Nanoscale zero-valent iron particles for the remediation of plutonium and uranium contaminated solutions

In the current work the uptake of plutonium onto nanoscale zero-valent iron nanoparticles (nZVI) under anoxic conditions has been investigated. A uranyl solution was also studied under similar geochemical conditions to provide a comparative dataset. Following nZVI addition, a rapid and significant decrease in aqueous actinide concentration was recorded for both systems. The removal rate recorded for plutonium was slower, with 77% removal recorded after 1 h of reaction, compared to 99% recorded for uranium. Low aqueous contaminant concentrations (<25%) were then recorded for both systems until the end of the 7 day reaction period. XPS confirmed contaminant uptake onto the nZVI. For the plutonium system, the recorded photoelectron spectra exhibited Pu 4f lines centred at similar to 439 and similar to 427 eV, characteristic of Pu4+ and implying that chemical reduction of the sorbed plutonium had occurred, ascribed to the formation of PuO2. Similarly, with the U-system, the recorded U 4f photoelectron peaks were centred at energies of similar to 380 and similar to 391 eV, characteristic of U4+ in UO2. Results provide clear evidence that nZVI may be used as an effective material for the removal of plutonium from contaminated waters. (C) 2014 Elsevier B.V. All rights reserved.