A112
Paper #2060
ELECTRIFIED NANOFILTERS: THE FUTURE OF CLEAN WATER
Shafa Suddle (sns44@pitt.edu), Daniel Blemler (dcb35@pitt.edu)
Abstract— Although one of the most precious necessities of
life is access to clean drinking water, various countries
throughout the world do not have ready amounts available.
However, many of these locations have access to surface
and groundwater, which, with modern technology, can be
purified and consumed as drinking water. There are several
different techniques that engineers have started to
experiment with in order to obtain clean water—one of
which happens to be the use of nanotechnology in water
treatment.
This paper will investigate and evaluate nanotechnology
in water treatment, specifically, the new methods within
nanofiltration. The engineering and technologies behind
electrified nanofilters will be analyzed and discussed. The
importance of innovation within nanofilters will be assessed,
and the significance of current research and development in
electrified nanofilters will be addressed. Additionally, the
significance of ethical issues involved with nanofiltration
will be considered. The invention of electrified nanofilters is
especially important to civil and environmental engineers
since creating accessible water is something that they strive
to achieve. Clean water is a necessity of life and with
technological advances like this, water will continue to
become more accessible to people all over the world.
Nonetheless, with these innovations, engineers must be
held accountable for their nanofilter products. Abiding by a
strict code of ethics is a must as they lay the frame work for
proper procedures during manufacturing. Holding engineers
to these standards will help to ensure the water produced for
human consumption is pure and therefore safe for use. With
the use of these methods, nanofiltration, and in particular
electrified nanofilters can revolutionize nanotechnology in
water filtration for the future.
TYPES OF NANOTECHNOLOGY
There are many different techniques that engineers have
started to experiment with in order to obtain clean water—
one of which happens to be the use of nanotechnology in
water treatment. Nanotechnology, the engineering of matter
at the nanoscale (1-100 nanometers), has been identified as
a technology that could greatly reduce the problems
associated with water purification and quality.
This
technology is used for the “treatment of surface water,
groundwater, and wastewater contaminated by toxic metal
ions, organic and inorganic solutes, and microorganisms”
[1].
Within nanotechnology, nanoscopic materials such as
carbon nanotubes and alumina fibers are used in the
nanofiltration of water. A team of researchers from D.J.
Sanghvi College of Engineering, in Mumbai, India, stated
that “the main advantages of using nanofilters, as opposed to
conventional systems, are that less pressure is required to
pass water across the filter, they are more efficient, they
have incredibly large surface areas and can be more easily
cleaned by back-flushing compared with conventional
methods” [2]. With these advantages, nanofiltration is worth
the attention of engineers, as it seems to be a possible
answer to the challenge of providing adequate amounts of
inexpensive, clean water for the world’s increasing
population.
Key Words—Efficiency, Electricity, Electrified Nanofilters,
Ethics, Nanowires, Water Filtration
PRESENTING NANOFILTERS
Due to its significance, clean water is something that every
human should have access to. Unfortunately, there are many
places throughout the world that do not have adequate
amounts of clean water or means to purifying water.
Creating new technology within water filtration is extremely
important as it would provide access to quality water for
those with inadequate amounts. Engineers must figure out a
way to distribute clean water in a more cost and time
efficient method and it seems as if the invention of
nanofilters has done exactly that.
Through further development of carbon nanotubes and
alumina fiber filters, nanofiltration could be the leading
method in water purification. If a procedure is developed to
distribute these methods on a large scale, they could help
solve the problem of providing enough clean water for the
world’s population. Furthermore, electrified nanofilters
purify water faster and do it in a more efficient and
inexpensive method by using less electricity and inexpensive
materials such as cloth and silver. Similar to carbon
nanotubes and alumina fiber filters, if this method can be
industrialized, it could be the leading way to efficiently
provide purified water throughout the world.
