PNNL

Abstract

Because of their good physical and chemical durability, relatively high salt loading capacity, and low leachability, sol-gel-derived, organic-inorganic hybrid materials (polycerams) show promise as media that could be used to stabilize high salt wastes. Use of this technique has been hindered by the need for highly volatile and flammable organic solvents in the fabrication process. In an effort to overcome this hinderance, we carried out initial development of an alternative production approach based on an aqueous emulsion technology and a “phase inversion” phenomenon that results in encapsulation of the waste form. Our major interests focused on understanding the phenomena and optimizing fabrication methods to produce a final waste form with excellent waste stabilization characteristics. Scanning electron microscopy was used to obtain the microstructures of the waste forms for understanding the migration, distribution, and encapsulation of the salt in the waste forms. The leaching rate of the salt from a waste form was quantified by means of conductivity measurement.