(Isogai et al. 2011). For treating pollution laden environment, nanostructures could
be metal driven or metal free.
Metal-Free Nanostructures Nanostructures without the involvement of metals do
possess inimitable two-dimensional properties such as mechanical, optical, physical
and chemical as well, which made them material of choice for treating pollution.
Production of stable BN nanosheets with the doping of carbon have higher potential
of electron-hole pairs generation with the stimulation of visible light (Huang et al.
2015).
Metal-Nanostructures High surface to volume ratio synchronized with shorter
diffusion distances of nano-photocatalysts augments their enactment manifolds (Ren
et al. 2017). Sun et al. had reported synthesis of photo catalytically efficient
nanotubes of monoclinic BiVO 4 with 60 times enhanced surface area than its bulk
counterparts (Sun et al. 2010). The enhanced activity is attributable to lower
electron-hole recombination rates along with generation of radical and active sites
on surface of nanotubes for adsorption of pollutants. It has been reported that
CdS-loaded TiO 2 nanotubes take visible spectrum of light to trigger the
photocatalytic activity (Banerjee et al. 2008). Coupling of g-C 3 N 4 with different
semiconductors such as SnO 2 (Yin et al. 2014) , CeO 2 (Huang et al. 2013), and ZnO
(Sun et al. 2012) has been successfully carried out. The resultant coupling offers
better results in the form of more efficient photocatalyst because of effective band
gap convergence and enhanced resistance to photocorrosion.
Day-by-day increasing concerns of pollution has deviated most of the attention of
research world towards the treatment and abatement of pollution. This concerned
threat is tackled on two fronts: firstly by preventing the pollution and secondly by
treating the already polluted spheres. Most of the undiscovered portion of hydrosphere still comes in contact to the human interference in the form of pollution.
Run-off from land areas along with the intentional discharge from industrial plants
has a serious considerable share in polluting the surface water bodies. In addition to
this, human mobility and export-import conducted via waterways aggravates the
situation with the accidental instances of oil-spillage resulting in arousal of life
threatening concerns for aquatic micro as well as macro flora.
3.4.1 Nanotechnology in Hydrosphere
Hydrosphere covering around 71% of geographical area of earth is the abode of
more than billions of creatures. For meeting global water crisis, nanoscience is
emerging as a best possible tool with the fabrication of separation membranes of
high efficiency and enhanced performance. Different categories of nanomaterials
(such as nanospheres, nanofiber, nanocomposites, nanorods) with anti-pathogenic
and antifouling properties, symbiotic with enhanced permeation properties paved
their way for being designed as pollutant specific and briskly active water purifying
membranes (Ying et al. 2017). One of the recent advancements in nanofield is
attainment of membrane synthesis in the form of nanofiber membranes with high
aspect ratio (Wang and Hsiao 2016), 2-D layered self-assembled membranes (Ying
3 Environmental Nanotechnology: Its Applications, Effects and Management
51
be metal driven or metal free.
Metal-Free Nanostructures Nanostructures without the involvement of metals do
possess inimitable two-dimensional properties such as mechanical, optical, physical
and chemical as well, which made them material of choice for treating pollution.
Production of stable BN nanosheets with the doping of carbon have higher potential
of electron-hole pairs generation with the stimulation of visible light (Huang et al.
2015).
Metal-Nanostructures High surface to volume ratio synchronized with shorter
diffusion distances of nano-photocatalysts augments their enactment manifolds (Ren
et al. 2017). Sun et al. had reported synthesis of photo catalytically efficient
nanotubes of monoclinic BiVO 4 with 60 times enhanced surface area than its bulk
counterparts (Sun et al. 2010). The enhanced activity is attributable to lower
electron-hole recombination rates along with generation of radical and active sites
on surface of nanotubes for adsorption of pollutants. It has been reported that
CdS-loaded TiO 2 nanotubes take visible spectrum of light to trigger the
photocatalytic activity (Banerjee et al. 2008). Coupling of g-C 3 N 4 with different
semiconductors such as SnO 2 (Yin et al. 2014) , CeO 2 (Huang et al. 2013), and ZnO
(Sun et al. 2012) has been successfully carried out. The resultant coupling offers
better results in the form of more efficient photocatalyst because of effective band
gap convergence and enhanced resistance to photocorrosion.
Day-by-day increasing concerns of pollution has deviated most of the attention of
research world towards the treatment and abatement of pollution. This concerned
threat is tackled on two fronts: firstly by preventing the pollution and secondly by
treating the already polluted spheres. Most of the undiscovered portion of hydrosphere still comes in contact to the human interference in the form of pollution.
Run-off from land areas along with the intentional discharge from industrial plants
has a serious considerable share in polluting the surface water bodies. In addition to
this, human mobility and export-import conducted via waterways aggravates the
situation with the accidental instances of oil-spillage resulting in arousal of life
threatening concerns for aquatic micro as well as macro flora.
3.4.1 Nanotechnology in Hydrosphere
Hydrosphere covering around 71% of geographical area of earth is the abode of
more than billions of creatures. For meeting global water crisis, nanoscience is
emerging as a best possible tool with the fabrication of separation membranes of
high efficiency and enhanced performance. Different categories of nanomaterials
(such as nanospheres, nanofiber, nanocomposites, nanorods) with anti-pathogenic
and antifouling properties, symbiotic with enhanced permeation properties paved
their way for being designed as pollutant specific and briskly active water purifying
membranes (Ying et al. 2017). One of the recent advancements in nanofield is
attainment of membrane synthesis in the form of nanofiber membranes with high
aspect ratio (Wang and Hsiao 2016), 2-D layered self-assembled membranes (Ying
3 Environmental Nanotechnology: Its Applications, Effects and Management
51