University of Pittsburgh
Swanson School of Engineering
TYPES OF NANOFILTRATION: CARBON NANOTUBES
Carbon nanotube filters, consisting of “hollow cylinders
with radially aligned carbon nanotube walls,” have been
proven to remove bacterial pathogens from contaminated
water [1]. These nanotubes are produced using thermal
processes which strip carbon atoms from carbon-bearing
materials and then form a hexagonal network of carbon
atoms that are rolled up into a cylinder [3].
March 1, 2012
1
Shafa Suddle
Daniel Blemler
FIGURE 1
Computer simulation of carbon nanotubes [3]
Additionally, these nanotubes are reusable and can be
cleaned; two properties that are vital in cost-effectively
providing clean water. Furthermore, carbon nanotubes have
shown to have an equal or faster flow rate compared to
filters with larger pores which adds to their effectiveness [2].
If these filters are able to be produced for commercial use,
they could be part of the solution in providing adequate,
quality water across the globe.
FIGURE 2
Aluminum Oxide Hydroxide (AlOOH) Fiber [5]
HOW CARBON NANOFILTERS ARE USED FOR TREATING
WATER
These nanofibers, which have been incorporated into
cartridge filters, are capable of absorbing various
contaminants and have extremely high surface areas which
“allow for potential absorption of significant amounts of
contaminants” [5]. Similar to carbon nanotubes, alumina
fiber nanofilters also allow a high flow rate with a low
pressure drop compared to reverse osmosis and
ultrafiltration. With continued research and development,
these filters could also be constructed for widespread use in
water purification.
Researchers believe that carbon nanotubes could provide a
strong advantage over current technologies such as reverse
osmosis and ultrafiltration because water molecules would
be allowed to pass through the filters while contaminants
would not. This filtration process, called size exclusion,
would directly correlate to the increased flow rate and
decreased energy requirement of carbon nanotubes
compared to current water purification techniques. One
manufacturer has a carbon nanotube that, while not at the
full potential researchers believe this method can achieve, is
undoubtedly a step forward in nanofiltration [3]. If this
method is able to reach its predicted full potential, the
previous, less-efficient methods would become obsolete
while quality water would be more accessible to people
around the world.
THE BEST SOLUTION: ELECTRIFIED NANOFILTERS
While the nanofilter technologies previously discussed are
certainly helping to provide access to clean water, a new
innovation seems to be the best solution. A team of
researchers at Stanford University has invented an electrified
nanofilter, which, instead of physically trapping bacteria like
the carbon nanotubes and alumina fibers, pathogens are
allowed to pass through where they are then destroyed by an
electric field. This new method is not only 80,000 times
faster than any other existing filter, but it is also inexpensive,
as it uses very little power to operate [6]. The fact that it is
even cheaper and faster than other filters makes it seem like
the best solution and potentially the future method to
purifying water.
TYPES OF NANOFILTRATION: ALUMINA FIBERS
In addition to carbon nanotubes, alumina fiber filters are a
type of nanofiltration technique that “remove bacteria,
viruses as well as organic and inorganic colloids, much
faster than conventional filters would do” [4]. An Orlandobased company, Argonide Nanomaterial’s, makes a filter
that is able to retain 99.9999+% of viruses at flow rates
several hundred times greater than more porous membranes
[4]. Through continued research and making these particular
filters more obtainable, water purification could moreefficiently be achieved.
THE CREATION OF ELECTRIFIED NANOFILTERS
Discovered by researchers at Stanford University, electrified
nanofilters are created by using a relatively simple method.
To create electrified nanofilters, scientists first take a plain
cotton fabric and dip it into a solution of carbon nanotubes.
They let this fabric dry and then repeat this process, but
instead of dipping it into carbon nanotubes, they dip it into a
silver and nanowire solution. However, these researchers
have also discovered that mixing the carbon nanotubes with
the silver nanowires and then dipping the fabric into this
mixture is just as effective [6]. After mixing the cloth with
the nano-substances, the cotton is let to soak for twenty
HOW ALUMINA FIBER NANOFILTERS ARE USED FOR
TREATING WATER
Alumina nanofibers are very small fibers made from
aluminum metal or aluminum containing materials, ranging
in size from 1-100 nanometers in diameter and several
micrometers in length.
