S. Crawford, J. Ellis, J. Baltrus
Leidos-National Energy Technology Laboratory,
Keywords: rare earth elements, sensors, lanthanides
Summary:Rare earth elements (REEs) are a crucial for many advanced technologies, particularly those related to renewable energy, where they are used extensively in wind power turbines and electric vehicles. While demand for REEs is anticipated to grow significantly in coming decades, the REE supply is restricted by a monopolistic global marketplace, tedious and costly processing steps for REE production, and environmental hazards associated with mining and extraction. Coal and coal-utilization byproducts have emerged as potential domestic sources for REEs, however REE production from these sources is currently hindered by slow and expensive characterization techniques. Here, we demonstrate that metal-organic framework (MOF)-based sensitizers can rapidly detect and distinguish part-per-billion concentration levels of emissive REEs, including terbium, europium, dysprosium, samarium, neodymium, and ytterbium. Importantly, we demonstrate that the MOF structure is crucial for selective REE detection under acidic conditions, an essential step towards sensor deployment in various REE-rich process streams. As a proof-of-concept, we demonstrate detection of REEs in spiked acid mine drainage systems, and integration of MOF materials with portable instrumentation for field deployment.