Iron nanoparticles could lead to more effectives carbon tetrachloride cleanup
Researchers at Pacific Northwest National Laboratory,
the University of Minnesota and Oregon Health and
Science University discovered that not all iron nanoparticles
are created equal. Some, in fact, may be especially
useful for cleaning up groundwater contaminated with
carbon tetrachloride. In the past, carbon tetrachloride was used for various
purposes by industry and government. Today, it is found
in the soil and groundwater at sites around the country.
Exposure to high levels of this chemical can damage the liver,
kidneys and nervous system.
“Nanoparticles could find use in remediating deep
inaccessible groundwater plumes, where other remediation
technologies cannot be used cost-effectively,” said James
Amonette, PNNL senior research scientist.
When carbon tetrachloride reacts with iron particles, the
carbon tetrachloride breaks apart. Some of the products that
can be produced are harmful, such as chloroform. Others are
completely benign, such as water. The researchers’ challenge was to figure out how to tip the balance of this reaction to the
safest possible products.
The research team characterized iron nanoparticles from a
wide variety of sources. They discovered that one type of iron
nanoparticle in particular produced much less chloroform
than the other particles.
Then, the team determined the specific properties
of this type of nanoparticle to understand why carbon
tetrachloride followed the more benign reaction path. The
team characterized the particles using x-ray diffraction and
x-ray photoelectron spectroscopy in DOE’s Environmental
Molecular Sciences Laboratory. At OHSU, the researchers
performed electrochemical studies using an electrode designed
especially for nanoparticles.
Based on the results of this fundamental research, the
team believes they have identified the key contributors to
chloroform formation. This new information could be used
to help select and design iron nanoparticles for future carbon
tetrachloride remediation efforts.