Abiotic U(VI) Reduction by Biogenic Mackinawite

Biogenic mackinawite (FeS) produced by Shewanella putrefaciens CN32 is submicron in size but nanosized in one dimension (film-like morphology)
Biogenic FeS is very reactive evident by its propensity to reduced U(VI) and rapid oxidation to form lepidocrocite upon exposure to air.
U(VI) reduction is observed in the pasteurized control indicative of a non-enzymatic redox process.
XAS and nanodiffraction techniques (bulk and nanoscale analyses) confirm the formation of UO2.
UO2 particles are nanoparticulate measuring c.a. 2.5 nm in size.
The present work suggests that a remediation strategy could potentially incorporate subsurface abiotic redox interactions between biogenic Fe(II)-bearing minerals such as mackinawite & contaminant U(VI) to immobilize U as UO2 – an in-situ waste form.