Division of Information Technology, Engineering and the Environment
School of Advanced Manufacturing and Mechanical Engineering
School of Advanced Manufacturing and Mechanical Engineering
Thesis Abstract
The development of solid-liquid extraction systems composed of a mesoporous inorganic framework functionalised with organic molecules show great promise in the area of advanced nuclear fuel cycle (ANFC) back end separations, nuclear medicine and water detoxification. Functionalised mesoporous materials possess the potential to offer remarkable advantages with their chemical versatility, simplicity, higher adsorption capacity and ability to engineer unusual selectivity [1].
In our present study we aim to describe the chemical durability and behaviour of mesoporous mixed metal oxides functionalized with a series of six simple phosphonic acid anchors as model coupling molecules to best obtain an understanding of their chemical stability when immersed in different concentrations over an acidic pH range. The materials have been characterised by DRIFT FT-IR, TGA-DTA, ToF-SIMS and NMR with leaching behaviour and kinetics investigated by ICP-MS elemental analysis.
In all cases, leaching increases as the pH decreases. This is a well known result due to the diminished adsorption of cation ion exchange surfaces by hydrolysis and the dissolution of metal ions within the solid compound. Ligand degradation is independent of parent material composition (i.e. ratio variation) and stability increased with increasing amount of available coordination groups. Grafted molecules with two or more phosphonic acid groups have show to be more stable under the given conditions.
[1] Paiva, A.P. and P. Malik, Recent advances on the chemistry of solvent extraction applied to the reprocessing of spent nuclear fuels and radioactive wastes. Journal of Radioanalytical and Nuclear Chemistry, 2004. 261(2): p. 485-496.
