JRP CALL information
Supported By

European Commission

Short description of the work

Using the TALISMAN pooled facilities at KIT-INE, we were able to study the extraction capabilities and coordination chemistry of a family of newly designed ligands based on DTPA and EDTA appended with amino acids using nuclear magnetic resonance (NMR) and time resolved laser induced fluorescence spectroscopy (TRLIFS) spectroscopies. The precursors are readily available and affordable, allowing effective separation of trivalent lanthanides and actinides in the reprocessing of spent nuclear fuel. The process we have developed is a simplified approach to lanthanide/actinide separations based on a modified TALSPEAK process. In our hands, the polyaminocarboxylates DTPA and EDTA are appended with a series of amino acids that act to self-buffer the solution and lower the pH of the extraction processes to that of the pKa of the amino acids themselves (ca. 1.5). Our preliminary results show that the ligands show high selectivity for An(III) over Ln(III) with separation factors over 100, importantly without the need for an additional buffer agents or modifiers. The pooled facilities enabled us to examine the separation behavior of four ligands containing representative amino acids; DTPA-bis-alanine, DTPA-bis-histidine, EDTA-bis-alanine and EDTA-bis-histidine. In addition to the extraction experiments over the pH range 1-3 with all ligands and americium(III) and lanthanide(III), we were able to study the coordination environment of all ligands with americium(III) by NMR spectroscopy and that of the curium(III) derivatives by TRLIFS. Both these spectroscopic techniques showed that all the ligands possess fast complexation kinetics and verified the 1:1 binding motif of the chelates in solution, additionally giving information on the relative stabilities of the curium(III) complexes.

 

Main visitor contact data
Name: Louise Natrajan
Organisation: The University of Manchester

JRP Identification
JRP nr: TALI-C04-16
JRP title: Development of Simplified Separation Systems Based on Amino Acid Appended DTPA Derivatives for trivalent Actinide/Lanthanide Separations that Self‐Buffer at Low pH
JRP scope: Scope 1: Actinide separation chemistry

Visited Associated Pooled Facility
Visited APF during the stay: KIT-INE - Laboratories
Name of the APF Contact Person: Andreas Geist

Other APF and organisation involved in the JRP
Other organisations involved:
Other APF involved in the project:

Description of the work done at the associated pooled facility
Start date of the stay: 5/18/2015
End date of the stay: 6/12/2015
Quantity of access: 40
Access Unit: Days

Other APF visitors of the JRP during the stay
Visitor 2: Dr Jennifer Jones
Visitor 3: Miss Helen Victoria Stafford