Research

Geochemistry of Interfaces

From surfaces to interlayers to clusters

A geoscience project under Sandia's Energy, Climate, & Infrastructure Security mission area.

Problem

Molecular phenomena at the metal oxide-water interface control many geochemical and environmental processes critical to water quality and treatment, the fate and transport of contaminants, radionuclide isolation and waste forms, carbon capture and sequestration, resource extraction, and materials stability and corrosion.

Solution

Our team of scientists is developing state-of-the-art approaches for understanding molecular mechanisms that control the disposition of radionuclides and chemical contaminants in the natural environment. These fundamental investigations, which provide a sound, theoretical basis for accurately predicting the fate of chemicals in groundwater and soil systems, can be used to refine the performance assessment of various waste-treatment practices. By combining the most advanced experimental and spectroscopic methods with state-of-the-art molecular simulation, the research presents an integrated effort to improve our understanding of the mineral-water interface and to develop a predictive capability for evaluating critical geochemical processes.

Achievements

Our scientists' achievements include the following:

  • Developed molecular-modeling tools to improve predictions of mineral structure, mineral dynamics, and adsorption phenomena
  • Characterized the hydroxyl surfaces of soil minerals by using molecular-dynamics simulations with surface-specific vibrational spectroscopies
  • Developed surface complexation models to accurately predict the adsorption of chemical species on mineral surfaces
  • Synthesized novel iron (multiple valence states) and aluminum clusters and characterized the compositions of these clusters; results suggest that aqueous clusters are potential precursors to natural nanomaterials, such as ferrihydrite