Elemental and particularly isotopic analysis of uranium, e.g. for nuclear forensics and environmental monitoring, is often hindered by the extremely low concentration levels and/or sample matrix effects, requiring highly selective pre-concentration procedures to enrich the analyte and to eliminate other co-existing metals.
Conventional liquid-liquid extraction is solvent and time consuming, and often not compatible with the following detection e.g. by ICP-ES/MS due to the use of highly volatile, water-immiscible and viscous organic solvents. Various strategies ranging from flow injection, dilution with methanol, evaporation-reconstitution, to back extraction have been employed to minimise the effects of organic solvents. Also liquid-liquid micro-extraction and solid phase extraction procedures have recently attracted increasing research interest to improve the efficiency and reduce the consumption of solvents and reagents
Numerous new triazine agents have been reported aiming to separate actinides from chemically very similar lanthanides in spent nuclear fuels. For instance, hydrophobic bis-1,2,4- triazine ligands are widely used to form actinide complexes selectively in the organic phase, while alternatively hydrophilic sulfonated bis-1,2,4- triazine ligands can be used in the aqueous phase for back extraction. Uranium is known to form complexes with the bis-triazine ligands as U(VI) (J.C. Berthet, P. Thuery, M.R.S. Foreman, M. Ephritikhine, Radiochim. Acta, 2008, 96, 189-197). The separation factors are commonly tested for artificial and real nuclear wastes using Kerosene/octanol solvent system and a γ-ray spectrometer with no attempt for wider analytical applications.
In this project, various new triazine ligands will be studied for selective extraction of uranium from other more environmentally common elements including lanthanides and iron using multi-element ICP-ES detection. Effects of acidity, reagent concentration, contact time, masking agents and organic solvents will be investigated; different extraction approaches will be explored to optimise the extraction efficiency. The established procedures will be applied to environmental matrices for uranium analysis.
Please note eligibility requirement:
• Academic excellence of the proposed student i.e. 2:1 (or equivalent GPA from non-UK universities [preference for 1st class honours]); or a Masters (preference for Merit or above); or APEL evidence of substantial practitioner achievement.
• Appropriate IELTS score, if required.
• Applicants cannot apply for this funding if currently engaged in Doctoral study at Northumbria or elsewhere.
For further details of how to apply, entry requirements and the application form, see https://www.northumbria.ac.uk/research/postgraduate-research-degrees/how-to-apply/
Please note: Applications should include a covering letter that includes a short summary (500 words max.) of a relevant piece of research that you have previously completed and the reasons you consider yourself suited to the project. Applications that do not include the advert reference (e.g. SF20/…) will not be considered.
Deadline for applications: 1st July for October start, or 1st December for March start
Start Date: October or March
Northumbria University takes pride in, and values, the quality and diversity of our staff. We welcome applications from all members of the community. The University holds an Athena SWAN Bronze award in recognition of our commitment to improving employment practices for the advancement of gender equality.
Please direct enquiries to Dr Renli Ma ([email protected]
1. J.L. Mas, R. Ma, C. McLeod, J. González-Labajo, A. Cox and P. Watson, Determination of 238U/234U isotope ratios in environmental waters by quadrupole ICP-MS after U stripping from alpha-spectrometry counting sources, Anal. Bioanal. Chem., 2006, 386, 152-160.
2. D. Bellis, R. Ma, N. Bramall, C.W. McLeod, N. Chapman and K. Satake, Airborne uranium contamination – as revealed through elemental and isotopic analysis of tree bark, Environ. Pollu., 2001, 114, 383-387.
3. D.J. Bellis, R. Ma and C.W. McLeod, Characterisation of airborne uranium and thorium contamination in Northern England through measurement of U, Th and 235U/238U in tree bark, J. Environ. Monit., 2001, 3, 198-201.
4. D. Bellis, R. Ma, N. Bramall and C.W. McLeod, Airborne emission of enriched uranium at Tokai-mura, Japan, Sci. Total Environ., 2001, 264, 283-286.
5. R. Ma, D. Bellis and C.W. McLeod, Isotopic analysis of uranium in tree bark by ICP-MS: a strategy for assessment of airborne contamination, Anal. Chem., 2000, 72, 4878-4881.
6. R. Ma and F. Adams, Flow injection sorbent extraction with dialkyldithiophosphates as chelating agent for the determination of cadmium, copper and lead by flame atomic absorption spectrometry, Spectrochim. Acta, 1996, 51B, 1917-1923.
7. A. V. Zaytsev, R. Bulmer, V. N. Kozhevnikov, M. Sims, G. Modolo, A. Wilden, P. G. Waddell, A. Geist, P. J. Panak, P. Wessling, F. W. Lewis, Exploring the Subtle Effect of Aliphatic Ring Size on Minor Actinide Extraction Properties and Metal Ion Speciation in Bis‐1,2,4‐Triazine Ligands, Chem. Eur. J., 2019 (DOI: 10.1002/chem.201903685).
8. S. D. Reilly, J. Su, J. M. Keith, P. Yang, E. R. Batista, A. J. Gaunt, L. M. Harwood, M. J. Hudson, F. W. Lewis, B. L. Scott, C. A. Sharrad, D. M. Whittaker, Plutonium Coordination and Redox Chemistry with the CyMe4-BTPhen Polydentate N-Donor Extractant Ligand, Chem. Commun., 2018, 54, 12582-12585.
9. F. W. Lewis, L. M. Harwood, M. J. Hudson, A. Afsar, D. M. Laventine, K. Šťastná, J. John, P. Distler, Separation of the Minor Actinides Americium(III) and Curium(III) by Hydrophobic and Hydrophilic BTPhen Ligands: Exploiting Differences in their Rates of Extraction and Effective Separations at Equilibrium, Solvent Extr. Ion Exch., 2018, 36, 115-135.
10. F.W. Lewis, L.M. Harwood, M.J. Hudson, A. Geist, V.N. Kozhevnikov, P. Distler, J. John, Hydrophilic sulfonated bis-1,2,4-triazine ligands are highly effective reagents for separating actinides(III) from lanthanides(III) via selective formation of aqueous actinide complexes, Chem. Sci., 2015, 8, 4812-4821.