Studies on the adsorption of anionic dyes on chitosan

Abstract

Abstract Equilibrium adsorption measurements of three anionic dyes on chitosan, under acid conditions, show that there is a 1 : 1 stoichiometry for the interaction of sulfonic acid groups on the dyes with protonated amine groups of the chitosan for mono‐, di‐ and trisulfonated dyes. Comparison of the extents of N ‐acetylation calculated from equilibrium dye adsorption values with those determined by IR spectroscopy, for a series of chitosan samples covering a wide range of N ‐acetylation values, demonstrates that equilibrium adsorption measurements may be used for the analysis of chitin and chitosan.