2
Shafa Suddle
Daniel Blemler
water exceeds 105 V/cm, the electricity is able to break down
cell membranes in a process called electroporation [7].
Electroporation is when a cell membrane is subject to an
increase of electrical conductivity by an external source. If
enough electricity is used, the cell can be destroyed.
Secondly, electrified nanofilters are made of silver
nanotubes (Ag NW). Silver is known for killing bacteria;
thus, if any bacteria are able to get past the electricity, the
silver will destroy it. This second filter acts as a back-up to
the first while increasing the effectiveness of the overall
system.
Finally, there is also the possibility that changes in pH
have been able to purify the water. During the filtration
process, the maximum intensity on the surface of the
nanowires is increased to 100 kV/cm. Due to the large
amounts of voltage, the pH on the surface of the wires can
be significantly altered; so much in fact that the pH can drop
to a level as low as 3 [7]. This dramatic change in the pH
may also impact the percent of bacteria inactivated. With the
use of these three filters, electrified nanofilters can purify the
water effectively and efficiently.
minutes until it has dried. Multiple layers of this fabric are
needed to make the filter powerful enough to successfully
purify water, but once the fabrics have become
approximately 2.5 inches thick, they are shaped into a
cylindrical filter and placed into a glass funnel [6]. Water is
then poured into this filter at a rate of 1liter per hour while a
voltage of -+ 20 volts is applied to it. This process must then
be repeated three times in order to produce a filter which
destroys 98% of bacteria [7].
FIGURE 3
This image demonstrates how live cells are pumped into the filter and are
electrified or killed by the Ag NW’s--by the time the bacteria comes out, it
is dead [8].
Nanomaterials are a big advantage in the creation of
nanofilters due to their incredibly small size. Nanomaterials,
such as nanowires, range from 40 to 100 billionths of a
meter which make them easy to stick into cotton [7]. These
materials, due to their strong bonding with the fabric, create
smooth surfaces on the cotton fibers and in turn create a
more conductible surface for the electricity.
The longer nanowires have their own responsibility in
these filters—one of the ends is attached to the nanotubes
while the other end branches off into the space between the
cotton fibers [6]. This branching is useful because it allows
the electricity to go through the fabric which makes the
process much more efficient. Dr. Yi Cui, Professor of
Materials Science and Engineering at Stanford University
and one of the Stanford researchers who helped create this
invention, stated that, “with a continuous structure along the
length, you can move the electrons very efficiently and
really make the filter very conducting” [6]. The more
efficient and conductive this invention is, the more effective
it becomes as a water purification technique.
FIGURE 4
A scanning electron microscope image of silver nanowires and cotton
during the process of constructing the filter. The large fibers are the cotton
[6].
EFFECTIVE AND EFFICIENT
With all new technology, efficiency is an important factor—
if new technology lacks efficiency, than its use in the world
drastically decreases. With this in mind, researchers at
Stanford University have strived to make electrified
nanofilters efficient and they have been successful in several
ways. Traditionally, nanofilters have several problems that
have prevented them from being as efficient as possible. One
of these problems is that in order for nanofilters to purify
water, the pores used to filter the bacteria must be extremely
small. This was not originally considered to be a problem
because the smaller the pores, the more effective the filter
becomes at preventing bacteria from entering the filter.
However, the problem with this method is that having such
small pores severely restricts the filter’s flow rate [6]. It also
THE THREE STEP FILTER PROCESS
There are three different filters that electrified nanofilters
are made with. Firstly, since the electricity applied to the
3
Shafa Suddle
Daniel Blemler
becomes much easier to clog and the filters must therefore
be frequently replaced.
