Dual-template docking oriented ionic imprinted bilayer mesoporous films with efficient recovery of neodymium and dysprosium

Highlights: • Ionic imprinted mesoporous bilayer films (IIBFs) were prepared by dual-template docking oriented ionic imprinting (DTD-OII). • DTD-OII do not require additional steps compare with traditional imprinting. • IIBFs exhibited high selective adsorption of neodymium and dysprosium. • IIBFs can staged stripping of neodymium and dysprosium by control of temperature. - Abstract: Rare earth elements (REEs) are critical materials to many cutting-edge technologies but are difficult to separate from one another because of their chemical similarity. We present ionic imprinted mesoporous bilayer films (IIBFs) as an ideal adsorbent for selective separation of neodymium (Nd) and dysprosium (Dy) from sintered neodymium magnets. IIBFs were prepared according to dual-template docking oriented ionic imprinting (DTD-OII). Due to different imprinted compositions of bilayer films, IIBFs exhibited high specific surface area, fast binding equilibrium, and Janus properties for simultaneous selective adsorption of different rare earth ions, which made our imprinted bilayer mesoporous films a specialized adsorbent for adsorption of Nd(III) and Dy(III) at the same time. The adsorption capacities of optimized IIBFs were 17.50 mg g⁻¹ for Dy(III) and 12.15 mg g⁻¹ for Nd(III) at pH = 4.0. Moreover, we grafted thermo-responsive polymer on the one surface of IIBFs to realize controlled release of Nd(III) and Dy(III) by temperature. IIBFs demonstrate a high degree of reusability by cycling experiments by DTD-OII, which develop their promising applications for the REE recycling and separation industry.