Larrinaga Wyatt B, Lake Bailey J, Pacanowski Victoria D, Patterson Michael G, Hudson Michael, Carlson Faith M, Heselschwerdt Gabriel, Balboa Steven, Biros Shannon M, Werner Eric J
Department of Chemistry and Biochemistry, The University of Tampa, 401 West Kennedy Boulevard, Tampa, Florida 33606, United States.
Department of Chemistry, Grand Valley State University, 1 Campus Drive, Allendale, Michigan 49401, United States.
Inorg Chem. 2024 Jul 29;63(30):13815-13819. doi: 10.1021/acs.inorgchem.4c01240. Epub 2024 Jul 17.
One of the major challenges in processing rare-earth element (REE) materials arises from the large amounts of radioactive thorium (Th) that are often found within REE minerals, encouraging enhanced metal separation procedures. We report here a study aimed at developing improved systems for REE processing with the goal of efficient extraction of Th(IV) from acidic solution. A tripodal ligand, TRPN-CMPO-Ph, was prepared that utilizes carbamoylmethylphosphine oxide (CMPO) chelators tethered to a tris(3-aminopropyl)amine (TRPN) capping scaffold. The ligand and its metal complexes were characterized by using elemental analysis, NMR, Fourier transform infrared spectroscopy, mass spectrometry, and luminescence spectroscopy. Using a liquid-liquid metal extraction protocol, TRPN-CMPO-Ph selectively extracts Th(IV) at an efficiency of 79% from a mixture of Th(IV), UO, and all rare-earth metal cations (except promethium) dissolved in nitric acid into an organic solvent. Th(IV) extraction selectivity is maintained upon extraction from a mixture that approximates a typical monazite leach solution containing several relevant lanthanide ions, including two ions at higher concentration relative to Th(IV). Comparative studies with a tris(2-aminoethyl)amine (TREN)-capped derivative are presented and support the need for a larger TRPN capping scaffold in achieving Th(IV) extraction selectivity.
处理稀土元素（REE）材料的主要挑战之一源于稀土矿物中常常存在的大量放射性钍（Th），这促使人们改进金属分离程序。我们在此报告一项旨在开发改进的稀土处理系统的研究，目标是从酸性溶液中高效萃取Th(IV)。制备了一种三脚架配体TRPN-CMPO-Ph，它利用与三（3-氨丙基）胺（TRPN）封端支架相连的氨甲酰甲基氧化膦（CMPO）螯合剂。通过元素分析、核磁共振、傅里叶变换红外光谱、质谱和发光光谱对该配体及其金属配合物进行了表征。使用液-液金属萃取方法，TRPN-CMPO-Ph从溶解在硝酸中的Th(IV)、UO以及所有稀土金属阳离子（除钷外）的混合物中，以79%的效率选择性地将Th(IV)萃取到有机溶剂中。从近似典型独居石浸出溶液的混合物（包含几种相关镧系离子，包括相对于Th(IV)浓度较高的两种离子）中萃取时，Th(IV)的萃取选择性得以保持。文中还展示了与三（2-氨乙基）胺（TREN）封端衍生物的对比研究，支持了需要更大的TRPN封端支架来实现Th(IV)萃取选择性的观点。
