We studied the aging of Fe0-core/oxide-shell nanoparticles in water with a focus on changes in (i) the composition and structure of the particles (by XRD, TEM, XPS, and bulk Fe0 content), and (ii) the reactivity of the particles (by carbon tetrachloride reaction kinetics, electrochemical corrosion potentials, and H2 production rates). The results show that nano-Fe0 become more reactive between 0 and ~2 days exposure to water, and then gradually it loses reactivity over the next few hundred days. The behavior of unaged nano-Fe0 in our laboratory experiments may be similar to that in field-scale applications for source-zone treatment due to the short reaction times involved. However, nano-Fe0 that has been aged in water for >3 days acquires properties that are relatively stable over weeks or even months.
Revised: April 7, 2011 |
Published: November 1, 2009
Citation
Tratnyek P.G., V. Sarathy, J. Nurmi, D.R. Baer, J.E. Amonette, C. Chun, and R.L. Penn, et al. 2009.Aging of Iron Nanoparticles in Water: Effects on Structure and Reactivity. In International Perspectives on Environmental Nanotechnology: Applications and Implications; EPA 905/R-09/032, 2, 193-196. Washington, District Of Columbia:Environmental Protection Agency.PNNL-SA-61980.