Covalent Immobilization of Minor Actinide Selective Ligands Korea
Covalent Immobilization of Minor Actinide. Selective Ligands Korea April 2016 Laurence Harwood Ashfaq Afsar, Joe Cowell Petr Distler, Chad Edwards, Andreas Geist, Mark E. Hodson, Michael J. Hudson, Jan John, Dominic M. Laventine, Elizabeth J. Shaw, Clint Sharrad, James Westwood, Roger Whitehead. 30 October 2020 © University of Reading 2008 www. reading. ac. uk
The current bench-mark liquid-liquid separation ligand for minor actinides: Cy. Me 4 BTPhen Fixing the Cy. Me 4 BTBP molecule into the desired ligating conformation by preparing the corresponding phenanthroline derivative – Cy. Me 4 BTPhen – solves the poor extraction kinetics demonstrated by Cy. Me 4 BTBP
Original Synthesis of Cy. Me 4 -BTPhen 56% quantitative 97% 41% over two steps
Screening Results for Cy. Me 4 -BTPhen Ligand in 1 -octanol (0. 01 M) 241 Am(III) + 152 Eu(III) (1 k. Bq/m. L each) in HNO 3 of varied concentrations Contact time = 60 mins at 22 o. C Significantly faster extraction kinetics than Cy. Me 4 -BTBP without added DMDOHEMA F. W. Lewis, L. M. Harwood, M. J. Hudson, M. G. B. Drew, J. F. Desreux, G. Vidick, N. Bouslimani, G. Modolo, A. Wilden, M. Sypula, T. -H. Vu and J. -P. Simonin, J. Am. Chem. Soc. , 2011, 133(33), 13093 -
Solution Speciation: ML 2 Favoured; ML possible Stacked 1 H NMR plots C 5 -BTPhen + Ln(NO 3). 6 H 2 O in CD 3 CN C 5 -BTPhen + Lu(NO 3) in CD 3 CN 100 BTPhen species % 100 80 2: 1 complex 60 1: 1 complex 40 Free ligand 80 60 2: 1 complex 1: 1 complex 40 Free Ligand 20 20 0 0. 2 0. 4 0. 6 0. 8 1 La equivalents added 1. 2 1. 4 0 0. 5 1 Lu equivalents added 1. 5
Solution Phase Speciation: ML 2 Usual [Eu(Cy. Me 4 -BTPhen)2(NO 3)](NO 3)2 (Hydrogens and counter-ions omitted for clarity)
Solution Phase Speciation: ML less favoured YCy. Me 4 -BTPhen(NO 3)3 • Me. CN (Me. CN omitted for clarity)
Ligands Immobilized on Magnetic Nanoparticles Liquid-liquid extraction • Requires substantial tankage and reagents • Generates significant quantities of secondary waste • Not suitable for low concentrations Immobilized ligands • Efficient separation of particles • Simple, versatile and compact • Minimized secondary waste • Suitable for low concentrations (legacy wastes), particularly sludges • Good kinetics
Ligands Immobilized on Magnetic Nanoparticles dispersed in water (colloidal solution). Nanoparticles extracted on application of magnetic field.
Core-shell MNP Synthesis % Transmittance 100 90 80 Iron Oxide MNPs 70 Silica-Coated MNPs 60 Iodoalkyl-Functionalized MNPs 50 40 30 3000 2500 2000 1500 1000 Wavelength, cm-1 Infra red spectrum SEM
Immobilization of neocuproine (Cu 2+ selective): “Proof of concept” + 100 90 Weight (%) % Transmittance 100 80 70 Iodoalkyl-Functionalized MNPs 60 50 80 70 Neocuproine-Functionalized MNPs 60 40 30 3000 90 50 2500 2000 Wavelength, 1500 cm-1 Infra red spectrum 1000 0 200 400 600 Temperature (°C ) 800 Thermo gravimetric analysis 1000
Extraction Results: Cu 2+ 12 ppm of Cu(II) solutions (12 m. L) 12 mg of MNPs Shaking at 2500/min Separated by neodymium magnet Removal Efficiency (%) 100 80 60 40 Removal % 20 Si. O 2 -coated MNPs Iodoalkylfunctionalized Si. O 2 coated MNPs Neocuproine functionalized MNPs 17 30 99 0 2 3 4 5 6 7 8 100 Removal Efficiency (%) Initial p. H 80 60 40 20 0 100 80 60 40 20 0 3 4 5 6 7 Dosage (mg) 8 9 12 15 0 5 10 15 30 60 Time (minutes) A. Afsar, L. M. Harwood, M. J. Hudson, M. E. Hodson and E. J. Shaw, Chem. Comm. , 2014, 50, 7477– 7480.
