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 SO₄²⁻), and in particular low production costs. These characteristics give it great prospects for low-level radioactive wastewater treatment and environmental remediation.