Application of Zero-valent Iron Nanoparticles for Environmental Clean Up - Advanced Materials for Agriculture, Food and Environmental Safety - page 407

organic carbon (VOCs), tetra-, tri- and di-chloroethene. At er six weeks of
nanoparticle injection, over a 90% reduction was observed in concentra-
tion of VOCs and the concentration of terta-, tri-, di-chloroethene were
found below groundwater quality standards [103].
Quinn et al. [104] and O'Hara et al. [105] reported high dechlorina-
tion ei ciencies for DNALP contaminant trichloroethylene (TCE) during
a i eld-scale demonstration of emulsii ed nFe 0 at Cape Canaveral Air Force
Station, Florida, USA. A pilot-scale demonstration of bimetallic nanopar-
ticles has also been carried out at Jacksonville and Lakehurst (USA) for
reduction of TCE. In comparison to emulsii ed nFe 0 , bimetallic nanoparti-
cles were found less ei cient, possibly due to early passivation of nanopar-
ticle or use of an insui ciently high ratio of iron and soil to generate
reducing environment in the aquifer [14]. In another pilot-scale study, 150
gallons of 0.2 g/L Pd/nFe 0 were injected into 50-t deep, aquifer contami-
nated with chlorinated ethenes (perchloroethylene (PCE) and trichloro-
ethylene (TCE) and polychlorinated biphenyls (PCBs)). One month later,
another 150 gallons 1.0 g/L Fe-Pd (CMC = 0.6 wt%, Pd/Fe = 0.1 wt%) was
injected into the same aquifer at an injection pressure <5 psi. As per results,
rapid degradation of PCE and TCE was observed in the i rst week of injec-
tion, however the reducing power of nFe 0 was exhausted at er 2 weeks. To
counteract this limitation CMC-stabilized nFe 0 was used, which not only
enhanced the dechlorination, but also appeared to boost in situ biological
dechlorination reactions. h is study proposed that CMC-stabilized nFe 0
facilitated the early stage abiotic degradation and at the same time acted
as a source of carbon for biotic processes, thereby sustaining the biological
degradation of chlorinated ethenes in subsurface [106]. Singh et al. [107]
studied remediation of Cr(VI) with nFe 0 in a tannery waste-contaminated
site located in Rania, Kanpur, India. h e site has been used for many years
as a dumping ground for wastes generated from leather tanneries and basic
chrome sulphate industries. h ey investigated the remediation process in
constructed soil windrows and reported ~99% reduction over reaction
period of 50 days.
Field-scale commercial application of nFe 0 has become common in
the United States, but there have been only a few i eld-scale projects
carried out in Europe so far. Among them, Bornheim, Germany, was the
i rst contaminated site where nFe 0 had been applied for full-scale reme-
diation. h e site was contaminated with several tons of tetrachloroeth-
ene (PCE) from an industrial laundry/dry cleaner. h e contaminant was
spread over several square kilometers of area down to a depth of 20 m.
Injection of one ton of stabilized nFe 0 along with 2 tons of microsized
nFe 0 , ef ectively reduced 90% of the PCE concentration initially present.