Long-term predictions of dissolution behavior of glass waste forms in aqueous environments can have potentially reduced uncertainties by utilizing first-principles informed models. As a starting point, we have developed a model using  a well characterized crystalline aluminosilicate (orthoclase) that has a known structure, but possess key characteristics of waste form glass, such as compositions with multiple cations, pH dependence and formation of secondary phases in dissolution. A Kinetic Monte Carlo study based on first-principles calculations of barriers for water reactions at neutral, protonated and deprotonated sites provided information on the overall disoolution rate and  rate-limiting steps. The dissolution rate far from equilibrium is compared to experiments. We have also extended this approach to multi-component glasses. Using initial amorphous structures generated from classical molecular dynamics, we calculated reaction energies and barriers from first-principles. Insights into the molecular-level mechanisms of glass dissolution will be used for a coarser scale modeling.

First-principles study of barriers for hydrolysis reactions in silicate minerals and glasses

245th National Meeting (2013)

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