Insights on uranium uptake mechanisms by ion exchange resins with chelating functionalities: chelation vs anion exchange

DOI: 10.1016/j.cej.2019.123712

Authors: James T. M. Amphlett (The University of Sheffield; The University of Manchester; Korea Advanced Institute of Science and Technology (KAIST)) , Sungyeol Choi (Korea Advanced Institute of Science and Technology (KAIST)) , Stephen A. Parry (Diamond Light Source) , Ellen M. Moon (Deakin University) , Clint A. Sharrad (The University of Manchester) , Mark D. Ogden (The University of Sheffield)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Chemical Engineering Journal

State: Published (Approved)
Published: December 2019
Diamond Proposal Number(s): 12643

Abstract: X-ray absorption fine structure analysis has been successfully used to determine the coordination environment and therefore uptake mechanism towards the uranyl cation for a selection of commercially available ion exchange resins in non-saline and saline conditions ([Cl−] = 22.7 g L−1, 0.64 M) similar to those found in sea water. The resins tested were Purolite S985, S910 and S957, Dowex M4195, Ps-EDA, Ps-DETA and Ps-PEHA, which contain polyamine, amidoxime, mixed sulfonic/phosphonic acid, bispicolylamine, ethylenediamine, diethylenetriamine and pentaethylenehexamine functional groups, respectively. Purolite S910 and S957 were both found to extract the uranyl cation through a chelation mechanism. The uranium coordination environment on uranyl loaded Purolite S910 was found to be either tetra- or hexa-coordinate in the equatorial plane, with a 2:1 ratio of amidoxime:uranium in the fit suggesting either monodentate or η2 coordination by two amidoxime groups. The uranium environment for uranyl loaded Purolite S957 was found to be tetra-coordinate in the equatorial plane, with both sulfonic and phosphonic acid groups being involved in sorption. The presence of chloride in the loading solution had no effect on the uranyl coordination environment observed on any of the resins. In contrast, Dowex M4195, Purolite S985, Ps-EDA, Ps-DETA and Ps-PEHA exhibited an anion exchange mechanism for uranyl uptake as the corresponding extended X-ray absorption fine structure (EXAFS) data best fit a [UO2(SO4)3]4− structure.

Journal Keywords: Ion exchange; Chelation; EXAFS; Uranium Speciation

Subject Areas: Chemistry, Engineering, Energy


Instruments: B18-Core EXAFS

Added On: 10/12/2019 11:03

Discipline Tags:

Radioactive Materials Chemistry Materials Science Chemical Engineering Engineering & Technology

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS) Extended X-ray Absorption Fine Structure (EXAFS)