As shown by several groups, nano-sized zerovalent iron (nZVI) particles can alter the reaction pathways by which aqueous chlorinated methanes decompose.  As part of our effort to understand the mechanisms involved, we conducted experiments under anoxic conditions to determine the effect of different solution constituents (presumably adsorbates) on the rate by which nZVI particles are oxidized to form magnetite shells.  Replicate suspensions of TODA RNIP nZVI particles were prepared in deionized-deoxygenated water in the presence of various solutes including natural organic matter (NOM), bis-tris propane (pH 7.2), hydrogen phosphate (pH 7.2), and various small organic molecules, and then incubated at room temperature for periods up to 8 weeks.  Periodically, replicates were flash-dried and reaction progress determined by analysis using micro-X-ray diffraction and transmission electron microscopy.  A substantial inhibiting effect of NOM was observed that scaled with NOM concentration. Experiments with other solutes are in progress and results will be discussed.

Adsorbate effects on aqueous oxidation of nano-sized zerovalent iron particles

239th National Meeting (2010)

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