Reductive Transformation of Iron Oxides: Coupled Solution and Solid-State Pathways
EMSL Project ID
25629
Abstract
Reductive transformation of Fe(III)-oxides such as  Fe2O3 (hematite) by aqueous dissolution / re precipitation is a central part of the natural biogeochemical iron cycle in the environment. This transformation involves conversion of surface Fe(III) to Fe(II) by electron transfer from adsorbed reductant molecules followed by Fe(II) solubilization and precipitation of new phases. The process can enter an autocatalytic stage when released Fe(II) re-encounters and reduces the hematite surface. Some Fe(III)-oxides such as hematite have a propensity for fast charge redistribution and limited electron diffusion by solid-state electron transport. We propose a closely-coupled experimental and theoretical / computer modeling study that focuses on characterizing the pathways involved in the reductive transformation of hematite. The central objective is to determine mechanisms of transformation by linking surface-specific microscopic observations in conjunction with using a combination of small and large-scale molecular simulations. Computational molecular modeling in the form of molecular dynamics (MD) simulations, ab initio calculations, and kinetic Monte Carlo simulations (KMC) will be performed to develop one-of-a-kind atomistic models that will allow us to assess the effects of solid-state charge migration on the rate of growth and the morphology of dissolution and growth features for comparison with the experimental observations. We request access to the ambient scanning probe microscopy laboratory in the EMSL building in room 1544 under the purview of the Environmental Spectroscopy and Biogeochemistry Facility. We request occasional access to the XRD laboratory, the electron microscopy laboratory, and the XPS laboratory. For computational resources, we request 150,000 node hours on mpp2 and access to the SGI system 'nwvisus' and the Linux cluster 'Spokane'.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2007-05-31
End Date
2010-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Boily JF, SME Chatman, and KM Rosso. 2011. "Inner-Helmholtz Potential Development at the Hematite (alpha-Fe2O3) (001) Surface." Geochimica et Cosmochimica Acta 75(15):4113-4124.
Gibbs GV, AF Wallace, DF Cox, PM Dove, RT Downs, NL Ross, and KM Rosso. 2009. "Role of Directed van der Waals Bonded Interactions in the Determination of the Structures of Molecular Arsenate Solids." Journal of Physical Chemistry A 113(4):736-749.
Gibbs GV, AF Wallace, DF Cox, RT Downs, NL Ross, and KM Rosso. 2009. "Bonded Interactions in Silica Polymorphs, Silicates and Siloxane Molecules ." American Mineralogist 94(8-9):1085-1102.
Gibbs GV, AF Wallace, RT Downs, NL Ross, DF Cox, and KM Rosso. 2010. "Thioarsenides: A case for long-range directed Lewis acid-base van der Waals interactions." PNNL-SA-70964, Pacific Northwest National Laboratory, Richland, WA.
Gibbs GV, AF Wallace, R Zallen, RT Downs, NL Ross, DF Cox, and KM Rosso. 2010. "Bonded Paths and van der Waals Interactions in Orpiment, As2S3." Journal of Physical Chemistry A 114(23):6550-6557.
Gibbs GV, RT Downs, DF Cox, KM Rosso, NL Ross, A Kirfel, T Lippmann, W Morgenroth, and TD Crawford. 2008. Experimental Bond Critical Point and Local Energy Density Properties Determined for Mn-O, Fe-O, and Co-O Bonded Interactios for Tephroite, Mn2SiO4, Fayalite, Fe2SiO4, and Co2SiO4 Olivine and Selected Organic Metal Complexes: Comparison with Properties Calculated for Non-Transition and Transition Metal M-O Bonded Interactions for Silicates and Oxides. J. Phys. Chem. A 112(37):8811-8823.
Gibbs GV, RT Downs, DF Cox, NL Ross, CT Prewitt, KM Rosso, T Lippmann, and A Kirfel. 2008. "Bonded Interactions and the Crystal Chemistry of Minerals: A Review." Zeitschrift fur Kristallographie 223(1-2):1-40. doi:10.1524/zkri.2008.0002
Gibbs GV, RT Downs, DF Cox, NL Ross, MB Boisen, Jr., and KM Rosso. 2008. "Shared and closed-shell O-O interactions in silicates." Journal of Physical Chemistry A 112(16):3693-3699
Meakin P, and KM Rosso. 2008. "Simple Kinetic Monte Carlo Models for Dissolution Pitting Induced by Crystal Defects." Journal of Chemical Physics 129(20):204106. doi:10.1063/1.3021478
Rosso KM, S Yanina, CA Gorski, P Larese-Casanova, and M Scherer. 2010. "Connecting Observations of Hematite (a Fe2O3) Growth Catalyzed by Fe(II)." Environmental Science & Technology 44(1):61-67.
Yanina SV and KM Rosso. 2008 "Linked Reactivity at Mineral-Water Interfaces Through Bulk Crystal Conduction." Science, 320(5873):218-222.
Zarzycki PP, and KM Rosso. 2009. "Origin of two time-scale regimes in potentiometric titration of metal oxides. A replica kinetic Monte Carlo study." Langmuir 25(12):6841-6848.
Zarzycki PP, and KM Rosso. 2010. "Molecular Dynamics Simulation of the AgCl/Electrolyte Interfacial Capacity." Journal of Physical Chemistry C 114(21):10019-10026. doi:10.1021/jp100074h
Zarzycki PP, SN Kerisit, and KM Rosso. 2010. "Molecular Dynamics Study of the Electrical Double Layer at Silver Chloride Electrolyte Interfaces ." Journal of Physical Chemistry C 114(19):8905-8916.
Zarzycki PP, SN Kerisit, and KM Rosso. 2011. "Computational methods for intramolecular electron transfer in a ferrous-ferric iron complex." Journal of Colloid and Interface Science 361(1):293-306.