With the discovery of electrified nanofilters, these
problems have been overcome. Firstly, electrified
nanofilters’ method of purification is by flowing water
through the filter and then electrifying it after it has passed
through [6]. Electrified nanofilters are much more efficient
than traditional nanofilters because they do not purify the
water by keeping the bacteria from entering the filter
altogether. Instead, these filters kill the bacteria by
“zapping” it with electricity once inside. The pore size does
not need to be as small or restrictive with this process,
allowing electrified nanofilters to have large pores and a
drastically increased flow rate. Dr. Yi Cui stated that, “our
filter is about 80,000 times faster than filters that trap
bacteria” [6]. By increasing the flow rate, these filters
improve the efficiency of the purification process.
THE ADVANTAGES OF SILVER IN NANOFILTERS
The efficiency of these filters is also demonstrated by how
silver is used in the filtration process. Silver is known for its
antibacterial properties and the inclusion of it in the filter
forms a second filtration method. If, by chance, any of the
bacteria is able to pass through without being electrified, the
silver nanowires will kill it. This “double filtration” avoids
biofouling, “in which bacteria forms a film on a filter.
Biofouling is a common problem in filters that use small
pores to filter out bacteria” [6]. The use of silver helps
decrease the chance of biofouling and in turn reduces the
number of times these filters need to be either replaced or
repaired. The silver nanowires (Ag NW) combined with the
carbon nanotubes also increase the percent of bacteria
filtered out, therefore making these filters more effective.
Figure 5 represents the performance of the electrified
nanofilter running at a flow rate of 1L/h (or 80000L/(h m2)
compared to the same rate for a nanofibrous membrane
operating at 130psi [7].
The efficiency of these devices was tested by placing a
treated solution of water into an agar plate, “a substrate
which includes nutrients and attachment sites for the
bacteria” [7]. These plates were then incubated at 37oC for a
night. Agar plates are very efficient for this type of test due
to how easily they can be read and interpreted. In these
plates, each healthy cell in the solution multiplies and
generates a colony of bacteria after the incubation period.
These colonies can be clearly seen, allowing the healthy
bacteria in the initial solution to be counted and compared to
the amount of healthy bacteria in the solution after the
incubation.
The bacteria tested in this example was Escherichia coli.
It was mixed into a 100 milliliter solution and contained a
density of 107g/mL [7]. It was then put through the
electrified nanofilter five times at five different voltages.
The results show that at 0V, neither the AgNW/carbon
nanotube cotton nor the carbon nanotube cotton alone
filtered the bacteria effectively. However, at -20V the
AgNW/carbon nanotube cotton inactivated 89% of the
bacteria while at +20V it only inactivated 77%. This is a
definite improvement compared to the results of the carbon
nanotube cotton. At -20V it was approximately inactivating
30% of the bacteria and at +20V it decreased even more
until it was barely stopping 10% of the bacteria [7]. These
results show how the use of AgNW increases the efficiency
of these filters and in doing so, helps make them more
affordable.
FIGURE 5
This graph represents how the alterations in voltage and the percent bacteria
inactivated varies between the AgNW/CNT mixture and CNT mixture [7].
Since traditional nanofilters use small pores, water must
be pumped through it at a substantially higher rate than
necessary with electrified nanofilters, therefore using more
electricity. The electrical current used in electrified
nanofilters is 60 mW, which is “barely enough to cause a
tingling sensation in a person…The electrical current can be
generated by a stationary bicycle or by a hand-cranked
device” [8]. In comparison, the power needed by an
ultrafiltration membrane is around 250mW [8]. Due to the
large pores, water does not need to be pumped into the filters
but can instead be pushed through them from the force of
gravity. By using this type of process, the “electricity needed
to run current through the filter was only a fifth of what a
filtration pump would have needed to filter a comparable
amount of water” [6]. By requiring less electricity, these
filters are able to purify water more efficiently and use less
electricity compared to former purification techniques.
4
Shafa Suddle
Daniel Blemler
is a large cost and difficult challenge” [9]. Through utilizing
these filters, water can be made more accessible to the world
at a much lower cost.
