6.7.1 Goethite (a-FeOOH)
Goethite is natural occurring mineral and acts as a good adsorbent hence used in the
removal of vast varieties of pollutants. Goethite has exceptional qualities, high
adsorption efficiency, biocompatible and are cost effective (Massalimov et al.
2014). They are widely prepared by hydrothermal synthesis, sol gel, and precipitation techniques (Sugimoto et al. 1993). They are known for the removal of substantial amount of uranium than any other nanomaterial. In case of Cd high energy ball
milling method is employed for the removal process (Khezami et al. 2016).
6.7.2 Hematite (a-Fe 2 O 3 )
Hematite considered to be one of the most stable oxides of the iron (Tadic et al.
2014) used as a versatile adsorptive nanomaterial for the heavy metal remediation.
Hematite is also used for the removal of lithium from ion batteries (Chen et al. 2012;
Guo and Barnard 2013). Nano-hematite of different morphological structures like
nano cubes, flat plate, cubical, spherical, and rounded was synthesized for the
adsorption of Cr. In hematite nanomaterials morphology and structural orientation
play a very decisive role in the removal of contaminants (Adegoke et al. 2014).
Studies show that these nanoparticles are used for the removal of large strata of
heavy metals like aluminum, zinc, nickel, and magnesium from acid mine drainage.
It is considered to be promising adsorbent because of high stability, non-toxic nature,
and superlative adsorption capability.
6.7.3 Magnetite (Fe 3 O 4 )
The magnetite nanoparticles are used for the removal of contaminants from wastewater as they are easily separable by applying the external magnetic field. They are
synthesized by precipitation, micro-emulsion, and thermolysis of precursor. They
are cost effective, stable, easily available, and eco-friendly nature make them
promising adsorbent for the eradication of different heavy metals. They are
stabilized by the coating of inorganic materials and also provide sites for ligands
to bind covalently. From the literature study there are absolute reports of its
application in the heavy metal removal like Mn, Pb, Zn depicted below in Fig. 6.6
(Watts et al. 2015; Giraldo et al. 2013; Shan et al. 2015; Mahmoud et al. 2016a).
6.8
Nanocomposites
These are the class of material in which one more phase with nanodimensions is
embedded in a metal, ceramic, and polymer matrix. It is hybrid material which has
many advantages over different material (Lu et al. 2016).
6 Nanotechnology for the Remediation of Heavy Metals
155
Goethite is natural occurring mineral and acts as a good adsorbent hence used in the
removal of vast varieties of pollutants. Goethite has exceptional qualities, high
adsorption efficiency, biocompatible and are cost effective (Massalimov et al.
2014). They are widely prepared by hydrothermal synthesis, sol gel, and precipitation techniques (Sugimoto et al. 1993). They are known for the removal of substantial amount of uranium than any other nanomaterial. In case of Cd high energy ball
milling method is employed for the removal process (Khezami et al. 2016).
6.7.2 Hematite (a-Fe 2 O 3 )
Hematite considered to be one of the most stable oxides of the iron (Tadic et al.
2014) used as a versatile adsorptive nanomaterial for the heavy metal remediation.
Hematite is also used for the removal of lithium from ion batteries (Chen et al. 2012;
Guo and Barnard 2013). Nano-hematite of different morphological structures like
nano cubes, flat plate, cubical, spherical, and rounded was synthesized for the
adsorption of Cr. In hematite nanomaterials morphology and structural orientation
play a very decisive role in the removal of contaminants (Adegoke et al. 2014).
Studies show that these nanoparticles are used for the removal of large strata of
heavy metals like aluminum, zinc, nickel, and magnesium from acid mine drainage.
It is considered to be promising adsorbent because of high stability, non-toxic nature,
and superlative adsorption capability.
6.7.3 Magnetite (Fe 3 O 4 )
The magnetite nanoparticles are used for the removal of contaminants from wastewater as they are easily separable by applying the external magnetic field. They are
synthesized by precipitation, micro-emulsion, and thermolysis of precursor. They
are cost effective, stable, easily available, and eco-friendly nature make them
promising adsorbent for the eradication of different heavy metals. They are
stabilized by the coating of inorganic materials and also provide sites for ligands
to bind covalently. From the literature study there are absolute reports of its
application in the heavy metal removal like Mn, Pb, Zn depicted below in Fig. 6.6
(Watts et al. 2015; Giraldo et al. 2013; Shan et al. 2015; Mahmoud et al. 2016a).
6.8
Nanocomposites
These are the class of material in which one more phase with nanodimensions is
embedded in a metal, ceramic, and polymer matrix. It is hybrid material which has
many advantages over different material (Lu et al. 2016).
6 Nanotechnology for the Remediation of Heavy Metals
155