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Title: Glass-water interactions: Effect of high-valence cations on glass structure and chemical durability

Spectroscopic measurements, dissolution experiments, and Monte Carlo simulations were performed to investigate the effect of high valence cations (HVC) on the mechanisms of glass dissolution under dilute and near-saturated conditions. Raman and NMR spectroscopy were used to determine the structural changes that occur in glass, specifically network formers (e.g., Al, Si, and B), with the addition of the HVC element hafnium in the Na2O Al2O3 B2O3 HfO2 SiO2 system (e.g., Na/(Al+B) = 1.0 and HfO2/SiO2 from 0.0 to 0.42). Spectroscopic measurements revealed that increasing hafnium content decreases N4 and increases the amount of Si–O–Hf moieties in the glass. Results from flow through experiments conducted under dilute and near saturated conditions show a decrease of approximately 100 or more in the dissolution rate over the series from 0 to 20 mol% HfO2. Comparing the average steady-state rates obtained under dilute conditions to the rates obtained for near-saturated conditions reveal a divergence in the magnitude between the average steady state rates measured in these different conditions. The reason for this divergence was investigated more thoroughly using Monte Carlo simulations. Simulations indicate that the divergence in glass dissolution behavior under dilute and near-saturated conditions result from the formation of a low coordination Simore » sites when Si from the saturated solution adsorbs to Hf on the glass surface. The residence time of the newly formed low coordination Si sites is longer at the glass surface and increases the density of anchor sites from which altered layers with higher Si densities can form than in the absence of Hf. These results illustrate the importance of understanding solid water/solid-fluid interactions by linking macroscopic reaction kinetics to nanometer scale interfacial processes.« less
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [2] ; ;  [2] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  3. Univ. Paris-Saclay, Saclay (France)
  4. CEA DEN Lab., d'Etude du Comportement a Long Terme (France)
  5. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Geochimica et Cosmochimica Acta
Additional Journal Information:
Journal Volume: 181; Journal Issue: C; Journal ID: ISSN 0016-7037
The Geochemical Society; The Meteoritical Society
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Environmental Management (EM)
Country of Publication:
United States