Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou 730070, China.
Lanzhou Ecological Environment Monitoring Center of Gansu Province, Lanzhou 730000, China.
Anal Chem. 2021 Jan 26;93(3):1732-1739. doi: 10.1021/acs.analchem.0c04407. Epub 2020 Dec 23.
Rare earth elements (REEs) are used widely in devices of many fields, but it is still a troublesome task to achieve their selective separation and purification. Metal-organic frameworks (MOFs) as an emerging porous crystalline material have been used for selective separation of REEs using the size-selective crystallization properties. However, so far, almost all MOFs cannot be used directly for selective separation of REEs in strong acid solid-state adsorption. Herein, a zinc-trimesic acid (Zn-BTC) MOF is grown by solid synthesis on ZnO nanoparticles covering nanoporous graphene for preparing Zn-BTC MOF/nanoporous graphene composites with strong acid resistance. The adsorption capacity of the resulting composites to REEs is highly sensitive to the ionic radius, which may be attributed to the fact that the REE ions coordinate with O to form a stable structure. The selectivity of Ce/Lu is ≈10,000, and it is extremely important that the selectivity between adjacent REEs (e.g., Nd/Pr) is as high as ≈9.8, so the composite exhibits the best separation performance so far. This work provides a green, facile, scale, and effective synthesis strategy of Zn-BTC MOF/nanoporous graphene, which is hopefully applied directly in the separation industries of REEs.
稀土元素（REEs）广泛应用于许多领域的设备中，但实现它们的选择性分离和纯化仍然是一项棘手的任务。金属有机骨架（MOFs）作为一种新兴的多孔晶体材料，已经被用于利用尺寸选择性结晶特性来选择性分离 REEs。然而，到目前为止，几乎所有的 MOFs 都不能直接用于强酸固态吸附中 REEs 的选择性分离。在此，通过固相结合方法在覆盖纳米多孔石墨烯的氧化锌纳米粒子上生长了锌-均苯三甲酸（Zn-BTC）MOF，用于制备具有耐强酸性能的 Zn-BTC MOF/纳米多孔石墨烯复合材料。所得复合材料对 REEs 的吸附容量对离子半径高度敏感，这可能是因为 REE 离子与 O 配位形成稳定的结构。Ce/Lu 的选择性约为 10000，相邻 REE 之间（如 Nd/Pr）的选择性高达约 9.8，因此该复合材料表现出迄今为止最好的分离性能。这项工作提供了一种绿色、简便、规模化、有效的 Zn-BTC MOF/纳米多孔石墨烯的合成策略，有望直接应用于 REEs 的分离工业。
