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，以更有效和可持续的方式从非常规资源中提取锂，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资源中找到，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钠、钾和镁等其他离子。从这些盐水中分离锂是一项挑战，因为锂的化学性质与其他碱金属阳离子（包括钠和钾）相似。该项目旨在推进一种基于可持续化学的方法，从盐水中提取锂离子。该项目将产生几个有益的结果，包括开发从废物中回收和循环利用关键矿物的节能工艺，提高大规模分离方法的效率，更有效地利用可再生能源推动分离过程，以及找到依赖昂贵和有毒化学品的工艺的可持续替代品。锂分离技术的这些进步将对能源安全产生变革性的影响，增加常规来源的锂产量，释放非常规来源的锂资源，并使现有锂的回收和再利用在经济上更加可行。此外，该项目还包括教育和研究部分，以培训和准备高中、本科生和研究生的STEM科目。本项目旨在了解离子选择性卤水开采中可切换溶剂萃取的基本控制现象。该研究将物理化学热力学原理与体相实验表征相结合，以提高选择性离子分离。具体的项目目标是：1)建立控制可切换溶剂和高盐盐水双相混合物中竞争分配行为的主要离子性质；2)确定固有的溶剂结构-性质关系和离子特异性选择性性能；3)制定一个热力学严格的物理化学框架，用于先验地确定多组分双相体系中的离子活度系数。本研究计划将系统地阐明油溶剂和多电解质水溶液双相体系中优先离子分配的潜在机制。这些机制的洞察将为未来直接锂提取技术的进步提供信息。该项目的教育活动包括(i)为K-12教育和公众宣传开发模块，（ii）加强本科和研究生课程，（iii）提供本科生研究机会，以及（iv）积极招募，指导和倡导STEM中代表性不足的群体。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.