Environmental Engineering Reference
In-Depth Information
CHAPTER 4
Huy Quang Nguyen, Zhihua Liang, and Zhiqiang Hu
4.1
Introduction
Chlorinated organic compounds are persistent in the environment. Chlorinated
aliphatic hydrocarbons such as trichloroethylene (TCE) and perchloroethylene (PCE)
serve as great organic solvents in industry. Chlorinated aromatic hydrocarbons-
monocyclic and polycyclic compounds such as polychlorinated biphenyls (PCBs) are
classified as highly bioaccumulative pollutants even though PCB was banned in the
1970s due to the high toxicity of most PCB congeners and mixtures. Other chlorinated
organic compounds including chlorinated biocides, phenols, dioxins, and furans are
often found into the environment. Abiotic and biotic methods are available to degrade
and remove these chlorinated organic pollutants from contaminated groundwater or
soils. With the development of emerging nanotechnology, it becomes more evident that
nano-size iron particles have great potential in rapidly and effectively reducing and
removing the persistent chlorinated organic compounds in the environment. The
objective of this chapter is to overview the applications of nanoparticles for removal of
chlorinated organic solvents, such as PCE, TCE, PCBs, from the environment
.
4.2
Overview of Chlorinated Organic Solvents
4.2.1 Origins and Environmental Fate
Both TCE and PCE are effective solvents and have been widely used as a
degreaser for metal parts. Since its large-scale production in the 1920s, TCE was also
used as a volatile gas anesthetic from the 1930s through the 1960s. These aliphatic
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