Optimization of Cation Exchange for the Separation of Actinium-225 from Radioactive Thorium, Radium-223 and Other Metals
1
Isotope Production Laboratory, Collider-Accelerator Division, Brookhaven National Laboratory, Upton, NY 11973, USA
2
Department of Biology, Chemistry, and Geoscience, Fairmont State University, Fairmont, WV 26554, USA
3
Department of Chemistry, University at Buffalo, the State University of New York, Buffalo, NY 14260, USA
4
Department of Chemistry, Elizabeth City State University, Elizabeth City, NC 27909, USA
*
Author to whom correspondence should be addressed.
†
These authors contributed equally to this work.
‡
Present affiliation: Bryna Torre at University of Buffalo School of Medicine, Bryan Foley at Texas A&M University, 400 Bizzell St, College Station, TX 77843, USA.
Academic Editors: Licia Uccelli, Alessandra Boschi and Petra Martini
Molecules 2019, 24(10), 1921; https://doi.org/10.3390/molecules24101921
Received: 11 March 2019 / Revised: 15 May 2019 / Accepted: 16 May 2019 / Published: 18 May 2019
(This article belongs to the Special Issue New Trends in Production and Applications of Metal Radionuclides for Nuclear Medicine)
Actinium-225 (225Ac) can be produced with a linear accelerator by proton irradiation of a thorium (Th) target, but the Th also underdoes fission and produces 400 other radioisotopes. No research exists on optimization of the cation step for the purification. The research herein examines the optimization of the cation exchange step for the purification of 225Ac. The following variables were tested: pH of load solution (1.5–4.6); rinse steps with various concentrations of HCl, HNO3, H2SO4, and combinations of HCl and HNO3; various thorium chelators to block retention; MP50 and AG50 resins; and retention of 20–45 elements with different rinse sequences. The research indicated that HCl removes more isotopes earlier than HNO3, but that some elements, such as barium and radium, could be eluted with ≥2.5 M HNO3. The optimal pH of the load solution was 1.5–2.0, and the optimized rinse sequence was five bed volumes (BV) of 1 M citric acid pH 2.0, 3 BV of water, 3 BV of 2 M HNO3, 6 BV of 2.5 M HNO3 and 20 BV of 6 M HNO3. The sequence recovered >90% of 225Ac with minimal 223Ra and thorium present.
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Keywords:
Lanthanum; Rhodium; AG50; MP50; fission products; Actinium-225; 225Ac; 223Ra; 227Th; thorium
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MDPI and ACS Style
Fitzsimmons, J.; Foley, B.; Torre, B.; Wilken, M.; Cutler, C.S.; Mausner, L.; Medvedev, D. Optimization of Cation Exchange for the Separation of Actinium-225 from Radioactive Thorium, Radium-223 and Other Metals. Molecules 2019, 24, 1921.
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