Adequacy of isotherm adsorption of black 5 reactive dye for crosslinked chitosan microspheres

Abstract

Chitosan microspheres with average diameter 1.03 ± 0.06 mm and degree of deacetylation of 72.5% were employed as adsorbent for reactive dye black 5. Chitosan was characterized through infrared spectroscopy (IR), 13 C NMR spectrum and deacetylation degree (DD%), and crosslinked with glutaraldehyde 2.5% (w/v) to increase its resistance in acid medium. Corresponding isotherms were obtained in acid and alkaline solutions. Experimental data were fitted by Langmuir’s, extended Freundlich’s and Nernst’s isotherms. Adsorption was more effective in acid medium and adjusted better the Langmuir’s isotherm