Iordache Andreea Maria, Nasture Ana Maria, Zgavarogea Ramona, Andrei Radu, Mandoc Roxana, Feizula Erdin, Santos Rui, Nechita Constantin
ICSI Analytics Department, National Research and Development Institute for Cryogenics and Isotopic Technologies-ICSI, 4 Uzinei Street, 240050 Râmnicu Vâlcea, Romania.
ICSI Energy Department, National Research and Development Institute for Cryogenics and Isotopic Technologies-ICSI, 4 Uzinei Street, 240050 Râmnicu Vâlcea, Romania.
Materials (Basel). 2025 Apr 29;18(9):2016. doi: 10.3390/ma18092016.
The enrichment of Li isotopes from a natural stage of 7.6% to above 59% is required for the development of next-generation green technologies capable of sustaining climate change mitigation and energy-mix targets. In this study, we developed two categories of custom laboratory-made organic membranes, membranes that were non-impregnated before electromigration (AI-1) and membranes impregnated with LiNT (AI-2), to evaluate their performance in lithium isotope separation. Both types of membranes were exposed in synthesis to ionic liquid and crown ether. The objective of the study was to test the performance of membranes in separating lithium isotopes from a lithium-loaded organic phase in an aqueous solution with variable potentials and time intervals. The results show that the impregnated AI-2 membranes increased the enrichment of Li in the early stages, and the effect decreased after 25 h. The efficiency of lithium isotope enrichment was positively related to the potential profile applied, migration time, and concentration of organic solution in the anode chamber. The 0.5 mol/L Bis-(trifluoromethane) sulfonimide lithium salt (Li[NT]) with 0.1 M tetra butyl ammonium perchlorate (TBAP) in acetonitrile (CHCN) ionic solution significantly improved Li isotope separation compared with an aqueous environment with higher salt concentrations. The maximum isotopic separation coefficient (α) for AI-1.2 (15-crown-5 ether and 1 mol/L LiNT in TBAP solution after 48 h of electromigration) gradually increased to 1.0317. Our results demonstrated that in the laboratory-made setup described, the migration efficiency and Li isotope separation in the catholyte environment needed a minimum of 9 V and a migration time of 6 h, respectively; these values varied with the concentration of the organic solution in the anode chamber. The ability of laboratory-engineered membranes to impart isotope selectivity and enhance permselectivity or selectivity towards singly charged ions was demonstrated through the functionality of single-collector inductively coupled plasma mass spectrometry (ICP-MS). This technology is particularly valuable and commercially feasible for future lithium isotope research in nuclear technology.
为了开发能够实现缓解气候变化和能源结构目标的下一代绿色技术，需要将锂同位素从7.6%的天然丰度富集到59%以上。在本研究中，我们开发了两类定制的实验室自制有机膜，即电迁移前未浸渍的膜（AI-1）和浸渍有LiNT的膜（AI-2），以评估它们在锂同位素分离中的性能。两种类型的膜在合成过程中都暴露于离子液体和冠醚中。该研究的目的是测试膜在可变电位和时间间隔下从水溶液中的载锂有机相中分离锂同位素的性能。结果表明，浸渍的AI-2膜在早期阶段提高了锂的富集度，25小时后效果下降。锂同位素富集效率与施加的电位分布、迁移时间和阳极室中有机溶液的浓度呈正相关。与盐浓度较高的水性环境相比，在乙腈（CHCN）离子溶液中含有0.1 M高氯酸四丁基铵（TBAP）的0.5 mol/L双（三氟甲烷）磺酰亚胺锂盐（Li[NT]）显著改善了锂同位素分离。AI-1.2（电迁移48小时后在TBAP溶液中的15-冠-5醚和1 mol/L LiNT）的最大同位素分离系数（α）逐渐增加到1.0317。我们的结果表明，在所描述的实验室自制装置中，阴极电解液环境中的迁移效率和锂同位素分离分别至少需要9 V的电压和6小时的迁移时间；这些值随阳极室中有机溶液的浓度而变化。通过单收集器电感耦合等离子体质谱（ICP-MS）的功能，证明了实验室工程膜赋予同位素选择性并增强对单电荷离子的渗透选择性或选择性的能力。这项技术对于未来核技术中的锂同位素研究特别有价值且在商业上可行。
