GEOC 117 |
| Magnetite (Fe3O4) nanoparticles in anoxic subsurface environments have the potential to participate in the reduction of halogenated contaminants. The aggregation and transformation of magnetite have to be considered in order to understand and quantify the reactivity of these nanoparticles with organohalides. In this work, we quantified the aggregation behavior and kinetics of magnetite nanoparticles as a function of pH and ionic strength. The rate of formation and the fractal dimension of the nanoaggregates were assessed using dynamic light scattering spectroscopy. Variations in particle morphology and size distribution were evaluated using transmission electron microscopy (TEM). Changes in the surface charge of the nanoparticles were determined using potentiometric acid-base titrations. We characterized magnetite nanoparticle reactivity with a model contaminant, carbon tetrachloride (CCl4), in anoxic water and simultaneously evaluated particle conversion to maghemite. We will present how the oxidation of magnetite to maghemite affects particle aggregation and halogenated contaminant reduction capability. |
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The Structure and Reactivity of Nanoparticles in the Environment
1:30 PM-4:00 PM, Wednesday, 13 September 2006 Moscone Center -- Room 262, Oral
Division of Geochemistry |