THE FUTURE OF CLEAN WATER
Currently, this technology has not been tested enough to be
widely distributed for public use. It has been, however,
tested on E. Coli and shown to destroy 98% of this bacteria.
This filter will need to be tested with various types of
bacteria and produce similar, positive results before it can
truly begin making an impact on the world.
In continuing development, researchers are conducting
experiments with electrified nanofilters by replacing the
cotton with carbon cloth [7]. Carbon cloth is more
conductive and still relatively cheap; while the dimensions
of the cotton used are 2.5mm by 4mm in length, a 20cm by
20cm carbon cloth can be bought at a comparable price [8].
Hopefully, with ongoing tests, these filters will be improved
further and therefore make water more accessible throughout
the world.
FIGURE 6
(B) Agar plate with bacteria solution incubated overnight; the light color is
from a high density of cell colonies, the grey areas are agar without
colonies. (C) Agar plate incubated overnight with paper treated with
AgNWs; no colonies are visible [7].
INEXPENSIVE MATERIALS FOR INEXPENSIVE
TECHNOLOGY
One of the biggest issues with new water purification
technology is whether or not the invention is affordable.
Engineers have learned how to create clean water but
distributing it to impoverished areas in a cost-effective way
still seems to be an immense problem. With this in mind, the
researchers behind electrified nanofilters looked towards
cheap materials that were, “widely available and chemically
and mechanically robust,” such as plain woven cotton [6].
This material is extremely accessible (according to Dr. Yi
Cui’s report, they bought the fabric at Wal-Mart), and it can
be used to conduct electricity [6]. Additionally, the amount
of silver needed to create the filter was “so small the cost
was negligible” [6]. These costs are miniscule compared to
other filters that can range up into thousands of dollars for
material costs.
One of the highest expenses of nanofilters is the cost of
the energy required to pump the water through the filters.
The energy needed in traditional filters is around 190mW
more than in electrified nanofilters [8]. This change in
energy drastically decreased the cost if one considers that
powering a 65mW filter costs much less than powering a
250mW filter. Even though the voltage is less than
traditional filters, electrified nanofilters have been proven to
be 80,000 times faster than traditional filters [6]. The less
time it takes to filter the water, the less amount of money is
required to purify the water. Such energy efficient ways as
found in electrified nanofilters helps to immensely reduce
the cost of water purification.
Also, replacing filters can but just as expensive, if not
more, than operating them. However, since electrified
nanofilters have pores between fibers that range from tens to
hundreds of micrometers, a size that is significantly larger
than that of bacteria, these filters rarely get clogged [7].
According to the American Chemical Society, “such
technology could dramatically lower the cost of a wide array
of filtration technologies for water as well as food, air, and
pharmaceuticals where the need to frequently replace filters
ETHICS IN NANOFILTRATION
Though the nanofiltration methods previously analyzed are
certainly important to providing cheap, quality, adequate
amounts of water to the world’s population, it is perhaps
more important that engineers keep ethical standards in mind
while further developing these innovations. It is not enough
for engineers to simply say that their innovations are
producing clean, pure water. The public sector relies on this
as being true, and if any corners are cut during the
manufacturing process of these nanofilters, the health of the
population would be directly, negatively affected.
While engineers work to restore and improve water
purification techniques, it is imperative that they abide by a
strict code of engineering ethics such as those laid out by the
National Society of Professional Engineers.
More
specifically, when working with a new technological
advancement such as nanofiltration, it is important that the
civil engineers involved in these projects strictly follow
ethics laid out by an institution like the American Society of
Civil Engineers. Through close consideration of these
ethics, engineers participating in this particular improvement
of water purification will be sure they are performing their
jobs to the highest standards.
