Application of Zero-valent Iron Nanoparticles for Environmental Clean Up - Advanced Materials for Agriculture, Food and Environmental Safety - page 385

of environmental clean up. In the past two decades, a nanoparticles-based
remediation approach has gained signii cant achievements in the i eld of
environmental clean up, suggesting its potential as a good alternative to the
current practices of site remediation. As compared to conventional treat-
ment technologies such as pump and treat, soil l ushing, incineration, etc.,
nanoparticles of er an ef ective, economic and time-ei cient technology.
h eir extremely small size and excellently high surface area make them an
ei cient remediation tool for both in situ and ex situ application. Among
several of the nanoparticles, zero-valent metal nanoparticles show good
ei ciency for reducing organic and inorganic contaminants. For instance,
Zn 0 , Cu 0 , Fe 0 , Mg 0 , Pd 0 , etc., have been reported for the removal of various
contaminants from soil, sediments and groundwater [1-3]. Being inexpen-
sive and environmentally benign, zero-valent iron (Fe 0 ) is the most widely
studied nanoparticle for the treatment of environmental contaminants.
h e reducing ability of Fe 0 was i rst demonstrated in 1994 by Gillham and
O'Hannesin [4] while studying the reduction of chlorinated compounds.
Since then, a huge ef ort has been made to test the potential of Fe 0 for
reducing toxic/hazardous substances such as chlorinated hydrocarbons,
chlorinated solvents, pesticides, dyes, heavy metals, etc., as indicated by
the number of related studies published at er 1994 [5-10].
With the introduction of nanotechnology in the area of environmental
clean up, attempts have been made to explore the potential of nanoscale
zero-valent iron (hereat er referred to as nFe 0 ) for treatment of environ-
mental toxicants. h e combination of nanosize ef ect and excellent reduc-
ing capabilities of Fe 0 has resulted in the emergence of a very powerful
remediation tool for reducing the burden of toxic/hazardous wastes from
the environment. Zero-valent iron has been successfully applied as reduc-
tant to degrade chlorinated aliphatic and alicyclic compounds, chlorinated
solvents, nitroaromatic compounds, textile dyes, chlorinated pesticides,
heavy metals, etc. [11-15]. Two potential advantage of nFe 0 over their micro
or macro counterparts is that nFe 0 can be injected deep into groundwater
and aquifers to treat contaminated plume and that the reaction kinetics of
contaminant degradation is much higher. h e appealing traits of this tech-
nology have led the scientii c and engineering community to rapidly adopt
it as a new alternative tool for remediation. h e performance of nFe 0 has
been displayed by several investigators in batch-scale studies. Numerous
i eld-scale demonstrations have also been tested and completed in the past
few years.
Apart from their fruitful applications of nFe 0 , there is also a wide debate
among the scientii c community, government bodies and public, regarding
its toxicity, fate and behavior in the environment and its potential impact