Sayandev Chatterjee

Despite decades of research, the reduction behavior of pertechnetate, TcO , is not well understood and represents one of the largest knowledge gaps in the transition metal series. Conventional wisdom presumes the reduction of TcO in aqueous systems to predominantly follow either a rapid two electron, or three electron process to form either a Tc or Tc species.

Selective sequestration of sulfate (SO42-) in the form of barite (BaSO4) from alkaline solutions of high ionic strength containing carbonate is problematic due to the preferential formation of BaCO3. Incorporation of sulfate into the insoluble and thermally stable BaSO4 phase can potentially benefit radioactive waste processing in reducing operational challenges and suppressing volatilization of other waste components such as technetium-99.

The first transuranium element neptunium (Np) exhibits complicated behavior in acidic solutions as it adopts a wide range of oxidation states typically from +3 to +6 and coordinates a large variety of ligands. In particular, accurate determination of Np redox potentials in nitric acid solutions is challenging due to overlapping chemical and electrochemical reactions leading to significant experimental uncertainties.