Speciation and fractionation of less-studied technology-critical elements (Nb, Ta, Ga, In, Ge, Tl, Te): A review

Abstract

Technology-critical elements (TCE) are of great relevance in the development of key emerging technologies, including renewable energy, energy efficiency, electronics and the aerospace industry. A sudden increase in industrial demand in support of an emerging technology or unexpected cutoff from a supply of critical minerals can have a drastic impact on national security and economic health. The growing release of TCEs requires understanding their mobility, reactivity, and chemical transformations in the environment, which are critically dependent on their chemical form. Here we review the speciation of less studied technology-critical elements (LSTCEs): Nb, Ta, Ga, In, Ge, Tl and Te. We discuss the trends in analytical techniques using in TCEs speciation. The development of analytical techniques significantly increases the interest of researchers in these elements and species. In particular, there is still little information in the literature on the speciation of niobium and tantalum.