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.