Dye removal from aqueous solutions by sorption onto chitosan derivatives

In this study, the removal of a basic dye from aqueous solution was investigated by sorption onto chitosan derivatives. The sorbents were prepared by grafting poly(acrylic acid) an oly(acrylamide) through persulfate induced free radical initiated polymerization processes and covalent cross-linking of the prepared materials. Equilibrium sorption experiments were carried out at different pH and initial dye concentration values. The experimental equilibrium data for each adsorbent-dye system were fitted to the Langmuir-Freundlich adsorption isotherm, which provided adequate theoretical correlation (R-2 > 0 980). The grafting modifications greatly enhanced the adsorption performance of the biosorbents, especially in the case of powdered cross-linked chitosan grafted with acrylic acid, which exhibited a maximum adsorption capacity for Basic Yellow 37 (BY) equal to 832.0 mg/g. Kinetic Studies also revealed a significant improvement of sorption rates by the modifications. Furthermore, desorption experiments affirmed the regenerative capability of the loaded material.