Collaborative Research: DMREF: Rational design of redox-responsive materials for critical element separations

非技术描述：稀土元素和铂族金属是智能手机、发光二极管（LED）灯和绿色能源技术等应用的关键元素。其他国家开采和加工了世界上大部分稀土供应。美国的稀土矿占全球稀土元素年供应量的15%。然而，美国的矿山生产的是这些元素的混合物，在它们彼此分离之前，它们不能用于应用。该项目将制定从废物流中分离和回收稀土元素和铂族金属的可持续战略。该项目将利用电动分离装置分离这些有价值的元素。这种方法是模块化的，可逆的，最大限度地减少浪费，并且可以由可再生能源驱动。结合这些元素的电极材料将从导电聚合物和碳纳米管中开发出来。除了为关键材料经济做出贡献之外，所获得的知识还可以应用于其他具有挑战性的分离，例如从水中去除重金属和有毒污染物。该项目还将有助于教育和培养在数据科学、计算和实验方面具有关键能力的多元化未来劳动力。将发布新的教育内容，对学生进行高级材料主题的培训，并实施K-12外展计划。技术描述：电化学电荷转移材料已被提出作为分离过程的新一代技术，包括海水淡化、关键元素回收和有毒污染物的修复。电力驱动系统具有显著的优势，如与可再生能源集成，消除二次污染物或再生化学品，仅通过电化学可再生，以及模块化。然而，铂族金属（PGMs）和稀土元素（ree）的回收对分离科学来说是一个重大挑战，因为这些元素在存在过量竞争物种的情况下被发现为稀释离子，并且根据pH和离子浓度具有复杂的物种形成，并且电分离对稀土和PGMs的适用性受到分子选择性的基本缺乏的严重限制。该项目将通过发现具有创新吸附-离子相互作用模式的新型聚合物基电极材料，提供高选择性且可逆的结合，开发和实施有效的稀土和PGM回收电化学系统。虽然典型的设计方法采用储能材料或使用试错法，但经过分子动力学（MD）模拟和实验数据训练的机器学习（ML）将指导化学选择、合成和电极墨水创建，以生产离子选择性且可加工的氧化还原聚合物。在闭环中同时设计分子结合和聚合物二级结构有助于加速先进氧化还原材料的下游部署。md引导的聚合物骨架和溶剂的选择，最大限度地提高了油墨的稳定性，加上先进的流变学和涂层工艺，将能够通过放大，克服氧化还原聚合物的溶解度和加工挑战，创造出具有理想宏观性能的电吸附剂。计算和实验之间的迭代将产生一个合理设计氧化还原电极的框架，除了解决与采矿和关键材料回收直接相关的关键元素混合物外，还可以扩展到解决海水淡化和环境修复中的挑战。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。

Non-technical Description: Rare-earth elements and platinum group metals are critical elements for applications ranging from smartphones and light-emitting-diode (LED) lights to green energy technologies. Other countries mine and process most of the world’s REE supply. US mines can contribute to 15% of the world’s annual supply of rare-earth elements. However, US mines produce mixtures of these elements, which cannot be used in applications until they are separated from one another. This program will develop sustainable strategies for separating and recovering rare-earth elements and platinum group metals from waste streams. This project will utilize electrically-driven separations to separate these valuable elements. This approach is modular, reversible, minimize waste, and can be driven by renewable sources. Electrode materials that bind these elements will be developed from conductive polymers and carbon nanotubes. Beyond contributing to the critical materials economy, the knowledge gained can be applied to other challenging separations, like removing heavy metals and toxic contaminants from water. This project will also help educate and cultivate a diverse future workforce with key competencies in data science, computation, and experiments. New educational content will be released, students will be trained on advanced materials topics, and K-12 outreach programs will be implemented. Technical Description: Electrochemical charge-transfer materials have been proposed as new-generation technologies for separation processes, including water desalination, critical element recovery, and remediation of toxic contaminants. Electrically-driven systems offer significant advantages such as integration with renewable energy, elimination of secondary pollutants or regeneration chemicals by being solely electrochemically regenerable, and modularity. However, recovery of platinum group metals (PGMs) and rare-earth elements (REEs) is a significant challenge for separations science because these elements are found as dilute ions in the presence of excess levels of competing species and with complex speciation depending on pH and ion concentration – and the applicability of electroseparations to REEs and PGMs is severely limited by the fundamental lack of molecular selectivity. This program will develop and implement efficient electrochemical systems for REE and PGM recovery by discovering new polymer-based electrode materials with innovative adsorbate–ion interaction modes, which provide highly selective yet reversible binding. Though typical design approaches employ energy storage materials or use trial­and­error, where machine learning (ML) trained on molecular dynamics (MD) simulations and experimental data will guide chemical selection, synthesis, and electrode ink creation to produce ion-selective yet processable redox­polymers. The simultaneous design of molecular binding and polymer secondary structure in a closed­loop can help accelerate downstream deployment of advanced redox­materials. MD­guided selection of polymer backbones and solvents that maximize ink stability, paired with advanced rheology and coating processes, will enable the creation of electrosorbents with desired macroscopic properties through scaleup, overcoming solubility and processing challenges typical of redox­polymers. Iteration between computation and experiments will produce a framework for rationally designing redox electrodes that, in addition to addressing critical element mixtures of direct relevance to mining and critical materials recycling, can be extended to address challenges in water desalination and environmental remediation.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.