Hybrid Strategy for In Situ Shaping of Zeolite‐Imidazolate‐Frameworks into Polymeric Macrocapsule: Toward Practical Applications of Rare Earth Element Recovery

Abstract

AbstractThe efficient recovery of rare earth elements (REEs) from secondary sources is an urgent global challenge. Although zeolite‐imidazolate‐framework‐8 (ZIF‐8) has unique advantages for REE recovery, its nanopowder form poses a significant obstacle to its practical application. Herein, the study proposes a novel in situ strategy for shaping ZIF‐8 into hierarchical 3D center‐radial channels of a polymeric macrocapsule (PMC) via a hybrid approach. Core–shell‐type ZIF‐8‐PMC hybrids (ZIF‐8@PMC) with the intrinsic physicochemical properties of ZIF‐8 are synthesized by combining counter‐diffusion‐based in situ growth and phase transformation, enabling unprecedented REE recovery of 463.6 and 580 mg g−1 for Nd3+ and Dy3+, respectively, which are superior to that of traditional encapsulating protocols. Moreover, ZIF‐8@PMC exhibits good applicability in the simulated permanent magnet leachate with recovery efficiencies of 92.5% (Nd3+) and 81.8% (Dy3+), after five repetitive cycles because of its protective nanoporous shell layer that prevents the release of in situ‐shaped ZIF‐8 to the exterior and invasion of external particulates into the PMC. Overall, these findings demonstrate the suitability of PMC as an ideal platform for the in situ shaping of ZIF‐8 and the application of the newly proposed protocol as a promising approach to expand the applicability of ZIF‐8 in various fields.