In analysis of complex nuclear forensic matrices containing lanthanides, actinides and matrix elements, rapid selective extraction of Am/Cm for quantification is challenging due to the difficult separation of Am/Cm from lanthanides. This project attempts to develop novel separation processes for Am/Cm separation utilising liquid-liquid extraction and extraction chromatography based on soft N-donor triazine extractants. Selective extractants were identified and synthesized and a liquid-liquid separation procedure was developed. Of these ligands, CyMe4-BTPhen, CyMe4-BTBP, CA-BTP and CA-BTPhen were compared for application to complex matrices. The developed process allows for purification and quantification of Am and Cm (recoveries 80–100%) and other major actinides in < 2 days without the use of multiple columns or thiocyanate, yielding a full data set. The process developed was shown to be unaffected by Ca/Fe/Al (10 mg mL-1) and thus requires little pre-treatment of samples. Due to limited availability of media for separation of americium using EC, we synthesized and tested a novel covalently-linked EC resin, utilising a triazine soft N-donor (Me4BTPhen) extractant for americium extraction. The resin was generated by conjugation of a Me4BTPhen derivative with poly(vinylbenzyl) chloride to generate PVB-Me4BTPhen. PVB-Me4BTPhen was shown to extract americium from a complex matrix simulating nuclear forensic samples, and containing lanthanides, actinides and matrix elements with high Am (III) recovery ( > 90%) and low extraction of other elements, and provides an alternative separation process for Am (III) extraction. Adsorption was also investigated as an alternative, more flexible approach to resin preparation. BTBP/BTPhen Am selective triazine ligands were adsorbed onto Amberlite XAD-7, then characterised and tested for Am/Eu selectivity, complexation kinetics and polymer loading. These polymers were tested with complex matrices in conjunction with AG1-X8 anion exchange chromatography to achieve a complete isotope separation and quantification method. From these results, the resin capacity factor (KD) as a function of HNO3 concentration was calculated, allowing potential separation methods to be designed. Selective americium extractants from the BTPhen ligand family have been identified through this work, and we also report a study of functionalisation of BTPhen ligands to help design new selective Am extractants by determining the effects on solubilities and americium extraction capabilities of variations in substituents. The data obtained show trends that could assist in future ligand design.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:677765 |
| Date | January 2015 |
| Creators | Higginson, Matthew |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://www.research.manchester.ac.uk/portal/en/theses/rapid-radiochemical-separations-of-americium-from-actinides-mixed-fission-products-and-matrix-elements(58eb5847-48d7-49dc-80d4-a53a2e4bab56).html |
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