The reaction kinetics of glass is controlled by matrix dissolution and ion exchange (IEX). Dissolution of an alkali-rich simulated borosilicate waste glass was investigated using single-pass flow-through (SPFT) experiments. Experiments were conducted as a function of temperature, pH, and solution composition by varying the SiO2 (aq) activity in the influent solution. Results showed that under dilute conditions matrix dissolution increased with increasing pH and temperature, and decreased with increasing SiO2 (aq) activity. IEX rates decreased with increasing pH and temperature, and increased with increasing SiO2 (aq) activity. Over the solution composition range interrogated in this study the dominant dissolution mechanism changed from matrix dissolution to IEX. These results suggest that “secondary” reactions may become dominant under certain environmental conditions and emphasize the need to incorporate these reactions into dissolution rate models.
Revised: March 5, 2008 |
Published: August 1, 2004
Citation
Pierce E.M., B.P. McGrail, J.P. Icenhower, E.A. Cordova, J.L. Steele, and S.R. Baum. 2004.Kinetic Rate Law Parameter Measurements on a Borosilicate Waste Glass: Effect of Temperature, pH, and Solution Composition on Alkali Ion Exchange. In American Chemical Society Division of Environmental Chemistry. Preprints of extended abstracts presented at the 228th ACS National Meeting, Philadelphia, PA August 22-26, 2004, 44, 1151-1158. Washington, District Of Columbia:American Chemical Society.PNNL-SA-41693.