Portable Luminescence Based Fiber Optic Probe for REE Detection and Quantification

Influence of the Anionic Zinc-Adeninate Metal–Organic Framework Structure on the Luminescent Detection of Rare Earth Ions in Aqueous Streams

“…Due to their unique physical and chemical properties, rare earth elements (REEs) are crucial to many advanced technologies, including catalysts, glassmaking, electric vehicle batteries, turbines, electronics, lighting displays, and other devices critical to sectors such as energy and national defense. − Despite their importance, the REE supply chain is unstable due to a combination of monopolistic global economic conditions and high financial and environmental costs associated with REE mining and processing. ,,, Consequently, there is a growing interest in producing REEs from alternative sources, such as electronic waste, coal utilization byproduct streams, − and industrial wastewaters . Rapid, inexpensive, and sensitive REE characterization techniques are needed both for resource exploration [e.g., locating REE-rich liquid streams such as acid mine drainage (AMD)] , and for characterizing downstream REE production steps, including the separation, purification, and concentration steps during REE processing. For example, scaled-up facilities have been developed, in which a series of solvent, acid/base, or bio-based , extraction and precipitation steps are used to isolate REEs from coal, , coal ash, ,, and AMD, , and high-performance analytical methods can be deployed to evaluate the efficiency of and make real-time adjustments to each production step.…”

“…For example, scaled-up facilities have been developed, in which a series of solvent, acid/base, or bio-based , extraction and precipitation steps are used to isolate REEs from coal, , coal ash, ,, and AMD, , and high-performance analytical methods can be deployed to evaluate the efficiency of and make real-time adjustments to each production step. In particular, portable luminescence-based sensors are attractive because they offer up to 1000× higher sensitivity than competing portable techniques (e.g., X-ray fluorescence and laser-induced breakdown spectrometers) for REEs while providing significantly lower equipment and operating costs relative to inductively coupled plasma mass spectrometry, a nonportable technique. ,, Several of the REEs in particular are well suited for luminescence-based sensing techniques because they exhibit distinct, element-specific emission bands in the visible and near-infrared regions; these bands arise from f-orbital transitions that are shielded by the outer s- and p-orbitals, yielding narrow, line-like emission bands. − However, these transitions are parity forbidden, leading to poor absorption and inefficient direct excitation . Hence, REE emission is typically induced via the use of a “sensitizer” material, in which a chromophoric species near the REE is first excited, followed by energy transfer to the REE and REE-centered emission, typically through a Dexter or Förster energy-transfer process …”

“…4,5,8,9 Consequently, there is a growing interest in producing REEs from alternative sources, such as electronic waste, 10 coal utilization byproduct streams, 11−13 and industrial wastewaters. 14 Rapid, inexpensive, and sensitive REE characterization techniques are needed both for resource exploration [e.g., locating REE-rich liquid streams such as acid mine drainage (AMD)] 15,16 and for characterizing downstream REE production steps, including the separation, purification, and concentration steps during REE processing. For example, scaled-up facilities have been developed, in which a series of solvent, acid/base, or bio-based 17,18 extraction and precipitation steps are used to isolate REEs from coal, 13,19 coal ash, 13,19,20 and AMD, 21,22 and high-performance analytical methods can be deployed to evaluate the efficiency of and make real-time adjustments to each production step.…”

“…In particular, portable luminescence-based sensors are attractive because they offer up to 1000× higher sensitivity than competing portable techniques (e.g., X-ray fluorescence 23 and laser-induced breakdown spectrometers 24 ) for REEs while providing significantly lower equipment and operating costs relative to inductively coupled plasma mass spectrometry, a nonportable technique. 15,16,25 Several of the REEs in particular are well suited for luminescence-based sensing techniques because they exhibit distinct, element-specific emission bands in the visible and near-infrared regions; these bands arise from f-orbital transitions that are shielded by the outer s-and p-orbitals, yielding narrow, line-like emission bands. 26−28 However, these transitions are parity forbidden, leading to poor absorption and inefficient direct excitation.…”

Sensor System for Rapid Detection of Sensitized Actinide Luminescence

“…Motivation Cont. • Sensitizers have been used to amplify the low luminescent signal via Förster energy transfer -lanthanides (in liquid and solid state) by Ahern et al [1][2][3][4] -actinides (in solid-state) by former graduate group member Zerihun Assefa at ORNL. [5][6][7][8][9] Figure: Diagram of donor/antenna-acceptor/lanthanide system.…”