3.2.5. Comparison of thermodynamic parameters between
the adsorption of lac dye on untreated and pretreated
cotton with chitosan
Under the same conditions, the amount of the dye adsorbed
on pretreated cotton with a 0.3% (v/v) aqueous solution of
chitosan was higher than that on the untreated cotton as shown
in Fig. 8. This may be due to the protonated amino group of
chitosan interacting with both cellulose and the lac dye, and
acting like a binder between the two which results in higher
dye adsorption. In addition, the amount of the dye adsorbed
on pretreated cotton with chitosan was also higher than that
on the untreated cotton in the presence of 0.5 M NaCl without
pH control, supporting the important binding role played by
the chitosan.