transported in the groundwater over large distances from the point of introduction. In
recent times, the number of real applications of nZVIs is rapidly growing. PARS
Environmental Inc. estimated the potential costs of remediation of land polluted with
TCE and perchloroethylene (PCE) in a production plant in New Jersey (Karn et al.
2009). Application of the pump and treat method was estimated to cost around
4,160,000 USD, and the permeable reactive barrier (PRB) method at
2,200,000 USD, while the estimated cost of nanotechnology with nZVI was
450,000 USD, a saving of around 80–90% compared to the pump and treat method.
The use of nanotechnology not only reduces operating costs but also reduces the
time for which employees are exposed to the contamination occurring on the site of
the land being reclaimed. Zhang (2003) noted a 99% reduction in the level of TCE
within a few days after use of nZVI.
The sorption of pollutants, mainly heavy metal ions, by nanomaterials depends to
a large extent on environmental conditions (Wu et al. 2019). Lv et al. (2012)
demonstrated that sorption of Cr(VI) by nZVI-Fe 3 O 4 rises to 96.4% within 2 h.
Temperature may have an influence on the rate of removal of pollutants by changing
the energy in the reaction system. Xiong et al. (2014) proved that sorption of Cr
(VI) by the composite γ-Fe 2 O 3 /C@HKUST-1 was more favorable at higher
temperatures. Under neutral pH conditions, nanomaterials are more effective at
removing heavy metal ions, thanks to surface coordination, electrostatic sorption,
and precipitation. According to Zou et al. (2016b), sorption of Pb(II) by g-C 3 N 4 and
g-C 3 N 4 /β-CD was more efficient in the range of pH 4.0–7.0 than in that of
pH 2.0–4.0. Under extreme pH conditions, the detoxication of heavy metal ions
by nanomaterials decreases significantly, due to the strong electrostatic repulsion
between the adsorbate and the adsorbent (Bhowmick et al. 2014). The dose of
adsorbent is also a key factor influencing the capacity to remove pollutants. Fu
et al. (2015) showed, that together with an increase in the dose of sepiolite-supported
nanoscale zerovalent iron (S-nZVI), the efficiency of removing Cr(VI) rose from
45.1% to 99.2%.
With a view to increasing the stability of solutions of NPs and make them more
effective, nanomaterials can be deliberately improved with different stabilizers,
surfactants, specific chemical substances, or functional groups (Campbell et al.
2015; Guerra et al. 2017). The adjustment of the physical and chemical properties
of nanomaterials, i.e., their size, morphology, porosity, and chemical composition,
may give them additional positive characteristics that may be useful in environmental remediation (Pandey and Fulekar 2012; Tao 2012). nZVI produced by the
borohydride method (surface of 20–40 m
2
∙g
À1 ) shows 10–1000 times higher reactivity than Fe (surface of <1 m
2
∙g
À1 ) (Wang and Zhang 1997). In their studies, Shi
et al. (2011) used nZVI and bentonite-supported nanoscale zerovalent iron (B-nZVI)
to remove pollutants caused by Cr(VI) in solution in water and soil. B-nZVI was
very effective at reducing aggregation and increasing specific surface area compared
to nZVI. Liu et al. (2015) demonstrated that the composite nZVI@Mg(OH) 2 can
remove 94% of Pb(II) within 15 min. The maximum sorption capacity was
1986 mgÁg
À1 . The stabilizer Mg(OH) 2 prevents the aggregation and oxidation of
nZVI particles by high specific surface area and the characteristic pore structure. Li
1 Nanotechnology in Agriculture, the Food Sector, and Remediation: Prospects,. . .
13
recent times, the number of real applications of nZVIs is rapidly growing. PARS
Environmental Inc. estimated the potential costs of remediation of land polluted with
TCE and perchloroethylene (PCE) in a production plant in New Jersey (Karn et al.
2009). Application of the pump and treat method was estimated to cost around
4,160,000 USD, and the permeable reactive barrier (PRB) method at
2,200,000 USD, while the estimated cost of nanotechnology with nZVI was
450,000 USD, a saving of around 80–90% compared to the pump and treat method.
The use of nanotechnology not only reduces operating costs but also reduces the
time for which employees are exposed to the contamination occurring on the site of
the land being reclaimed. Zhang (2003) noted a 99% reduction in the level of TCE
within a few days after use of nZVI.
The sorption of pollutants, mainly heavy metal ions, by nanomaterials depends to
a large extent on environmental conditions (Wu et al. 2019). Lv et al. (2012)
demonstrated that sorption of Cr(VI) by nZVI-Fe 3 O 4 rises to 96.4% within 2 h.
Temperature may have an influence on the rate of removal of pollutants by changing
the energy in the reaction system. Xiong et al. (2014) proved that sorption of Cr
(VI) by the composite γ-Fe 2 O 3 /C@HKUST-1 was more favorable at higher
temperatures. Under neutral pH conditions, nanomaterials are more effective at
removing heavy metal ions, thanks to surface coordination, electrostatic sorption,
and precipitation. According to Zou et al. (2016b), sorption of Pb(II) by g-C 3 N 4 and
g-C 3 N 4 /β-CD was more efficient in the range of pH 4.0–7.0 than in that of
pH 2.0–4.0. Under extreme pH conditions, the detoxication of heavy metal ions
by nanomaterials decreases significantly, due to the strong electrostatic repulsion
between the adsorbate and the adsorbent (Bhowmick et al. 2014). The dose of
adsorbent is also a key factor influencing the capacity to remove pollutants. Fu
et al. (2015) showed, that together with an increase in the dose of sepiolite-supported
nanoscale zerovalent iron (S-nZVI), the efficiency of removing Cr(VI) rose from
45.1% to 99.2%.
With a view to increasing the stability of solutions of NPs and make them more
effective, nanomaterials can be deliberately improved with different stabilizers,
surfactants, specific chemical substances, or functional groups (Campbell et al.
2015; Guerra et al. 2017). The adjustment of the physical and chemical properties
of nanomaterials, i.e., their size, morphology, porosity, and chemical composition,
may give them additional positive characteristics that may be useful in environmental remediation (Pandey and Fulekar 2012; Tao 2012). nZVI produced by the
borohydride method (surface of 20–40 m
2
∙g
À1 ) shows 10–1000 times higher reactivity than Fe (surface of <1 m
2
∙g
À1 ) (Wang and Zhang 1997). In their studies, Shi
et al. (2011) used nZVI and bentonite-supported nanoscale zerovalent iron (B-nZVI)
to remove pollutants caused by Cr(VI) in solution in water and soil. B-nZVI was
very effective at reducing aggregation and increasing specific surface area compared
to nZVI. Liu et al. (2015) demonstrated that the composite nZVI@Mg(OH) 2 can
remove 94% of Pb(II) within 15 min. The maximum sorption capacity was
1986 mgÁg
À1 . The stabilizer Mg(OH) 2 prevents the aggregation and oxidation of
nZVI particles by high specific surface area and the characteristic pore structure. Li
1 Nanotechnology in Agriculture, the Food Sector, and Remediation: Prospects,. . .
13