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Redox reactions of Fe(III) and AHA in nitric acid solutions in the context of an advanced purex process: 14th International Nuclear Fuel Cycle Conference, GLOBAL 2019 and Light Water Reactor Fuel Performance Conference, TOP FUEL 2019

Research output: Contribution to conference - Without ISBN/ISSN Conference paper

Published
Publication date1/01/2020
Number of pages10
Pages983-992
Original languageEnglish
Event14th International Nuclear Fuel Cycle Conference, GLOBAL 2019 and Light Water Reactor Fuel Performance Conference, TOP FUEL 2019 - The Westin Seattle, Seattle, United States
Duration: 22/09/201926/09/2019
http://globaltopfuel.ans.org/

Conference

Conference14th International Nuclear Fuel Cycle Conference, GLOBAL 2019 and Light Water Reactor Fuel Performance Conference, TOP FUEL 2019
CountryUnited States
CitySeattle
Period22/09/1926/09/19
Internet address

Abstract

Simple hydroxamic acids such as acetohydroxamic acid (AHA) have the ability to strip Pu(IV) and Np(IV) from tri-butyl phosphate into nitric acid by forming strong complexes with these ions. AHA has thus been identified as a suitable reagent for the control of Pu and Np in advanced separation processes for nuclear fuel reprocessing, such as the Advanced PUREX (Plutonium URanium EXtraction) and the Grouped ActiNide Extraction (GANEX) recycle processes. It is known that both free and complexed AHA undergo an acid catalysed hydrolysis reaction at low pH to form hydroxylamine (NH2OH) and acetic acid (CH3COOH), but the kinetics of this process is not fully understood in these systems. In this work, we have used Fe(III) as a non-active analogue for Pu(IV) and Np(IV) to investigate the hydrolysis kinetics of both free and complexed AHA by utilizing ion chromatography to measure the ingrowth of the acetate ion over time. In contrast to previous studies, our results show that the rate of AHA hydrolysis is inhibited in the presence of Fe(III). From our data we obtain an Arrhenius factor (A) of 1.25 x 10 11 dm 3.mol -1.s -1 and 3.71 x 10 18 dm 3.mol -1.s -1, and an activation energy (Ea) of 89.0 kJ.mol -1 and 137.4 kJ.mol -1 for the hydrolysis of the free and complexed AHA respectively.

Bibliographic note

Conference code: 157481 Export Date: 19 March 2020 Correspondence Address: Jones, S.; Engineering Department, Lancaster University, Gillow Avenue, United Kingdom; email: s.buckmaster@lancaster.ac.uk Funding details: Engineering and Physical Sciences Research Council, EPSRC Funding text 1: The authors thank the UK Engineering & Physical Sciences Research Council (EPSRC) Next Generation Nuclear Centre for Doctoral Training and the Lloyd’s Register Foundation (LRF, award no. G0025) for support for SB. All work was conducted in Lancaster University’s UTGARD Lab (Uranium / Thorium beta-Gamma Active R&D Lab), a National Nuclear User Facility also supported by the EPSRC. The authors also thank the LRF for support for CB. The Lloyds Register Foundation is an independent charity that supports the advancement of engineering-related education, and funds research and development that enhances safety of life at sea, on land and in the air. References: Taylor, R.J., May, I., Wallwork, A.L., Denniss, I.S., Hill, N.J., Galkin, B.Ya., Zilberman, B.Y., Fedorov, Yu.S., The applications of formo- And acetohydroxamic acids in nuclear fuel reprocessing (1998) J. Alloys Compd., 271-273, pp. 534-537; Tkac, P., Precek, M., Paulenova, A., Redox reactions of Pu(IV) and Pu(III) in the presence of acetohydroxamic acid in HNO3 solutions (2009) Inorg. Chem., 48, pp. 11935-11944; Carrott, M.J., Fox, O.D., Le Gurun, G., Jones, C.J., Mason, C., Taylor, R.J., Andrieux, F.P.L., Boxall, C., Oxidation-reduction reactions of simple hydroxamic acids and plutonium(IV) ions in nitric acid (2008) Radiochim. Acta, 96, pp. 333-343; Carrott, M.J., Bell, K., Brown, J., Geist, A., Gregson, C., Heres, X., Maher, C., Taylor, R.J., Development of a new flowsheet for co-separating the transuranic actinides: The "EURO-GANEX" process (2014) Solvent Extr. Ion Exch., 32 (5), pp. 447-467; Barney, G.S., A kinetic study of the reaction of plutonium(IV) with hydroxylamine (1976) Journal of Inorganic and Nuclear Chemistry, 38 (9), pp. 1677-1681; Andrieux, F.P.L., Boxall, C., Steele, H.M., Taylor, R.J., The Hydrolysis of Hydroxamic Acid Complexants in the Presence of Non-oxidizing Metal Ions 3: Ferric ions at elevated temperatures (2014) J. Solution Chem., 43, pp. 698-1622; Bengtsson, G., Fronӕus, S., Bengtsson-Kloo, L., The kinetics and mechanism of oxidation of hydroxylamine by iron(III) (2002) J. Chem.Soc., Dalton Trans., pp. 2548-2552; Schafer, H., Laubli, M., Dorig, R., Ion chromatography - Theory - Columns and eluents Metrohm; Meyer, V.R., (2010) Practical High-Performance Liquid Chromatography, , Fifth ed. Wiley; Andrieux, F.P.L., Boxall, C., Taylor, R.J., The Hydrolysis of Hydroxamic Acid Complexants in the Presence of Non-oxidizing Metal Ions 1: Ferric ions (2007) J. Solution Chem., 36 (10), pp. 1201-1217; Andrieux, F.P.L., Boxall, C., May, I., Taylor, R.J., The hydrolysis of hydrozamic acid complexants in the presence of non-oxidising metal ions 2: Neptunium (IV) ions (2008) J. Solution Chem., 37 (2), pp. 215-232; Taylor, R.J., Denniss, I.S., May, I., Hydroxamic acids - Novel reagents for advanced purex processes (2000) Atalante 2000, Scientific Research on the Back-End of the Fuel Cycle for the 21st Century, , Avignon; Chung, D.Y., Lee, E.H., Kinetics of the hydrolysis of acetohydroxamic acid in a nitric acid solution (2006) Journal of Industrial and Engineering Chemistry, 12 (6), pp. 962-966; Edwards, S., Andrieux, F., Boxall, C., Sarfield, M., Taylor, R., Woodhead, D., Neptunium(IV)hydroxamate complexes: Their speciation, and kinetics and mechanism of hydrolysis (2019) Dalton Trans, 48, p. 673