Aluminum, a non-radioactive element and typically existed in the form of boehmite (AlOOH), gibbsite (Al(OH)3), and sodium aluminate (NaAlO2), makes up about two thirds of the sludge in the high-level waste tanks at Department of Energy Hanford site in eastern Washington state. Caustic dissolution treatments are performed to reduce the amount of Al so that it is no longer the waste-limiting component in the final vitrified HLW glass waste form. Dissolution tests have shown that the surface area-normalized dissolution rate of boehmite in the tank waste sludge is over an order of magnitude lower than that predicted from pure boehmite under the same treatment conditions. It has been hypothesized that Cr(III), which is also recalcitrant to the dissolution process, and other trace metals in the sludge, might react with the aluminum phases and inhibit their dissolution. In this work, we synthesized Eu(III)-bearing nano-platelets of gibbsite and boehmite in which Eu(III) is either adsorbed on the aluminum phases after the synthesis or incorporated into the phases during the synthesis. An array of spectroscopy and microscopy techniques including X-ray diffraction, Raman spectroscopy, laser-induced time-resolved fluorescence spectroscopy, surface-specific sum-frequency generation–vibrational spectroscopy and scanning electron microscopy, are applied to characterize the structure and bonding of the Eu(III) ion in the aluminum phases. Dissolution rate of Eu(III)-bearing phases were measured and compared with pure phases as well as the corresponding Cr(III)-bearing phases.

Synthesis and spectroscopy study of Eu(III)-bearing nano-platelet gibbsite and boehmite

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.