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• Carbon-Based Nanoadsorbents
Carbon-based nanomaterials (inorganic materials) are mostly used for removal
of heavy metals because they are nonpoisonous and innocuous. These materials also
have high adsorption capacities (Zhang et al. 2009). It is also not easy to eliminate
heavy metals at lower level (ppb). With the progress of nanotechnology, fullerene,
graphene, and carbon nanotubes are prepared and applied as nanoadsorbents (carbon nanotubes) that are widely used for adsorption purposes because of their unique
properties (structural, semiconductor, and mechanical, chemical, and physical)
which play vital role in the adsorption of toxicants. Carbon nanotubes are applied as
nanoadsorbents separately or modified using other materials (metal ions or metal
oxides, organic compounds) in order to increase their sorption capacities.
• Nanoadsorbents from Metal and Metal Oxides
Nanocomposites prepared from metal or metal oxides (such as silver (Ag) metal
nanoparticles, ferric oxides (FeO), titanium oxides (TiO), magnesium oxides
(MgO), and copper oxides (CuO)) are also widely used for the elimination of aqueous phase toxicants and treatment of industrial effluents. As these metal ions possess high surface area and particular attraction, these metal oxides exhibit efficient
adsorption capacity, but their separation from the wastewater is not easy because of
their high surface energy and nano-size (Wang et al. 2012).
• Polymer Clay Supported Nanoadsorbents
An efficient sorbent should possess specific functionalities and must have high
surface area. Inorganic sorbents showed large surface area but deprived of adsorbing functionalities. Organic polymeric materials contain large amount of functional
groups (−NH 2 ), and –OH group) could efficiently adsorb heavy metal ions but their
small surface area and less adsorption capacity restrict their uses. To vanquish and
control this imperfection, newly encouraging organic–inorganic hybrid materials
have been applied to eliminate pollutants from environmental compartments
(Samiey et al. 2014). Therefore, new sorbents that not only contain polyfunctional
groups but also have high surface area have been synthesized. In such composite,
the functional organic substance is coupled to the benefits of a heat-resistant, tough,
and long-lasting inorganic material causing well-built bonding harmony for desired
pollutant ions. Modified organic–inorganic compounds as sorbent are known as the
best efficient approach because of toxicant ions that form complex with them. Such
types of products offer combination of beneficial characteristics (physical, chemical, and mechanical properties).
The formation of these hybrid adsorbents has open new doors for deep elimination of pollutants from aqueous media. Polymer clay nanocomposites are used as
nanoadsorbents in which clay provide surface area and polymer moiety provide
functional groups so hybrid materials with desired application have been prepared
and used for the adsorption of toxic metals such as Cu
2+
, Pb
2+
, etc. (Liu et al. 2010).
Variety of polymer/organoclay composite have been reported in literature such as
clay/polystyrene (Okamoto et al. 2000), and poly(methyl methacrylate)/clay
A. Sabir et al.
• Carbon-Based Nanoadsorbents
Carbon-based nanomaterials (inorganic materials) are mostly used for removal
of heavy metals because they are nonpoisonous and innocuous. These materials also
have high adsorption capacities (Zhang et al. 2009). It is also not easy to eliminate
heavy metals at lower level (ppb). With the progress of nanotechnology, fullerene,
graphene, and carbon nanotubes are prepared and applied as nanoadsorbents (carbon nanotubes) that are widely used for adsorption purposes because of their unique
properties (structural, semiconductor, and mechanical, chemical, and physical)
which play vital role in the adsorption of toxicants. Carbon nanotubes are applied as
nanoadsorbents separately or modified using other materials (metal ions or metal
oxides, organic compounds) in order to increase their sorption capacities.
• Nanoadsorbents from Metal and Metal Oxides
Nanocomposites prepared from metal or metal oxides (such as silver (Ag) metal
nanoparticles, ferric oxides (FeO), titanium oxides (TiO), magnesium oxides
(MgO), and copper oxides (CuO)) are also widely used for the elimination of aqueous phase toxicants and treatment of industrial effluents. As these metal ions possess high surface area and particular attraction, these metal oxides exhibit efficient
adsorption capacity, but their separation from the wastewater is not easy because of
their high surface energy and nano-size (Wang et al. 2012).
• Polymer Clay Supported Nanoadsorbents
An efficient sorbent should possess specific functionalities and must have high
surface area. Inorganic sorbents showed large surface area but deprived of adsorbing functionalities. Organic polymeric materials contain large amount of functional
groups (−NH 2 ), and –OH group) could efficiently adsorb heavy metal ions but their
small surface area and less adsorption capacity restrict their uses. To vanquish and
control this imperfection, newly encouraging organic–inorganic hybrid materials
have been applied to eliminate pollutants from environmental compartments
(Samiey et al. 2014). Therefore, new sorbents that not only contain polyfunctional
groups but also have high surface area have been synthesized. In such composite,
the functional organic substance is coupled to the benefits of a heat-resistant, tough,
and long-lasting inorganic material causing well-built bonding harmony for desired
pollutant ions. Modified organic–inorganic compounds as sorbent are known as the
best efficient approach because of toxicant ions that form complex with them. Such
types of products offer combination of beneficial characteristics (physical, chemical, and mechanical properties).
The formation of these hybrid adsorbents has open new doors for deep elimination of pollutants from aqueous media. Polymer clay nanocomposites are used as
nanoadsorbents in which clay provide surface area and polymer moiety provide
functional groups so hybrid materials with desired application have been prepared
and used for the adsorption of toxic metals such as Cu
2+
, Pb
2+
, etc. (Liu et al. 2010).
Variety of polymer/organoclay composite have been reported in literature such as
clay/polystyrene (Okamoto et al. 2000), and poly(methyl methacrylate)/clay
A. Sabir et al.