New sensor can detect valuable rare earth element in nontraditional sources
Low concentrations of terbium could be identified from acid mine drainage and other waste sources
By Gail McCormick
UNIVERSITY PARK, Pa. — A new luminescent sensor can detect terbium, a valuable rare earth element, from complex environmental samples like acid mine waste. The sensor, developed by researchers at Penn State, takes advantage of a protein that very specifically binds to rare earth elements and could be harnessed to help develop a domestic supply of these metals, which are used in technologies such as smart phones, electric car batteries, and energy efficient lighting. A paper describing the sensor appears Aug. 25 in the Journal of the American Chemical Society.
Terbium, one of the rarest of the rare earth elements, produces the green color in cell phone displays and is also used in high-efficiency lighting and solid-state devices. However, there are a variety of chemical, environmental and political challenges to obtaining terbium and other rare earth elements from the environment. Developing new sources of these metals also requires robust detection methods, which poses another challenge. For example, the gold standard method of detecting rare earth elements in a sample — a type of mass spectrometry called ICP-MS — is expensive and not portable. Portable methods, however, are not as sensitive and do not perform well in complex environmental samples, where acidic conditions and other metals can interfere with detection.