Surface interactions of organic ligand-iron oxide/water interfaces on carbon and iron cycling studied using SFG spectroscopy.
EMSL Project ID
50355
Abstract
The proposed work will examine the interfacial phenomena of the organic ligand desferrioxamine B (DFOB) at the iron oxide mineral/water interface using the nonlinear optical spectroscopy technique sum frequency generation (SFG). Experiments will focus on monitoring the change in the DFOB SFG signal as the DFOB is exposed to iron oxide/water interfaces at varying pH and DFOB concentrations. These studies will provide direct evidence of surface coverage, structure and kinetics of complexation and dissolution. Polarization measurements will be conducted to examine adsorbate surface orientation. Results from these experiments on aqueous organic ligand-iron oxide interfaces will provide crucial information about biogeochemical iron and carbon cycling, leading to improved global models. The SFG experiments will be conducted in the Environmental Spectroscopy Laboratory at EMSL, using thin-film hematite samples fabricated by EMSL. This work is dependent on access to the Deposition and Microfabrication and Nonlinear Spectroscopy capabilities at EMSL. Hematite thin films (~20 nm thick) will be deposited onto calcium fluoride substrates using Pulsed Laser Deposition (PLD) for use in the SFG experiments. PLD is not available at the University of Puget Sound. The thin film is required to avoid absorption of the laser light and burning of the sample while maintaining optical reflectivity. The SFG experiments must be conducted at EMSL, as the Environmental Spectroscopy Laboratory houses the most convenient SFG spectrometers to the University of Puget Sound, and the only high-resolution SFG spectrometer currently available for use in the United States.
Project Details
Project type
Limited Scope
Start Date
2018-05-29
End Date
2018-07-29
Status
Closed
Released Data Link
Team
Principal Investigator