Rare Earth Elements (REEs: La–Lu, Y, and Sc) are critical components for technological innovations, therefore more effective methods for the domestic extraction and purification of REEs are in ever-increasing demand. Metal-chelating polymers have great potential in these applications due to their relatively low cost and high affinity for target elements. However, while much research has focused on specific ligands attached to polymers, little is known about the effect of polymer architecture itself on metal chelation.
This dissertation reports recent progress in the design, synthesis, and application of polymers for the chelation of various REEs. In addition to synthesizing a series of metal-chelating polymers, we elucidated the thermodynamics of binding using isothermal titration calorimetry (ITC) to gain insight into the specific relationship between polymer structure and metal binding. ITC enables the direct measurement of the binding affinity (Ka), enthalpy changes (ΔH), and stoichiometry of the interactions between macromolecules and metal ions in solution. The thermodynamics of metal chelation underpins many technologies for REE extraction. Consequently, elucidating these parameters enables the rational design of future materials. / Doctor of Philosophy / Rare-Earth Elements (REEs) are critical metals used in many modern technologies, therefore more effective methods for the recovery and purification of REEs are in ever-increasing demand. Metal-chelating polymers—materials that can bind metals—have great potential in these applications due to their relatively low cost and high affinity for target elements. However, while much research has focused on the specific metal-binding group attached to the polymer, little is known about the effect of polymer architecture itself on metal chelation.
This dissertation reports recent progress in the design, synthesis, and application of materials that bind to various REEs. In addition to synthesizing a series of metal-binding polymers, we measured the heat absorbed or produced during metal-binding interactions. These experiments produced fundamental insights into the interactions between the polymers, metals ions, and water molecules in solution. Overall, this work produces a depiction of the polymer–metal binding process, which enables insight into each polymer's properties as a metal-binding material. Future researchers can use these guidelines to develop the next generation of materials for the extraction of these critical metals.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/110401 |
| Date | 01 June 2022 |
| Creators | Archer, William Ryan |
| Contributors | Chemistry, Schulz, Michael, Esker, Alan R., Deck, Paul A., Tanko, James M. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf, application/x-zip-compressed |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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