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21 Nanomaterials and Biopolymers for the Remediation of Polluted Sites

Trujillo and Reyes [34] described the efficiency of nZVI for the remediation of

aqueous solutions contaminated with ibuprofen in soils. Likewise, Olson et al.

[35] conducted studies on polluted soil with bivalent metal nanoparticle (Fe

and Mg) in order to reduce the concentration of PCBs in soils. Lot of efforts are

being made to make use of nano-N fertilizers for controlling the loss of nutri-

ents. A high-performance nanoformulation was developed using clay–sodium

polyacrylate–polyacramide for binding nitrogenous fertilizer [36].

Engineered nanomaterials used in soil remediation are nanoscale calcium

peroxide, nanoscale zero-valent iron, nanoscale metal oxides, and other nanopar-

ticles, such as carbon nanotubes, bionanoparticles, polymeric nanoparticles, etc.

They are mainly used in the removal of aromatic and heavy metal contaminants.

However, in-depth study regarding the impact of these engineered nanomaterials

on the surrounding environment and their mobility is very much necessary.

Calcium peroxide nanoparticles have recently been applied to remediate soil

contaminated with oil the most widely exploited nanoremediation technique is

the application of nZVI in groundwater and soil remediation [37]. Other classes of

nanomaterial which are being used in the process of soil remediation are carbon

nanoparticles, polymeric nanoparticles (nanowire of polypyrrole, polyaniline, and

poly(3,4-ethylenedioxythiophene),

dendrimers

poly(amidoamine)

[PAMAM]),

nanocomposites, and bionanoparticles (virus, plasmids, proteins, etc.) [38]. Allo-

phane is a nanoscale hydrous aluminosilicate and an effective sorbent of copper.

Yuan have demonstrated the removal of Cu from soil using a natural nanomaterial

as an adsorbent material, allophane under laboratory scale [39].

Nanoparticles are seen to be the potential entities for the remediation of soil.

Nanoparticles are much more efficient and highly selective for the removal of

heavy metal contaminants. Iron-based nanoparticles are being widely used for the

heavy metal removal from soil as they possess very strong adsorption property

and excellent reducing property. The small size of the nanomaterials increases

their mobility and deliverability in soil, and thus the heavy metals are stabilized or

converted to less toxic species in soil. Nanotechnology has become a reliable means

to remediate heavy-metal-contaminated soil. Most of the studies are conducted

in laboratory scale, and therefore, much effort should be made to improvise in

bringing it to the field scale.

Nanotechnology as an upcoming technology has shown great potential in var-

ious fields such as solar, electronics, optics, and pharmaceuticals. Nanomaterial-

mediated environmental remediation offers great alternative in cleaning up of

large-scale contaminated sites at low cost. Several metal/metal oxides and biopoly-

meric materials can be successfully employed for a variety of environmental

remediation. Selection of appropriate nanomaterial for the mitigation of polluted

area requires in-depth knowledge. Although several publications and patents have

been reported pertaining to the application of nanomaterials/nanobiopolymeric

composites developed via green route for the removal of contaminants from nature;

deeper understanding along with extensive research regarding the ecological effect

of the same is very much essential.