Green Nanotechnology: The Solution to Sustainable Development of Environment - Environmental Sustainability: Role of Green Technologies - page 299

2 . Atom economy : Designing of synthetic
methods to maximize the incorporation of
all materials used in the process into the
fi nal product.
3 . Less hazardous chemical syntheses :
Designing of synthetic methods, wherever
practicable, to use and generate substances
that possess little or no toxicity to human
health and the environment.
4 . Designing safer chemicals : Designing of
chemical products to affect their desired
function while minimizing their toxicity.
5 . Safer solvents and auxiliaries : Use of auxil-
iary substances (e.g., solvents, separation
agents, etc.) should be made unnecessary
wherever possible and innocuous when used.
6 . Design for energy effi ciency : Energy require-
ments of chemical processes should be
recognized for their environmental and eco-
nomic impacts and should be minimized. If
possible, synthetic methods should be con-
ducted at ambient temperature and pressure.
7 . Use of renewable feedstocks : A raw material
or feedstock should be renewable rather than
depleting whenever technically and econom-
ically practicable.
8 . Reduce derivatives : Unnecessary derivatiza-
tion (use of blocking groups, protection/
deprotection, temporary modifi cation of
physical/chemical processes) should be min-
imized or avoided if possible because such
steps require additional reagents and can
generate waste.
9 . Catalysis : Catalytic reagents (as selective as
possible) are superior to stoichiometric
reagents.
10. Design for degradation : Chemical products
should be designed so that at the end of their
function, they break down into innocuous
degradation products and do not persist in
the environment.
11. Real-time analysis for pollution prevention :
Analytical methodologies need to be further
developed to allow for real-time, in-process
monitoring and control prior to the forma-
tion of hazardous substances.
12. Inherently safer chemistry for accident pre-
vention : Substances and the form of a sub-

stance used in a chemical process should be
chosen to minimize the potential for chemi-
cal accidents including releases, explosions,
and fi res.
Green chemistry is being increasingly used as
a powerful tool for evaluation of environmental
impact of nanotechnology by researchers
(Schmidt 2007 ).

4 Green Engineering

Green engineering is the process and design of
products that conserve natural resources and
impact the natural environment as little as possi-
ble. The term is mostly used in connection to
housing, but is also applicable to automobiles,
lights, or anything that requires engineering, with
incorporation of environmental principles. Green
engineers are specially trained in the fi eld with
regard to making of materials in an environmen-
tally friendly way. For example, in case of hous-
ing, they are concerned with the latest building
materials and techniques, which may include the
use of solar-powered devices like water heaters,
solar lights or windows, and other design ele-
ments. Concepts used in automobiles that are con-
sidered environmentally friendly include hybrid
technologies such as fl ex-fuel vehicles and elec-
tricity. The consumption of less energy could
mean a chance to realize cost savings in the opera-
tions of these vehicles over time (Ken 2013 ).

4.1 Principles of Green

Engineering

Green engineering has the following 12 princi-
ples (Anastas and Zimmerman 2003 ):
1 . Inherent rather than circumstantial :
Designers need to strive to ensure that all
materials and energy inputs and outputs are
as inherently nonhazardous as possible.
2 . Prevention instead of treatment : Better to
prevent waste than to treat after formation.
3 . Design for separation : Designing of separa-
tion and purifi cation operations to minimize
energy consumption and material use.