Efficient adsorption and separation of dysprosium from NdFeB magnets in an acidic system by ion imprinted mesoporous silica sealed in a dialysis bag

A straightforward, one-pot approach for novel ion imprinted mesoporous silica materials (IMS) has been developed by co-condensation. IMS was used for the recovery of dysprosium through solid-liquid extraction in an acidic system. The dysprosium adsorption of IMS was efficiently modeled using a pseudo-second order rate equation. The initial kinetics of adsorption was fast, and almost complete adsorption was observed after 150 min. Adsorption isotherms were efficiently modeled using the Langmuir equation. The adsorption capacity of IMS toward dysprosium was 22.33 mg g^-1 at pH = 2.0, which was apparently greater than the adsorption capacity of non-imprinted materials at pH = 5.0. The value of the imprint factor at pH = 2.0 was higher than the other pH obviously. The distribution coefficient relative to dysprosium was 539 mL g^-1, which was significantly higher than that of other rare earth ions. IMS demonstrates enhanced selectivity towards dysprosium compared to non-imprinted materials in an acidic solution via solid-liquid extraction, which substantially improves the selective extraction process and provides a greener alternative to liquid-liquid extraction. In addition, the materials demonstrated a high degree of reusability over five extraction-stripping cycles, enhancing their potential for application in real rare earth metal recycling in acidic systems.