Reduction of Pertechnetate by Chemical and Photochemical Approaches and Incorporation of Tc(IV) into Titanium Dioxide

• Published in: European journal of inorganic chemistry Vol. 26; no. 1
• Main Authors: Jovanovic, Ivana Radivojevic, Gallagher, Colleen M. B., Salcedo, Ramsey, Elshendidi, Hossam, Samson, Jacopo, Drain, Charles M., McGregor, Donna, Lukens Jr., Wayne W., Burton‐Pye, Benjamin P., Francesconi, Lynn C.
• Format: Journal Article
• Language: English
• Published: United States ChemPubSoc Europe 08.12.2022
• Subjects: Chemistry; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; photocatalysis; reduction; technetium-99; titanium dioxide; wasteform
• ISSN: 1434-1948

Abstract Technetium‐99 is a prevalent fission product from nuclear waste. The long half‐life (211,000 yr) and environmental mobility of pertechnetate (TcO 4 − ) render Tc particularly challenging to isolate and stabilize. Here we present two approaches for development of potential wasteforms using titanium dioxide, TiO 2 . Approach 1 is a low temperature chemical synthesis of TiO 2 doped with Tc(IV) from TcO 4 − intended to mimic the Tc waste stream from the UREX family of separations and removes 98.5 % of the Tc, mainly present as edge‐shared Tc(IV) pairs. Approach 2 utilizes TiO 2 to photocatalytically reduce TcO 4 − to Tc(IV) stabilized on the surface of or within the TiO 2 lattice. The %Tc removed from solution and adsorbed to TiO 2 is pH dependent, with the maximum Tc(IV) adsorbed at pH 3–4 as either TcO 2 or edge‐sharing Tc(IV) octahedra. The Tc(IV)‐TiO 2 composites materials formed by both approaches are suitable for consolidation into a dense wasteform by Hot Isostatic Pressing (HIPing).