Fe3O4ベースの機能化コアシェル磁性ナノ材料を用いた希土類吸着および回収の最近の進歩：課題と展望

This review systematically summarizes recent advances regarding the use of Fe₃O₄-based functionalized core-shell magnetic nanomaterials (Fe₃O₄-based FCMNs) for adsorbing and recovering rare earth elements (REEs)-a practice pivotal to resource conservation, recycling, and sustainable management. As non-renewable critical resources, REEs' efficient recovery aligns with goals of reducing reliance on primary extraction and minimizing resource waste. Fe₃O₄, the widely used magnetic core, is favored for strong magnetic response, simple synthesis, low toxicity, and affordability-traits that lower the environmental and economic costs of REEs recovery, which is vital for long-term resource utilization. Its preparation methods shape properties key to practical application in resource systems. Functionalized shells (polymers, silica-based, carbon-based, MOFs/COFs, etc.) enable REEs adsorption via functional groups and specific mechanisms, directly advancing resource recovery efficiency. This review examines several key aspects: the construction of core-shell structures, the underlying adsorption mechanisms, and the performance of various shell materials. It also addresses practical challenges-such as secondary pollution and performance decline during reuse-that could undermine sustainable practices. Finally, it outlines future priorities, including the separation of light/heavy REEs, in-situ solidification, and stability in complex environments, to improve the suitability of these materials for large-scale recycling. This work offers a comprehensive overview of Fe₃O₄-based FCMNs in REE recovery, aiding advancements that bolster sustainable REEs management and protection.