THE NATURE OF ACTINIDE SORPTION ON MONOSODIUM TITANATE (MST): PDF INVESTIGATIONS OF A FUNCTIONAL NANO-MINERAL FOR REMEDIATING HIGH-LEVEL NUCLEAR WASTE

Ion exchange is a key technique for the separation, purification and concentration of cations and anions that may have commercial value or are hazardous. In this class of materials the actinides present particular challenges, such as the recovery of actinides and fission products found in irradiated nuclear fuels. Important parameters that one can tune for successful ion-exchange separations include the chemical and physical properties of the ion exchanger, the chemical composition of feed and eluting solutions, oxidation state, temperature, and pressure. A key metric in ion-exchange separations is the inherent selectivity of an ion-exchanger for a particular sorbate. This is particularly true when the feed solution is comprised of multiple chemically similar ions.

We propose a systematic study of the titanium-based exchangers, such as sodium titanates, which are known to selectively separate strontium actinide ions from high ionic-strength solutions, in order to determine the mechanism of selectivity. Because these are nano-crystalline materials we employed high energy x-ray scattering and the Pair Distribution Function to gain insight into the structures of these materials in their native and ion-exchanged forms.