Type
Text
Type
Dissertation
Advisor
Grey, Clare P. | Koch, Stephen | Hsiao, Benjamin | Reeder, Richard J. | Elzinga, Evert.
Date
2015-08-01
Keywords
Chemistry | polymerization, sorption mechanisms, tungstate, X-ray absorption spectroscopy
Department
Department of Chemistry.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/77112
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
The importance of this study is related to releases of tungsten to environment as a result of its widespread used in industrial, civil, and military applications. Recent studies have reported the oxidative dissolution of tungsten metal or alloy under appropriate pH and redox conditions resulting in the formation of tungstate, W(VI), which occurs mainly as oxyanions--some of which have a high solubility in aquatic and soil systems. Therefore, the environmental fate of W ultimately depends on an understanding of tungstate geochemistry. We will discuss the role of tungstate speciation on its sorption mechanism on environmentally relevant mineral surfaces, including aluminum oxyhydroxide, hydroxyapatite (HAP), and layered double hydroxide (LDH). Tungstate speciation in aqueous systems is strongly related to its mobility, toxicity, and bioavailability. Tungstate speciation in aqueous solution was investigated using reported stability constants of known tungstates, combined with characterization by X-ray absorption spectroscopy (XAS) and electrospray ionization mass spectroscopy (ESI-MS). Batch uptake experiments were carried out to investigate tungstate sorption behavior on boehmite over a range of environmentally relevant conditions such as pH, tungstate concentration, and ionic strength. Tungsten L13-edge XANES was used to distinguish coordination environment around W atoms. The local structure and coordination of tungsten at the surface were determined using tungsten L3-edge EXAFS, which allowed us to further characterize the binding mechanisms. Various sorption mechanisms such as the surface polymerization (aluminum oxide), the intercalation reaction (LDH), and coprecipitation (HAP) were suggested depending on the properties of mineral surfaces in this study. This work will provide a foundation for subsequent studies of tungstate sorption on other solids. The findings also have possible implications for tungsten toxicity in natural environments. | 210 pages
Recommended Citation
Hur, Hyuck, "Tungstate Sorption Mechanisms on Various Mineral Surfaces: Systematic Batch Uptake Experiments and Spectroscopic Studies" (2015). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2949.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2949