Potential interferences on the pertechnetate-sulfide immobilization reaction

Highly Efficient Uptake of TcO4 - by Imidazolium-Functionalized Wood Sawdust

99Tc is a radioactive fission product, mainly in the form of TcO4 -, with good solubility and mobility in the environment. The development of effective and inexpensive materials to remove TcO4 - from nuclear industry wastewater or contaminated water is significant. Wood sawdust is a byproduct of the wood processing industry and is an abundant, low-cost, and sustainable material. The mesostructure of wood consists of numerous hollow cells that are joined endwise to form an interconnected channel matrix capable of rapid transfer of ions. Imidazolium-functionalized wood sawdust (IM-WS) was synthesized using natural wood sawdust by a two-step reaction. It has excellent properties of TcO4 -/ReO4 - adsorption including rapid adsorption dynamics (30 s to equilibrium), good adsorption stability (pH 3-9), high selectivity (adsorption of 45.4 Re % in 1000 times excess of NO3 - ions, 76.6 Re % in 6000 times excess of SO4 2- ions, and 92.2 Tc % in a simulated mixed solution; after adsorption, the concentration of TcO4 - decreased to 0.056 ppb from the initial concentration of 12.09 ppb in 1000 times excess of SO4 2-), and in particular low production costs. These characteristics give it great prospects for low-level radioactive wastewater treatment and environmental remediation.

Semiconducting layered technetium dichalcogenides: insights from first-principles

The structures and properties of layered technetium dichalcogenides TcX2 (X = S, Se, Te) have been investigated using density functional theory. The equilibrium structures of TcSe2 and TcTe2, adopting distorted Cd(OH)2-type unit cells similar to TcS2, are reported for the first time at the atomic level, along with their electronic properties. In contrast to previous X-ray diffraction analyses, calculations reveal that stoichiometric TcTe2 is not isomorphous to the high-temperature monoclinic phase β-MoTe2. All three compounds are found to be semiconductors with calculated band gaps of 0.9 eV for TcS2, 0.8 eV for TcSe2, and 0.3 eV for TcTe2. The thermal properties of these TcX2 compounds have also been predicted using phonon frequencies calculated with density functional perturbation theory.