NANOSCALE SIZE EFFECTS ON URANIUM(VI) ADSORPTION AND REDUCTION BY IRON(II) ON HEMATITE NANOPARTICLES

摘要

Hematite (α-Fe2O3) nanoparticles occur naturally in the environment and can exert strong controls on the biogeochemical processes of environmental systems due to their reactive surfaces and high specific surface areas. Uranium(VI) is a priority contaminant in soil and groundwater at many sites. Dissolved U(VI) (UO_2~(2+)) can be adsorbed to the surface of hematite nanoparticles and reduced to insoluble U(IV) by surface-bound Fe(II). Iron-reducing bacteria can catalyze surface-mediated reduction by regenerating surface-associated Fe(II). This active nanosystem can provide the basis for improved environmental remediation technologies. Before potential application of these technologies, a better understanding of the effects of particle size on hematite surface reactivity is needed.