Effect of cross-linking with glutaraldehyde on adsorption capacity of chitosan beads

The study was undertaken to analyze the effect of chitosan cross-linking with glutaraldehyde on the adsorption capacity of chitosan beads during adsorption of Reactive Black (RB5) and Basic Green (BG4) dyes. Analyses were conducted at three pH values: pH 3.0; 5.0 and 9.0. Results obtained were evaluated with the use of four models of adsorption isotherms Freundlich, Langmuir, Double Langmuir and Redlic-Petreson. The cross-linking of beads with glutaraldehyde turned out to be beneficial for the anionic dye RB5. Compared to the non-cross-linked beads, a comparable adsorption capacity (over 500 mg/g d.m.) was obtained at pH 3.0 and pH 5.0. In the case of the cationic dye, chitosan cross-linking reduced the quantity of adsorbed dye, irrespective of the pH value of the adsorption process.