A ion-imprinted chitosan/Al₂O₃ composite material for selective separation of copper(II)

Abstract

A novel copper(II) ion-imprinted chitosan/aluminum oxide (IIP/Al₂O₃) has been prepared with the surface-grafted and surface imprinting technologies for selective adsorption of Cu(II) from aqueous solutions. Al₂O₃ powder, modified with tetraethyl orthosilicate, was used as the carrier material. Chitosan was employed as the functional monomer. The prepared IIP/Al₂O₃ was characterized by using the infrared spectra, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Effects of pH and initial concentration of Cu(II) on the adsorption capacity of IIP/Al₂O₃ were investigated, and the adsorption kinetics and thermodynamics were also studied. Results showed that, the kinetic data were fitted well by the pseudo-second-order model. The adsorption equilibrium data were fitted well by the Langmuir isotherm model. The thermodynamic parameters indicated that the adsorption of Cu(II) on IIP/Al₂O₃ was an endothermic and spontaneous process. Further, the selectivity experiment was done for the mixed solutions containing Cu(II), Ni(II), and Zn(II). The selectivity factors of Cu(II) on IIP/Al₂O₃ were much higher than those of Ni(II) and Zn(II). After Cu(II) adsorption-desorption cycles were repeated 10 times by using the same IIP/Al₂O₃, the adsorption capacity of IIP/Al₂O₃ was decreased only 2%. The IIP/Al₂O₃ showed good stability and reusable properties.

Keywords:

• Surface ion-imprinted
• Adsorption
• Copper(II)
• Aluminum oxide
• Selective separation

Acknowledgments

This research is supported by the Hunan Provincial Natural Science Foundation of China (No. 13JJ3086). Also, the authors acknowledge the financial supports from a Project Supported by the National Natural Science Foundation of China (No. 20976040).