Azo dyes adsorption in fixed bed column packed with different deacetylation degrees chitosan coated glass beads

Abstract

Chitosan with different deacetylation degrees (DD) was used to coat glass beads by dip coating technique, and the coated beads were applied in fixed bed adsorption of tartrazine and sunset yellow from aqueous solutions. Chitosan DD 85% was the best adsorbent in relation to the coating and bed performance for dye adsorption. The adsorption capacity increased with temperature increase as demonstrated by the equilibrium isotherms, which were performed in batch assays using chitosan coated glass beads; the data were suitably fitted by BET model (R2 > 0.95 and ARE < 5%). The best performance attained in the fixed bed assays was using chitosan DD 85%, being the breakthrough time of 90 min, the column maximum adsorption capacity around 60 mg g−1 and removal percentage of 50.4%. The breakthrough curves were well represented by Yoon–Nelson model (R2 > 0.95 and ARE < 10%). The elution efficiency was of 82% in the fourth adsorption–desorption cycle.