Preparation of ion-imprinted montmorillonite nanosheets/chitosan gel beads for selective recovery of Cu(Ⅱ) from wastewater.

The novel ion-imprinted montmorillonite nanosheets/chitosan (IIMNC) gel beads were prepared for selective adsorption of Cu2+. The IIMNC gel beads were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results showed that IIMNC was successfully assembled and rich in honeycombed pores, which performed well in the removal of Cu2+ through the synergistic effect of montmorillonite nanosheets and chitosan. The elimination of copper was followed by pseudo-second-order model and was enhanced by introduced montmorillonite nanosheets (MMTNS) because MMTNS attracted Cu(Ⅱ) by its negative charge and provided active adsorption sites through its high performance of cation exchange. This composite gel also showed excellent reusability, performing well in the removal of Cu2+ after undergoing adsorption-desorption in five cycles, because the adsorption sites of MMTNS can be continually reactivated by NaOH solution. More importantly, its high selectivity for Cu2+ provides a feasible way to recover Cu2+ from wastewater containing various cations.