Zero-valent iron effectively dehalogenates chlorinated contaminants such as trichloroethylene (TCE). However, these sparingly soluble contaminants are difficult to access for effective treatment because of the poor transport properties of iron particles in the subsurface. This makes the effective in situ remediation of contaminated soil and groundwater difficult to achieve. The transport of iron nanoparticles through columns of saturated model soils taken from different areas of the USDA soil textural triangle was studied to understand the interactions of the particles with the complex matrix of natural soils. Unmodified iron nanoparticles were efficiently filtered by the soil packed columns through an interception mechanism, because the particles rapidly aggregate. However, by coating the particles with an anionic polymer or hydrocolloid, the aggregation was greatly reduced. The anionic support materials, i.e., hydrophilic carbon and poly(acrylic acid), i.e., substantially lowered the sticking coefficient of iron nanoparticles to the soil matrix. The addition of anionic hydrocolloids and polyelectrolytes to the iron suspensions affected particle transport through blocking and macromolecular crowding effects. The reactivity of the particle suspensions was studied using highly crystalline and polycrystalline iron nanoparticles. TCE dehalogenation by iron particles is a slow process, but adding a second, catalytic metal such as palladium, to a suspension of polycrystalline nano-iron particles significantly accelerates the reaction. This is an abstract of a paper presented at the 228th ACS National Meeting (Philadelphia, PA 8/22-26/2004).
|Original language||English (US)|
|Number of pages||2|
|Journal||ACS, Division of Environmental Chemistry - Preprints of Extended Abstracts|
|State||Published - Dec 1 2004|
|Event||228th ACS National Meeting - Philadelphia, PA, United States|
Duration: Aug 22 2004 → Aug 26 2004
All Science Journal Classification (ASJC) codes