Hierarchical porous zeolitic imidazolate frameworks nanoparticles for efficient adsorption of rare-earth elements

Hierarchical porous zeolitic imidazolate frameworks nanoparticles (ZIF-8 NPs) were synthesized at room temperature via a template-free approach under dynamic conditions (stirring) using water as a solvent. The ZIF-8 NPs were evaluated as adsorbents for rare earth elements (La3+, Sm3+ and Dy3+). Adsorption equilibrium was reached after 7 h and high adsorption capacities were obtained for dysprosium and samarium (430.4 and 281.1 mg g−1, respectively) and moderate adsorption capacity for lanthanum (28.8 mg g−1) at a pH of 7.0. The high adsorption capacitiese, as well as the high stability of ZIF-8 NPs, make the hierarchical ZIF-8 materials as an efficient adsorbent for the recovery of La3+, Sm3+ and Dy3+ from aqueous solution.