Dissertation
RELATING ANISOTROPIC PARTICLE PROPERTIES AND CLUSTER DYNAMICS TO BOEHMITE AGGREGATION AND GIBBSITE SOLUBILITY IN SODIUM HYDROXIDE
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000005426
Handle:
https://hdl.handle.net/2376/119626
Abstract
The dissolution and precipitation reactions of gibbsite and boehmite in caustic solutions are not well understood, despite over a century of research. It is becoming apparent that more advanced chemical and physical descriptions will be needed to fully understand the reactions. In this work it is shown how ion and solvent cluster diffusion drives the gibbsite solubility equilibrium and how anisotropic particle properties (e.g., physical geometry and colloidal forces) unexpectedly impact boehmite aggregation. The underlying causes of these phenomena are typically ignored in classical chemical descriptions. For gibbsite solubility, it is shown how the strength of the hydrogen bonding network controls cluster diffusion and the solubility at equilibrium. The overall impact can be estimated by measuring diffusion coefficients and could potentially be used to predict solubility for complex systems. For boehmite rheology, it is demonstrated that the delicate balance of colloidal and shear forces is influenced by the shape and size of non-spherical nanoscale aggregates. The resulting orientation-dependent interactions cause an unexpectedly large suspension viscosity and shear thickening during flow. Furthermore, control over these phenomena through a combination flow conditions and chemical environment is demonstrated. In addition, a new model was developed and evaluated for obtaining size and shape parameters of polydisperse fractal aggregates. The research uses a unique combination of solubility measurements, rheology, synchrotron small angle X-ray scattering, and pulsed-field gradient nuclear magnetic spectroscopy to demonstrate how the interplay of nanoscale and smaller forces result in measurable macroscopic properties. The results of this work will benefit our fundamental understanding of aluminum (oxy)hydroxide systems and increase the predictably of models used by engineers developing processes for handling nuclear waste.
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Details
- Title
- RELATING ANISOTROPIC PARTICLE PROPERTIES AND CLUSTER DYNAMICS TO BOEHMITE AGGREGATION AND GIBBSITE SOLUBILITY IN SODIUM HYDROXIDE
- Creators
- Anthony James Krzysko
- Contributors
- Sue B Clark (Advisor)Lawrence M Anovitz (Committee Member)James M Boncella (Committee Member)Cornelius F Ivory (Committee Member)Carolyn I Pearce (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Chemistry
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 187
- Identifiers
- 99900592259401842
- Language
- English
- Resource Type
- Dissertation