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Title: Complexation of Curium(III) with DTPA at 10–70 °C: Comparison with Eu(III)–DTPA in Thermodynamics, Luminescence, and Coordination Modes

Separation of trivalent actinides (An(III)) from trivalent lanthanides (Ln(III)) is a challenging task because of their nearly identical chemical properties. Diethylenetriaminepentaacetate (DTPA), a key reagent used in the TALSPEAK process that effectively separates An(III) from Ln(III), is believed to play a critical role in the An(III)/Ln(III) separation. However, the underlying principles for the separation based on the difference in the complexation of DTPA with An(III) and Ln(III) remain unclear. In this work, the complexation of DTPA with Cm(III) at 10-70 ºC was investigated by spectrophotometry, luminescence spectroscopy, and microcalorimetry, in conjunction with computational methods. The binding strength, the enthalpy of complexation, the coordination modes, and the luminescence properties are compared between the Cm(III)-DTPA and Eu(III)-DTPA systems. The experimental and computational data have demonstrated that the difference between Cm(III) and Eu(III) in the binding strength with DTPA can be attributed to the stronger covalence bonding between Cm(III) and the nitrogen donors of DTPA.
Authors:
 [1] ;  [2] ;  [3] ;  [1]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  2. Stanford Univ., CA (United States). Stanford Research Computing Center
  3. Idaho National Lab. (INL), Idaho Falls, ID (United States)
Publication Date:
OSTI Identifier:
1182218
Report Number(s):
INL/JOU--14-33410
Journal ID: ISSN 0020-1669; TRN: US1500193
DOE Contract Number:
AC07-05ID14517
Resource Type:
Journal Article
Resource Relation:
Journal Name: Inorganic Chemistry; Journal Volume: 54; Journal Issue: 4
Publisher:
American Chemical Society (ACS)
Research Org:
Idaho National Laboratory (INL), Idaho Falls, ID (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; DTPA; CURIUM; LUMINESCENCE; EUROPIUM; TALSPEAK PROCESS; BINDING ENERGY; ENTHALPY; THERMODYNAMICS; CALORIMETRY; COVALENCE; SPECTROPHOTOMETRY; SPECTROSCOPY; TEMPERATURE RANGE 0273-0400 K; SEPARATION PROCESSES; CURIUM COMPLEXES COMPLEXATION