苏州大学王殳凹团队报道了镧系元素中Am（VI）-多金属氧酸盐的超滤分离。相关研究成果于2023年4月19日发表于国际顶尖学术期刊《自然》。

从用过的存在的镧系元素（Ln）的核燃料中分离镅在核能的可持续发展中发挥着关键作用。这项任务极具挑战性，因为热力学稳定的Am（III）和Ln（III）离子具有几乎相同的离子半径和配位化学性质。Am（III）氧化为Am（VI）会产生与Ln（III）离子不同的AmO₂²⁺离子，原则上有可能促进分离。然而，传统分离方案（包括溶剂和固体萃取）所需的辐解产物和有机试剂将Am（VI）快速还原回Am（III）阻碍了实际的基于氧化还原的分离。

该文中，研究人员报道了一种纳米级多金属氧酸盐（POM）簇，其具有与六价锕系元素（²³⁸U、²³⁷Np、²⁴²Pu和²⁴³Am）在硝酸介质中相对于三价镧系元素的选择性配位相容的空位。据研究人员所知，该团簇是迄今为止在水性介质中观察到的最稳定的Am（VI）物种。通过市售的细孔膜从水合镧系离子中分离纳米级Am（VI）-POM团簇，使得能够开发出高效快速、不涉及任何有机成分并且需要最小能量输入的一次性镅/镧系分离策略。

附：英文原文

Title: Ultrafiltration separation of Am(VI)-polyoxometalate from lanthanides

Author: Zhang, Hailong, Li, Ao, Li, Kai, Wang, Zhipeng, Xu, Xiaocheng, Wang, Yaxing, Sheridan, Matthew V., Hu, Han-Shi, Xu, Chao, Alekseev, Evgeny V., Zhang, Zhenyi, Yan, Pu, Cao, Kecheng, Chai, Zhifang, Albrecht-Schnzart, Thomas E., Wang, Shuao

Issue&Volume: 2023-04-19

Abstract: Partitioning of americium from lanthanides (Ln) present in used nuclear fuel plays a key role in the sustainable development of nuclear energy1,2,3. This task is extremely challenging because thermodynamically stable Am(III) and Ln(III) ions have nearly identical ionic radii and coordination chemistry. Oxidization of Am(III) to Am(VI) produces AmO22+ ions distinct with Ln(III) ions, which has the potential to facilitate separations in principle. However, the rapid reduction of Am(VI) back to Am(III) by radiolysis products and organic reagents required for the traditional separation protocols including solvent and solid extractions hampers practical redox-based separations. Herein, we report a nanoscale polyoxometalate (POM) cluster with a vacancy site compatible with the selective coordination of hexavalent actinides (238U, 237Np, 242Pu and 243Am) over trivalent lanthanides in nitric acid media. To our knowledge, this cluster is the most stable Am(VI) species in aqueous media observed so far. Ultrafiltration-based separation of nanoscale Am(VI)-POM clusters from hydrated lanthanide ions by commercially available, fine-pored membranes enables the development of a once-through americium/lanthanide separation strategy that is highly efficient and rapid, does not involve any organic components and requires minimal energy input.

DOI: 10.1038/s41586-023-05840-z

Source: https://www.nature.com/articles/s41586-023-05840-z