Vis Spectroscopy. The FT-IR spectra revealed a possible hydrogen bonding between chitosan and the azo dye. It also suggests an interaction between the N=N of the ligand with the metal ions. In addition, the Uv-Visible spectra studies showed that on reacting various concentrations of metal ions with ligand the absorbance increases with decreasing concentration of the metal ions and was able to interact with as low as 0.001 M of the studied metal salts.