Structure, dynamics and stability of water/scCO2/mineral interfaces from ab initio molecular dynamics simulations

Mal Soon Lee; B. Peter McGrail; Roger Rousseau; Vassiliki Alexandra Glezakou

doi:10.1038/srep14857

Structure, dynamics and stability of water/scCO₂/mineral interfaces from ab initio molecular dynamics simulations

Mal Soon Lee, B. Peter McGrail, Roger Rousseau, Vassiliki Alexandra Glezakou

Research output: Contribution to journal › Article › peer-review

34 Scopus citations

Abstract

The boundary layer at solid-liquid interfaces is a unique reaction environment that poses significant scientific challenges to characterize and understand by experimentation alone. Using ab initio molecular dynamics (AIMD) methods, we report on the structure and dynamics of boundary layer formation, cation mobilization and carbonation under geologic carbon sequestration scenarios (T = 323 K and P = 90 bar) on a prototypical anorthite (001) surface. At low coverage, water film formation is enthalpically favored, but entropically hindered. Simulated adsorption isotherms show that a water monolayer will form even at the low water concentrations of water-saturated scCO₂. Carbonation reactions readily occur at electron-rich terminal Oxygen sites adjacent to cation vacancies that readily form in the presence of a water monolayer. These results point to a carbonation mechanism that does not require prior carbonic acid formation in the bulk liquid. This work also highlights the modern capabilities of theoretical methods to address structure and reactivity at interfaces of high chemical complexity.

Original language	English
Article number	14857
Journal	Scientific Reports
Volume	5
DOIs	https://doi.org/10.1038/srep14857
State	Published - Oct 12 2015
Externally published	Yes

Funding

This work was supported by the US Department of Energy, Office of Fossil Energy (M.-S. L., B. P. M. and V.-A. G.) and the Office of Basic Energy Science, Division of Chemical Sciences, Geosciences and Biosciences (R.R.), and performed at the Pacific Northwest National Laboratory (PNNL). PNNL is a multiprogram national laboratory operated for DOE by Battelle. Computational resources were provided by PNNL’s Platform for Institutional Computing (PIC), the W. R. Wiley Environmental Molecular Science Laboratory (EMSL), a national scientific user facility sponsored by the Department of Energy’s Office of Biological and Environmental Research located at PNNL and the National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory. The authors are grateful to Dr. S. Kerisit, Dr. D. C. Cantù and Dr. Z. Dohnalek for a critical reading of the manuscript, and F. Verdier (NERSC) for technical assistance.

Funders	Funder number
EMSL
W. R. Wiley Environmental Molecular Science Laboratory
U.S. Department of Energy
Office of Fossil Energy
Biological and Environmental Research
Pacific Northwest National Laboratory

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Access to Document

10.1038/srep14857

Cite this

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