Synthesis of Immobilized Cy. Me 4 -BTPhen Precursor Problematic Synthetic Steps A. Afsar, D. M. Laventine, L. M. Harwood, M. J. Hudson and A. Geist, Chem. Commun. , 2013, 49, 8534 -8536.
Improved Route to Bromo. Cy. Me 4 BTPhen James Westwood Alyn Edwards
Immobilization of Cy. Me 4 -BTPhen A. Afsar, D. M, L. M. Harwood, M. J. Hudson, P. Distler and J. John, Chem. Commun. , 2014, 50, 15082 -15085.
Separation factor Distribution ratio, log 10 Immobilization of Cy. Me 4 -BTPhen: Am(III) / Eu(III) Separation [HNO 3] / M At low [HNO 3] both Am 3+ and Eu 3+ are extracted efficiently with little differentiation. However, with increasing [HNO 3], Eu 3+ is displaced more strongly than Am 3+ such that at 4 M HNO 3, only Am 3+ is retained on the nanoparticles. A. Afsar, D. M, L. M. Harwood, M. J. Hudson, P. Distler and J. John, Chem. Commun. , 2014, 50, 15082 -15085. .
Separation factor Distribution ratio, log 10 Immobilization of Cy. Me 4 BTPhen: Am(III) / Cm(III) Separation [HNO 3] / M max SFAm/Cm = ca. 2 at 4 M HNO 3
Separation factor Distribution ratio, log 10 Solution Phase Am(III) / Cm(III) Separation Cy. Me 4 BTPhen [HNO 3] / M max SFAm/Cm = ca. 1 over whole range of [HNO 3] studied; contact time 60 min.
Separation factor Distribution ratio, log 10 Solution Phase Am(III) / Cm(III) Separation [HNO 3] / M
Separation factor Distribution ratio, log 10 Solution Phase Am(III) / Cm(III) Separation 5 -(4 -hydroxyphenyl)-Cy. Me 4 BTPhen [HNO 3] / M max SFAm/Cm = ca. 5. 5 at 1 M HNO 3; contact time 60 min – and CHON
Achievements and Conclusions Iron oxide (Fe 2 O 3) MNPs coated with silica and functionalized with R 4 BTPhen have the ability to extract various metal ions from aqueous solution probably as 1 : 1 metal : ligand complexes, leading to a totally new extraction profile compared to liquid-liquid extraction systems. This has opened up a whole new range of extraction possibilities leading to very high Am 3+ – Eu 3+ separations that are dependent upon nitric acid concentration. The ability to “fine-tune” the electronic properties of the BTPhen backbone has resulted in solution phase systems that have workable Am 3+ – Cm 3+ selectivities that are dependent upon nitric acid concentration. A scalable synthesis of the Cy. Me 4 BTPhen system has been achieved
Acknowledgements Reading University Chemistry group Dr Michael Hudson* Dr Frank Lewis Dr Dominic Laventine Dr Andy Smith Mr (Dr) Ashfaq Afsar Mr James Westwood Soil science group Support staff Prof Mark Hodson Dr Liz Shaw Mr David Hughes Mr Peter Harris (TEM) Mr Peter Heath (NMR) Mr Radek Kowalczyk (NMR) Mr Martin Reeves (MS) Mrs Ogla Khutoryanskaya (TGA) Mr Nick Spencer (XRD) Mrs Anne Dudley (AA) *Deceased 22/01/16 Manchester University Nuclear Fi. RST DTC Dr Roger Whitehead Dr Clint Sharrad Mr Chad Edwards Extraction studies groups Dr Andreas Geist (KIT-INE Karlsruhe) Prof Jan John (CTU Prague) Mr Petr Distler(CTU Prague)
Group Motto “Never Give Up!” 25
Hofstadter’s Law “It always takes longer than you expect – even when you take account of Hofstadter’s Law” D. R. Hofstadter in Gödel, Escher and Bach, an Eternal Golden Braid p. 152. 26
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