Page 328 - Environmental Nanotechnology Applications and Impacts of Nanomaterials

Nanomaterials for Groundwater Remediation 313

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Figure 8.8 GeoProbe injection of nanoparticles into the subsurface. Multiple
injection points along the probe can provide a zone of influence over a portion of
or the entire vertical section of the contaminated area. Photo is courtesy of
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GeoProbe Systems, Inc., Salina, Kansas.

nanoiron (Saleh et al. 2007; Schrick et al. 2004) to a few meters for
carbon nanomaterials under typical groundwater conditions (Lecoanet
et al. 2004; Lecoanet and Wiesner 2004). This has prompted the use of
supports such as hydrophilic carbon or polyacrylic acid to enhance the
transport of nanoiron (Schrick et al. 2004), the use of surfactant micelles
to deliver nanoiron directly to entrapped NAPL (Quinn et al. 2005), or
adsorbed polymers to improve transport distances and target entrapped
DNAPL (Saleh et al. 2007). The reasons for limited transport and the
need for advanced delivery vehicles are addressed here.
Investigations of the transport and fate of colloids (micron and sub-
micron particles) in the environment has been extensively studied
for decades, as these processes are critical to understanding deep bed