ETHICAL CODES
Knowledge of the codes of engineering ethics aids engineers
in making ethical and professional decisions concerning the
process of providing clean water. Implementing
nanofiltration to improve and restore the world’s water
supply is a “service provided by engineers [that] requires
honesty, impartiality, fairness, and equity, and must be
dedicated to the protection of the public health, safety, and
welfare” [10]. A professional engineer working in this field
5
Shafa Suddle
Daniel Blemler
“purified” water and noting what effects this bacteria could
have on humans. Any sign of potential concerns should tell
the engineer, operating under strict ethical codes, their
product cannot be released for practical use.
must be attentive to engineering ethics throughout the
project at hand. They must be honest from the beginning—
considering the various options and weighing out what
would be in the customer’s best interest; not their own based
on possible financial gains from using inadequate, less
expensive materials or failing to relentlessly test their
products. Additionally, an engineer who works with water
purification should be devoted to improving public health
and safety by preventing water being accessed by the public
which is not completely safe for consumption.
Nanofiltration also follows the ethical code that
“engineers shall undertake to perform engineering
assignments only when qualified by education or experience
in the technical field of engineering involved” [11]. This
code is particularly important since nanofiltration is a new
innovation to improving water quality.
If someone
experienced in former methods such as reverse osmosis or
ultrafiltration were to undertake a project utilizing electrified
nanofilters, their previous experience may not be enough to
overcome the differences found while working with these
materials. This could lead to faulty manufacturing of the
filters and, consequently, harmful effects on consumers.
A third canon valuable to an ethical engineer is that
“engineers shall build their professional reputation on the
merit of their services and shall not compete unfairly with
others” [11]. Since a nanofiltration project is one that would
often be awarded based upon a bid, it is important that those
competing engineers honestly submit their bids with regards
to previous experience. It would be unethical for an
engineering firm without experience in nanofiltration to
place a “low” bid in an attempt to receive the job without
regard to the merit of their services.
A LONG-LASTING IMPROVEMENT
Improving and utilizing nanofiltration will be essential to
providing clean water to developing countries and places
with inadequate amounts of clean water in the future. As
scientists continue working with these electrified nanofilters,
they will surely find ways to increase their efficiency and
decrease their overall costs. Additionally, further
development should lead to ways of commercially producing
these filters for large-scale use. With this, many places could
have access to an inexpensive method of purifying their
surface and groundwater.
While working under a code of ethics, engineers will be
held accountable for their work which will ensure safe
products that purify water to appropriate levels. Keeping
ethical standards in mind and striving to deliver an
inexpensive, efficient way of purifying water to improve
people’s quality of life, engineers are helping to provide a
crucial part of daily life for years to come.
REFERENCES
[1] M. Botes, T. Cloete, M. Kwaadsteniet and J. Lopez-Romero. (2010).
“Nanotechnology in Water Treatment Applications.” [Online] Available:
http://books.google.com/books?hl=en&lr=&id=_UGytCMXyp8C&oi=fnd&
pg=PA103&dq=nanofiltration+overview&ots=uIrH2clqha&sig=PQLOJb7c
1ZKW78xZy4OjkGEzQ5Q#v=onepage&q=nanofiltration%20overview&f=
false
[2] F. Valli, K. Tijoriwala and A. Mahapatra. (2010, July 28).
“Nanotechnology for Water Purification.” Nuclear Desalination. [Online].
Available: http://www.eurekalert.org/pub_releases/2010-07/ipnfw072810.php
[3] “Carbon Nanotubes in Drinking Water Treatment.” U.S. Army Public
Health Command.[Online]. Available:
http://phc.amedd.army.mil/PHC%20Resource%20Library/Carbonnanotubes
Apr10.pdf
[4] Biliuti, Smaranda. (2010, July 28). “Nanofilters For Pure Water.”
Softpedia. [Online]. Available: http://news.softpedia.com/news/NanofiltersFor-Pure-Water-149548.shtml
[5] “Alumina Nanofiber Filters in Drinking Water Treatment.” U.S. Army
Public Health Command.[Online]. Available:
http://phc.amedd.army.mil/PHC%20Resource%20Library/Alumina%20Nan
ofiber%20filters%20FS%20Feb%202011.pdf
[6] L. Bergeron. (2010, August 31). “High-speed filter uses electrified
nanostructures to purify water at low cost.” Stanford University. [Online].
