Cross-linking copolymerization on magnetic microspheres surface induced neodymium ion imprinting for high capacity and high selectivity removal of Nd3+ from aqueous solution

Abstract

The development of reliable ways to recover rare earth metals can avoid the loss of valuable resources in tailings, industrial wastewater and process residues. In this study, 2-acetamidoacrylic acid, which has a strong coordination ability for Nd3+, was selected as the functional monomer through theoretical simulation (DFT calculation) and experimental study (fluorescence burst method). Meanwhile, Nd3+ was used as template ion, N-isopropylacrylamide as an ionic cross-linker, ethylene glycol dimethacrylate was used as cross-linking agent, Fe3O4@SiO2 was used as carrier, and ion imprinted polymer containing Nd3+ vacancy (Nd(III)-V/MIIP) was synthesized by surface imprinting technique. The Nd(III)-V/MIIP prepared by this method can selectively adsorb Nd3+ in various metal ion solutions, and the adsorption capacity was increased by about 40 % compared with that of the MNIP adsorbent without Nd3+ vacancies, with a distribution system of 624.93 mL/g. The Nd(III)-V/MIIP can effectively solve the problem of the difficult separation of the rare earth ions from each other. Based on the results of XPS, DFT, HOMO and LUMO, it can be inferred that −COO− coordination on AAA, where the −COO− is coordinated to Nd3+ with a binding energy of -26.58 eV, which allows selective adsorption of Nd3+ ions in the complex water system.