Fe(II) induced reduction of incorporated U(VI) to U(V) in goethite

DOI: 10.1021/acs.est.1c06197

Authors: Olwen Stagg (The University of Manchester) , Katherine Morris (The University of Manchester) , Andy Lam (University of California Davis) , Alexandra Navrotsky (Arizona State University) , Jesús M. Velázquez (University of California Davis) , Bianca Schacherl (Karlsruhe Institute of Technology) , Tonya Vitova (Karlsruhe Institute of Technology) , Jörg Rothe (Karlsruhe Institute of Technology) , Jurij Galanzew (Karlsruhe Institute of Technology) , Anke Neumann (Newcastle University) , Paul Lythgoe (he University of Manchester) , Liam Abrahamsen-Mills (National Nuclear Laboratory) , Samuel Shaw (The University of Manchester)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Environmental Science & Technology , VOL 35

State: Published (Approved)
Published: December 2021
Diamond Proposal Number(s): 21441

Abstract: Over 60 years of nuclear activities have resulted in a global legacy of radioactive wastes, with uranium considered a key radionuclide in both disposal and contaminated land scenarios. With the understanding that U has been incorporated into a range of iron (oxyhydr)oxides, these minerals may be considered a secondary barrier to the migration of radionuclides in the environment. However, the long-term stability of U-incorporated iron (oxyhydr)oxides is largely unknown, with the end-fate of incorporated species potentially impacted by biogeochemical processes. In particular, studies show that significant electron transfer may occur between stable iron (oxyhydr)oxides such as goethite and adsorbed Fe(II). These interactions can also induce varying degrees of iron (oxyhydr)oxide recrystallization (<4% to >90%). Here, the fate of U(VI)-incorporated goethite during exposure to Fe(II) was investigated using geochemical analysis and X-ray absorption spectroscopy (XAS). Analysis of XAS spectra revealed that incorporated U(VI) was reduced to U(V) as the reaction with Fe(II) progressed, with minimal recrystallization (approximately 2%) of the goethite phase. These results therefore indicate that U may remain incorporated within goethite as U(V) even under iron-reducing conditions. This develops the concept of iron (oxyhydr)oxides acting as a secondary barrier to radionuclide migration in the environment.

Journal Keywords: Fe(II); U(VI,V); iron (oxyhydr)oxides; XAS; HR-XANES

Subject Areas: Materials, Chemistry, Environment


Instruments: I20-Scanning-X-ray spectroscopy (XAS/XES)

Other Facilities: CAT-ACT at KIT

Added On: 13/12/2021 08:56

Discipline Tags:

Desertification & Pollution Earth Sciences & Environment Radioactive Materials Mineralogy Chemistry Materials Science Nuclear Waste Inorganic Chemistry Geology

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS)