Environmental Engineering Reference
In-Depth Information
CHAPTER 8
Sita Krajangpan, Bret J. Chisholm, Harjyoti Kalita, and
Achintya N. Bezbaruah
8.1
Introduction
Zero-valent iron (ZVI)-based remediation is an attractive treatment option as iron
is inexpensive, non-toxic and environmentally compatible. Nanoparticles are attractive
for remediation of various contaminants because of their unique physiochemical
properties (Zhang, 2003, 2005)
.
Reactivity of the nanoparticle increases with an increase
in surface area (Gotpagar et al., 1997; Li et al., 2003). In recent years, microparticles
(mZVI), iron filings and ZVI nanoparticles (nZVI) have been used for the removal of
various groundwater contaminants including chlorinated compounds (Matheson and
Tratnyek, 1994; Boronina et al., 1995; Orth and Gillham, 1996; Roberts et al., 1996;
Campbell et al., 1997; Liang et al., 1997; Tratnyek et al., 1997; He and Zhao, 2005; Tee
and Bhattacharyya, 2005; Huang and Zhang, 2006; Liu and Lowry, 2006; Cheng et al.,
2007), pesticides (Singh et al., 1998; Feitz et al., 2005; Joo and Zhao, 2008; Thompson,
2008), heavy metals (Boronina et al., 1995; Powell et al., 1995; Roberts et al., 1996;
Blowes et al., 1997; Fiedor et al., 1998; Ponder et al., 2000; Alowitz and Scherer, 2002),
nitrate (Huang et al., 2003; Huang and Zhang, 2005; Bezbaruah et al., 2008), and
explosives (Gregory et al., 2004; Oh et al., 2005) in water. The typical mode of
chlorinated contaminant degradation by ZVI is reductive dehalogenation (Matheson and
Tratnyek, 1994), as shown below (Eq. 1).
R-Cl + Fe
0
(s) + H
+
Æ
Fe
2+
+ R-H + Cl
-
(1)
Due to their small particle size (< 100 nm, Wang and Zhang, 1997) and high
reactivity, nZVI have also been used in the remediation of contaminated soils (Martin et
al., 2008), sediments (Zhang and Frankenberger, 2006), and biosolids (Li et al., 2007).
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