Enhanced Selective Adsorption of Rare Earth Ions with Ion-Imprinted Poly(hydroxamic acid) Interpenetrating Polymer Networks: Fabrication, Performance, and Mechanisms

The separation of rare earth elements (REEs) is challenging due to their similar chemical properties. This study developed a series of novel polystyrene–ion-imprinted poly(hydroxamic acid) interpenetrating polymer networks (PS-IIPHAs) for the highly selective adsorption of La3+, Ce3+, and Y3+. The effects of the solution pH, contact time, initial concentrations, and temperature on the adsorption performance of the resins were systematically investigated. The results showed that adsorption equilibrium was reached within 4 h at a pH of 1.0, following the Langmuir isotherm, with maximum adsorption capacities of 2.425, 3.012, and 2.927 mmol/g for La3+, Ce3+, and Y3+, respectively. The resins exhibited excellent selectivity toward the template ions, with separation factors of 35.45 for Ce3+-La3+, 17.52 for Y3+-La3+, and 11.04 for Ce3+-Y3+. These results indicate PS-IIPHAs as promising adsorbents for the efficient, highly selective recovery of REEs.