Fig. 8: Conceptual model of U(VI) reduction by magnetite.
From: Nanoscale mechanism of UO2 formation through uranium reduction by magnetite
Magnetite particles are indicated in gray and uranium species in yellow. The reaction starts with rapid adsorption of aqueous U(VI) species onto the magnetite surface. Adsorbed U(VI) is reduced to U(V) and U(IV) species. While U(V) remains on the magnetite surface, U(IV) precipitates out as uraninite nanoparticles that self-assemble into nanowires structures anchored to the magnetite surface. Nanowires continue to grow while reduction proceeds. Eventually, crystal growth and coalescence lead to the collapse of nanowires into UO2 nanoclusters in which nanoparticles display a preferred orientation.
