Portable Luminescent Sensing Technologies for Economically Critical Metal Ions

S. Crawford, J. Baltrus, K-J Kim, N. Diemler
National Energy Technology Laboratory/Leidos,
United States

Keywords: rare earth elements, cobalt, aluminum, critical metals, luminescent sensors


The increasing global adoption of renewable energy technologies such as electric vehicles and wind power, which are heavily reliant upon metals, has lead to widespread concerns about the stability of the supply chain for these metals. A range of strategies have been developed to boost domestic production for economically critical metals, including conventional methods such as mining as well as unconventional methods such as extraction from waste produces including coal utilization byproducts. However, slow and expensive techniques for metals characterization remain a significant barrier for metals prospecting and processing. This presentation describes the integration of different critical metal ion-specific sensing materials with a low-cost, portable fiber optic probe, enabling rapid detection of individual metal elements in environmentally-relevant conditions, such as low pH and high ionic strength. This probe was integrated with different sensing materials for highly sensitive detection of several rare earth elements, cobalt, and aluminum, which are all considered economically critical. Parts-per-billion levels of terbium, europium, samarium, and dysprosium were detected in aqueous streams and in several ash leachate samples using luminescent zinc adeninate metal-organic frameworks as the sensing material. Similarly, thin films comprised of copper and 2-aminoterephthalate were developed to selectively detect parts-per-billion levels of aluminum(III) ions, while the sensitive detection of cobalt at low parts-per-million concentrations was achieved using an inexpensive carbon nanodot material. Taken together, these results highlight the tremendous potential for developing inexpensive and fully portable optical sensors to rapidly and sensitively characterize specific economically critical metals.