Overview of Nanoscience in the Environment - Environmental and Human Health Impacts of Nanotechnology - page 8

veterinary medicines, electronics, fuel cells, batteries and additives, paper manufac-
turing and weapons and explosives (PEN, 2005) (Woodrow Wilson data base, http://
www.nanotechproject.org/inventories/consumer/). Commercialization of products
such as self-cleaning glasses, disinfectant tiles and fi lters for air purifi cation dem-
onstrate the early successes of nanosystems for domestic and environmental appli-
cations. Again, this commercialization is at an early stage of rapid growth; for more
detail see Chapter 2 .

1.7 Potential Benefi ts of Nanotechnology

Nanotechnology has large potential benefi ts to a wide rage of disciplines, such as
human health, medicine and the environment. These benefi ts are briefl y discussed
below.

1.7.1 Environmental

Nanomaterials have the potential to improve the environment through the devel-
opment of new solutions to environmental problems, by direct application of nano-
materials to detect, prevent and remove pollutants or by using nanotechnology to
design cleaner industrial process and create environmentally-friendly products.
Nanoparticles can be used to convert pollutants to less harmful chemicals in the
environment using the properties of large surface area, high reactivity and enhanced
transport of nanoparticles. For instance, zero-valent iron nanoparticles have been
used primarily in the United States to remediate ground water contaminated with
chlorinated carbon compounds such as trichloroethylene (Zhang, 2003) and for the
removal of arsenic from anoxic groundwater (Kanel et al. , 2005 ). Other nanoma-
terials such as zero metallophyrinogens have been found to be effective for the
degradation of tetrachlorethylene, trichloroethylene and carbon tetrachloride
under anaerobic conditions (Dror et al. , 2005). Poly(amidoamine) dendrimers can
serve as chelating agents for recovering metal ions such as Cu(II), Ag(I), Fe(III)
and so on from the aqueous phase (Diallo et al. , 2005) and from soils (Xu and Zhao,
2006). Nanoporous ceramic combined with self assembled monolayers of functional
groups have been used to remove heavy metals from wastewater (Mattigod et al. ,
2006). Nanomaterials have also been used for the removal of metal contaminants
from air. For instance, nancomposites of silica and titania have been used for the
removal of elemental mercury vapour as an alternative to conventional activated
carbon injection (Pitoniak et al. , 2005) and nanostructured silica was used to capture
cadmium from an exhaust combustion environment (Lee et al. , 2005 ).
Nanosensors (e.g. zinc oxide (ZnO) semiconductor, tin(IV) oxide (SnO 2) semi-
conductor, etc.,) can also be used to detect chemicals and biological contaminants
in the environment (Vaseashta and Dimova - Malinovska, 2005 ). Semiconductor
nanostructures can play an important role in developing smart materials that can
simultaneously sense and destroy contaminants from the environment (Kamat and
Meisel, 2003). Such a system is extremely useful when it triggers the degradation
operation on demand, that is degradation becomes operational only when the