From Surfaces to Interlayers to Clusters

Objective

clay-ion
Molecular-scale understanding of processes at mineral-water interfaces including adsorption at mineral surfaces in soils and sediments to characterize and develop predictive models of atomic and molecular structures, wetting, adsorption, redox, and other processes.

Tasks

  1. Molecular Simulation and Spectroscopy of Dynamical Processes at Mineral-Aqueous Solution Interfaces
  2. Adsorption Equilibrium and Kinetics at Goethite-Water and Related Interfaces
  3. Reactivity of Structural Fe(II)/Fe(III) Couple in Fe-rich Clay Minerals

Molecular Dynamics Simulations Predict Fate of Uranium in Sediments

Scientific Achievement

  • Large-scale molecular simulations identify  structural properties of aqueous uranium adsorbed on mineral surfaces.

Significance and Impact

  • Detailed molecular perspective will improve the fidelity of nuclear waste performance assessment for complex natural systems in which accurate adsorption processes are difficult to assess.
  • This work will inform government and regulatory agencies for approving and instituting nuclear waste repositories, and guide treatment of waste sites.

Research Details

  • Solution structure at the mineral-solution interface identifies adsorption mechanisms of naturally occurring ions (K+) and uranyl ions (UO22+).
  • Surface charge due to adsorbed uranyl ions is consistent with spectroscopic measurements (second harmonic generation).

Shale Poromechanics

Heterogeneity, Flow, Failure, and Creep

Objective

Fundamental Understanding of Shale Multiphysics for Subsurface Engineering Applications

 Tasks

  1. Shale Mechanics Across Scales
    • Micropillar nanoindentation & upscaled mechanics
    • In Situ neutron imaging with deformation
  2. Nano-to-Core Transport Modeling
    • Multiscale imaging across scales
    • Stress-dependent permeability
    • Pore-to-core scale modeling
  3. Creep Response at In Situ Conditions
    • Long term time-dependent mechanics
    • Validated creep law development

Center for Frontiers of Subsurface Energy Security – EFRC

CFSES_logo

Challenge 1:
Sustaining large storage rates
Challenge 2:
Using pore space with
unprecedented efficiency
Challenge 3:
Controlling undesired or
unexpected behavior
Theme 1:
Fluid–Assisted Geomechanics
  • Crack–tip chemo–mechanics
  • Phase–field modeling
  • Cohesive zone modeling
  • Fracture network analog sites
  • Bulk rock weakening evaluation
  • Influence of chemistry in frictional slip
Theme 2:
Multifluid Geochemistry
  • Crack–tip chemomechanics
  • Bravo Dome brine–gas mass transfer
  • Chemistry at the fluid–fluid interface
  • Crack–tip chemomechanics
  • Reactions of C02 with clay minerals
Theme 3:
Buoyancy–Driven Multiphase Flow
  • Meter–scale experiments
  • Core–scale X–ray CT experiments
  • Meter–scale experiments
  • Core–scale X–ray CT experiments
  • Mesoscale modeling and invasion–percolation modeling
  • Ganglion dynamics modeling
  • Nanoparticle experiments