Novel material innovations for the efficient extraction and separation of critical elements

Critical materials (CMs) are essential for the modern economy but face challenges due to current or potential supply shortages. Notable examples include scandium (Sc), rare earth elements (REEs), indium (In), and gallium (Ga). Recovering REEs often requires their separation from Thorium (Th) and Uranium (U), which are commonly found together in various feedstocks. Given the value of these elements, as well as the critical role of other metals like Sc, In, and Ga in technology, the development of advanced materials and innovative strategies for their sustainable recovery is crucial. Solid-phase extraction (SPE) represents a versatile approach within experimental extraction technologies. Silica-based materials, with tunable surface properties and good stability, excel as sorbents for these applications. This presentation highlights ligand-functionalized SBA-15, which demonstrated remarkable selectivity for Th at pH 2, even with competing elements (REEs, Al, Fe), and efficiently extracted Sc and U at pH 4, showcasing its dual functionality. It also efficiently recovered In from model solutions simulating semiconductor materials and separated In from Sn in solutions mimicking ITO (indium tin oxide) films compositions. Additionally, bare SBA-15 exhibited strong selectivity for Ga in model solutions replicating semiconductor substrates and effectively separated Ga from Al, showcasing its versatility and efficiency.