Environmental Engineering Reference
In-Depth Information
provides solutions to environmental problems
:
This involves application of existing princi-
ples of green chemistry and green engineering
to produce nanomaterials without employing
toxic ingredients, at comparatively low tem-
peratures and using less energy and renewable
inputs wherever and whenever possible and
utilizing life cycle thoughts in all stages of
design and engineering. In addition, this fi eld
also means using nanotechnology to make
current manufacturing processes for non-
nanomaterials and more eco-friendly prod-
ucts. For instance, nanoscale membranes can
separate desired chemical reaction products
from waste materials. More effi cient and less
wasteful chemical reactions are possible by
employment of nanoscale catalysts. Nanoscale
sensors can form part of process control sys-
tems, working with nano-enabled information
systems. Using alternative systems via nano-
technology is another way to “green” manu-
facturing processes.
2 .
Development of products that benefi t the
environment either directly or indirectly
:
Nanomaterials have been found capable of
directly cleaning hazardous waste sites, desali-
nate water and treat pollutants. Indirectly,
lightweight nanocomposites for automobiles
and other means of transport have been able to
save fuel and reduce materials used for pro-
duction. Nanotechnology-enabled fuel cells
and LEDs are capable of reducing energy from
energy generation and aid in fossil fuel conser-
vation. Self-cleaning nanoscale surfaces have
the ability to reduce or eliminate many clean-
ing chemicals used in regular maintenance
routines (Sustainable Nano Coatings
2013
).
Green nanotechnology has a wider view of
nanomaterials and nanoproducts, ensuring
minimization of unforeseen consequences and
anticipation of the impacts throughout the life
cycle (Klöppfer et al.
2007
).
and self-cleaning properties combine to create
more effi cient solar panels. PV panels covered
with nanotechnology coatings have found to
stay cleaner for longer duration thus ensuring
maintenance of maximum energy effi ciency
(nanoShell
2013
).
3
Green Chemistry
Green chemistry, also called sustainable chemis-
try, is a philosophy of chemical research and
engineering that encourages the design of prod-
ucts and processes that minimize the use and
generation of hazardous substances. It differs
from environmental chemistry in the fact that
environmental chemistry deals with chemistry of
the natural environment and of pollutant chemi-
cals in nature. Whereas in green chemistry it
seeks answers to questions regarding reduction
and prevention of pollution at its source, which
in turn applies to organic chemistry, inorganic
chemistry, biochemistry, analytical chemistry,
and physical chemistry (USEPA
2006
). Three
key developments have been identifi ed in green
chemistry (Noyori
2005
):
1. Use of supercritical CO
2
as green solvent
2. Use of aqueous H
2
O
2
for clean oxidations
3. Use of hydrogen in asymmetric synthesis
3.1
Principles of Green Chemistry
Green chemistry has 12 principles that explain
what the defi nition means practically and covers
the following concepts (Anastas and Warner
1998
):
1. Design of processes to maximize the amount
of raw materials that ends up as products.
2. Use of safe, environment-benign substances
whenever possible.
3. Design of energy-effi cient processes.
4. The best form of waste disposal: avoid creat-
ing it in the fi rst place.
The 12 principles are as follows:
1 .
Prevention
: Better to prevent waste than to
treat or clean up waste after it has been
created.
Current research involves the development of
nanotechnology in solar cells which are a renew-
able resource (Gail
2009
). The potentials of this
fi eld are already in application for provision of
improved performance coatings for photovol-
taic (PV) and solar thermal panels. Hydrophobic
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