Brewer Aaron, Florek Justyna, Kleitz Freddy
Department of Inorganic Chemistry - Functional Materials, Faculty of Chemistry, University of Vienna Währinger Strasse 42 1090 Vienna Austria
Green Chem. 2022 Mar 11;24(7):2752-2765. doi: 10.1039/d2gc00347c. eCollection 2022 Apr 4.
Critical materials (CMs) are a group of elements that have been determined to be important for the modern economy, but which may face current or potential supply limitations. Some examples of metals that have received the CM designation include the rare earth elements, indium, gallium, and lithium. The last decade has seen a major push for the development of new and improved technologies for the recovery and purification of CMs from various traditional and non-traditional resources in an effort to diversify supply. Solid-phase extraction (SPE) is one broad category of these experimental extraction technologies. SPE involves the application of a solid material to preferentially retain in the solid phase one or more specific components of an aqueous solution, leaving the other components behind in the aqueous phase. A wide range of different sorbents has been used for SPE, and many offer significant potential advantages, including low cost, low environmental impact, and high customizability. Hierarchically porous silica monoliths are one example of a cutting-edge sorbent that provides a durable, high surface area foundation that can be functionalized with a variety of targeted ligands for the selective extraction of specific CMs. Despite impressive recent advances in SPE, there remain areas for improvement that are common across the discipline. To demonstrate the practical viability of these innovative CM recovery systems, future SPE studies would benefit from devoting additional focus to the scalability of their material, as well as from focusing on real-world feedstocks and conducting techno-economic analyses and environmental impact studies.
关键材料（CMs）是一组已被确定对现代经济至关重要，但可能面临当前或潜在供应限制的元素。获得CM指定的金属示例包括稀土元素、铟、镓和锂。在过去十年中，人们大力推动开发新的和改进的技术，用于从各种传统和非传统资源中回收和提纯CMs，以实现供应多样化。固相萃取（SPE）是这些实验性萃取技术中的一大类。SPE涉及应用一种固体材料，优先在固相中保留水溶液中的一种或多种特定成分，而将其他成分留在水相中。已将多种不同的吸附剂用于SPE，许多吸附剂具有显著的潜在优势，包括低成本、低环境影响和高可定制性。分级多孔硅胶整体柱是一种前沿吸附剂的例子，它提供了一个耐用的、高表面积的基础，可以用各种靶向配体进行功能化，以选择性萃取特定的CMs。尽管最近SPE取得了令人瞩目的进展，但该学科仍存在一些普遍需要改进的领域。为了证明这些创新的CM回收系统的实际可行性，未来的SPE研究将受益于更多地关注其材料的可扩展性，以及关注实际原料并进行技术经济分析和环境影响研究。
