Synthesis of environmental-friendly ion-imprinted magnetic nanocomposite bentonite for selective recovery of aqueous Sc(III).

A novel reusable ion imprinted nanocomposite magnetic bentonite(IIPNMB) was prepared for selective recovery of aqueous scandium. Based on the fact that oxyphosphorus functional groups in sodium tripolyphosphate have good affinity to Sc(III) and chitosan is rich in hydroxy and amino active sites, they were chosen to build ion imprinted layers. Mesoporous IIPNMB showed good adsorption performance. The pseudo second-order kinetic model and Langmuir model fit the experimental data. According to XPS features, the amino, hydroxyl, PO and PO bonds of the adsorbents had electrostatic interaction and complexation with Sc(III), leading to the good selectivity of IIPNMB for Sc(III). In addition, the material atomic structure was proposed based on the chemical structure of IIPNMB for DFT calculation of ion imprinting adsorption, which clearly proved that the adsorption process of Sc(III) was stable, and it gave another proof for the mechanism of the selective extraction.