Molecular understanding of nutrient sorption on model mineral surfaces
EMSL Project ID
50200
Abstract
Iron (Fe)-containing minerals exert a significant influence on soil and sediment geochemistry, such as the cycling of nitrogen (N) and phosphorus (P) nutrients in the bioavailable form of dissolved oxyanions. Initial efforts have been made to understand the nature of chemisorption of N- and P-oxyanions on Fe oxides, where the mode and extent of adsorption may depend on the nature of the mineral surface. The study of model surfaces grown by molecular beam epitaxy (MBE) and pulsed laser deposition (PLD) can disentangle the roles of crystallography and defects, metal valence, and hydroxylation in nutrient sorption and transformation. We will employ a multimodal in situ approach to investigate the sorption of N- and P-oxyanions by infrared spectroscopy (FTIR, SFG-VS), atomic force microscopy (AFM), and ambient pressure X-ray photoelectron spectroscopy on model oxide surfaces to elucidate the molecular interactions that occur at the mineral/water interface. Together with modeling, these techniques will elucidate the molecular nature and adsorption geometry of species such as nitrate and phosphate on ubiquitous iron (Fe)-containing minerals including hematite and magnetite. Key instrumentation such as the MBE, PLD, AFM, FTIR, SFG-VS, characterization by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and high-performance computing facility being hosted in EMSL is a major advantage of this effort involving synergistic thin film synthesis, multimodal characterization, and theoretical modeling. EMSL is the only location where all of these capabilities and accompanying technical and scientific expertise exist and is thus critical to achieving the goals of the proposed work.By bringing together synergistically coordinated synthesis, multimodal in situ characterization, and modeling efforts, this project will establish the intrinsic sorption capacity of Fe oxide crystallographic facets, as well as the contribution of surface defects, integral parameters for input into multiscale modeling the geochemical processes driving nutrient cycling in soils, terrestrial/aquatic interfaces, and subsurface environments. This mechanistic understanding of nutrient adsorption to mineral surfaces is essential to predict how changing conditions may alter nutrient availability within the soil ecosystem.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2018-10-01
End Date
2021-12-31
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members