CAS-SC: Thermally Switchable Organic Solvents for Targeted Harvesting of Lithium Ions from Alkali Metal Cations Mixtures in Hypersaline Brines

开发新技术以更有效和可持续地从非常规来源提取锂，将使国内锂资源的生产和再利用成为可能。锂可以在地热盐水和其他非常规来源中找到，如石油和天然气生产废物流。然而，这些盐水中的锂离子浓度远低于其他离子，如钠，钾和镁。从这些盐水中分离锂是具有挑战性的，因为锂在化学上与其他碱金属阳离子相似，包括钠和钾。该项目旨在推进从盐水中提取锂离子的可持续化学方法。该项目将产生多项有益成果，包括开发节能工艺，从废物中回收和再循环关键矿物，提高大规模分离方法的效率，更有效地利用可再生能源来推动分离工艺，以及寻找依赖昂贵和有毒化学品的工艺的可持续替代品。这些锂分离技术的进步将对能源安全产生变革性影响，增加传统来源的锂产量，从非传统来源释放锂资源，并使现有锂的回收和再利用更具经济可行性。此外，该项目还包括教育和研究部分，以培训和准备高中，本科和研究生STEM科目。该项目旨在了解离子选择性卤水开采的可切换溶剂萃取的基本控制现象。本研究将物理化学热力学原理与本体相实验表征相结合，以提高离子的选择性分离。具体的项目目标是：1）建立控制可转换溶剂和高盐盐水两相混合物中竞争性分配行为的主要离子特性，2）确定内在溶剂结构-特性关系和离子特异性选择性性能，以及3）制定一个严格的物理化学框架，用于先验确定多组分两相系统中的离子活度系数。本研究计划将系统地阐明油溶剂和多电解质盐水两相体系中离子优先分配的基本机制。这些机理见解将为未来的直接锂提取技术进步提供信息。该项目的教育活动包括（i）开发K-12教育和公共宣传模块，（ii）加强本科生和研究生课程，（iii）提供本科生研究机会，以及（iv）积极招聘，指导，该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值进行评估来支持和更广泛的影响审查标准。

Developing new technologies to extract lithium from unconventional sources more efficiently and sustainably will enable the production and reuse of domestic lithium resources. Lithium can be found in geothermal brines and other unconventional sources such as oil and gas production waste streams. However, the lithium-ion concentration in these brines is much lower than other ions like sodium, potassium, and magnesium. Separating lithium from these brines is challenging because lithium is chemically similar to other alkali metal cations, including sodium and potassium. This project aims to advance a sustainable chemistry-based approach for extracting lithium ions from aqueous brines. The project will have several beneficial outcomes, including developing energy-efficient processes to recover and recycle critical minerals from waste, improving the efficiency of at-scale separation methods, using renewable energy more efficiently to drive separation processes, and finding sustainable alternatives to processes that rely on expensive and toxic chemicals. These advancements in lithium separation will have a transformative effect on energy security by increasing lithium production from conventional sources, unlocking lithium resources from unconventional sources, and making the recycling and reuse of existing lithium more economically viable. Additionally, the project includes educational and research components to train and prepare high school, undergraduate, and graduate students in STEM subjects.This project aims to understand the fundamental governing phenomena in switchable solvent extraction for ion-selective brine mining. The research integrates physical chemistry thermodynamic principles with bulk-phase experimental characterizations to improve selective ion separations. The specific project objectives are to: 1) establish the principal ion properties governing competitive partitioning behavior in biphasic mixtures of switchable solvents and hypersaline brines, 2) determine the intrinsic solvent structure-property relationship and ion-specific selectivity performance, and 3) formulate a thermodynamically-rigorous physical chemistry framework for a priori determination of ion activity coefficients in multicomponent biphasic systems. The research plan will systematically elucidate the underlying mechanisms of preferential ion partitioning in biphasic systems of oleo-solvents and multi-electrolyte aqueous brines. These mechanistic insights will inform future direct lithium extraction technology advancements. The project’s educational activities include (i) developing modules for K–12 education and public outreach, (ii) enhancing undergraduate and graduate courses, (iii) providing undergraduate research opportunities, and (iv) actively recruiting, mentoring, and advocating for underrepresented groups in STEM.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.