Available: http://news.stanford.edu/news/2010/august/nano-pure-water083110.html
[7](August 20). “High Speed Water Sterilization Using One-Dimensional
Nanostructures.” Nanoletters. [Online]. Available:
http://pubs.acs.org/doi/full/10.1021/nl101944e
[8] (2010, November). “Nano Focus: Electrified nanostructures enable lowcost water sterilization.” Materials Research Society. [Online].
Available:http://journals.cambridge.org/action/displayAbstract?fromPage=o
nline&aid=7966540
[9] (2010, October 13). “Electrified nano filter promises to cut costs for
clean drinking water.” American Chemical Society. [Online]. Available:
http://portal.acs.org/portal/acs/corg/content?_nfpb=true&_pageLabel=PP_A
RTICLEMAIN&node_id=223&content_id=CNBP_025888&use_sec=true
&sec_url_var=region1&__uuid=3741b6e1-2575-429b-b0f4-527647428808
ETHICS AND THE EFFECT ON CONSUMERS
Although the main goal behind nanofiltration techniques is
to provide clean water to consumers, engineers involved
must constantly be attentive to how much bacteria is actually
blocked by their products. The properties that make
nanofilters fitting for these applications, such as those of
carbon nanotubes, alumina fibers, and electrified filters, may
also have potential health risk concerns. Since these products
are relatively new, limited results are available concerning
the effects they have on consumers. However, there are
“concerns that carbon nanotubes may interfere or damage
DNA [and] could cause harmful effects to organs if
introduced into the body” [3]. Additionally, alumina
nanofibers could be shed from a filter and be ingested or
enter the environment in some other way. In some alumina
fibers, there are “concerns that they may increase the risk of
cardiovascular disease and adversely affect certain types of
brain cells” [5].
With these concerns in mind, it is vital that engineers test
their products to ensure that human health is not affected.
During the manufacturing process, tests should continually
be run, checking the percentage of bacteria released into the
6
Shafa Suddle
Daniel Blemler
[10] (2011) “NSPE Code of Ethics for Engineers.” National Society for
Professional
Engineers.
[Online:
Web
site].
Available:
http://www.nspe.org/Ethics/CodeofEthics/index.html
[11] (2011) “Code of Ethics.” American Society of Civil Engineers. [Online:
Web site]. Available: http://www.asce.org/Leadership-andManagement/Ethics/Code-of-Ethics/
ADDITIONAL RESOURCES
D. Schoen, A. Schoen, L. Hu, H. Kim, S. Heilshorn and Y. Cui. (2010,
August 20). “High Speed Water Sterilization Using One-Dimensional
Nanostructures.”
Nanoletters.
[Online].
Available:
http://pubs.acs.org/doi/full/10.1021/nl101944e
D. Wareham and P. Elefsiniotis. (1996). “Environmental Ethics in
Engineering Education: A Missing Fundamental.” Elsevier Science Ltd.
[Online]. Available:
http://www.iwaponline.com/wst/03412/0197/034120197.pdf
F. Macedonio, E. Drioli, A. Gusev, A. Bardow, R. Semiat and M. Kurihara.
(2012, January 11). “Efficient technologies for worldwide clean water
supply.” Chemical Engineering and Processing: Process Intensification.
[Online]. Available:
http://www.sciencedirect.com/science/article/pii/S0255270111002066
V. Bruggen, M. Manttan and M. Nystrom. (2008, October 22). “Drawbacks
of applying nanofiltration and how to avoid them: A review.” SciVerse.
[Online]. Available:
http://www.sciencedirect.com/science/article/pii/S1383586608002104
ACKNOWLEDGMENTS
We would like to thank the writing instructors and librarians
for their advice during class time and our professors for
allowing them to come in. Additionally, we appreciate the
help our co-chair and writing instructor have given us.
7