Session A4
Paper 6165
Disclaimer — This paper partially fulfills a writing requirement for first year (freshman) engineering students at the
University of Pittsburgh Swanson School of Engineering. This paper is a student, not a professional, paper. This paper is
based on publicly available information and may not be provide complete analyses of all relevant data. If this paper is used
for any purpose other than these authors’ partial fulfillment of a writing requirement for first year (freshman) engineering
students at the University of Pittsburgh Swanson School of Engineering, the user does so at his or her own risk.
TiO2 AND GRAPHENE PHOTOCATALYSTS FOR WATER PURIFICATION
Tristan Abraham, tma37@pitt.edu, Mahboobin 10:00, Christina Rogers, clr76@pitt.edu, Vidic 2:00
Revised Proposal — With the inevitable effects of climate
change, societies face the challenge of providing more water
to an increasing population with reduced water supplies.
Though the practice of filtering water dates back thousands
of years, many methods still lack the ability to purify water
to a degree necessary for modern society. Even water
purification methods that can purify water to that degree are
too costly and energy-intensive to be economical. However,
a newly developed titanium oxide and graphene filtering
process makes the elusive goal of finding an inexpensive,
efficient and effective way to provide clean water on a large
scale a reality. This scientific development has the ability to
significantly increase the accessibility to clean water around
the world.
To begin this process, titanium dioxide, TiO2, is modified
into an ideal shape and paired with graphene. This pairing
and modification process allows it to absorb the UV-rays in
sunlight in such a way to start the reactions [1]. This step is
entirely driven by the power of the sun rather than large
amounts of electricity or fossil fuels which are used in other
purification processes. The reactions involved in the process
feature reduction of graphene surface groups, which creates
a product called rGO, a form of graphene oxide [2]. The
process removes organic compounds, pesticides, and many
other harmful pollutants. Although the process does not take
care of the initial steps in water purification, it purifies
water further so that it is disease free and safe for
consumption, and it matches the standards set by the
Environmental Protection Agency for clean water [1] [3].
These qualities make the TiO2 filtration process a viable
candidate to provide many with access to clean and
drinkable water [1].
Although this process provides a giant leap in securing the
water demands of future generations around the world, it is
just an evolution of existing technology. The use of TiO 2 has
been around for quite some time, but in previous
applications it was very expensive and extremely inefficient
due to the power requirements which were typically fulfilled
using fossil fuels. However, this new and innovative process
uses the power of the sun in order to meet the initial
reactions activation energy. Although there are other
processes that can be utilized for water purification such as
desalination, or distillation, they are too inefficient, costly,
or produce harmful byproducts. This makes TiO2 an ideal
University of Pittsburgh Swanson School of Engineering 1
2016/01/29
solution to address the water challenges the world faces
today.
Water scarcity is considered a large global threat of our
time by many world governments [4]. One tenth of the
world’s population lacks clean drinking water, which
equates to more than twice the population of the United
States. Lack of water security poses a threat to the world
economy because it will decrease industrial output which
requires high amounts of water as well as pose a danger to
those individuals without access to water [5]. Engineers
have developed TiO2 filtration technology that can solve
many of these problems if adequate funding, support, and
planning are applied to its development.
This paper will research the benefits of using TiO2 and
graphene in purification systems and analyze the cost,
efficiency, and benefits of the technology. This paper will
also carefully consider how these systems would be
implemented widely across water scarce regions and thus
present solutions to the great challenges posed by water
shortages.
REFERENCES
[1] Bernstein, Michael. (2014). “High tech materials purify
water with sunlight.” American Chemical Society. (Online
article).
http://www.acs.org/content/acs/en/pressroom/newsreleases/2
014/march/high-tech-materials-purify-water-withsunlight.html
[2] Morales-Torres, S and Pastrana-Martinez, L. M. (2014).
“Nanostructured carbon–TiO2 photocatalysts for water
purification: an overview.” Bol Grupo Espanol Carbon.
(PDF).
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&sourc
e=web&cd=1&cad=rja&uact=8&ved=0ahUKEwi9yvmS0af
KAhVJeT4KHdbkAgQFggiMAA&url=http%3A%2F%2Fdialnet.unirioja.es%2F
descarga%2Farticulo%2F5076831.pdf&usg=AFQjCNHRxO
cAIrK6Yu6TSNuYV7Syxx0NrA&sig2=Mbo9wN_YREQC
Ml77MESK5w
[3] Dougherty, Cynthia. (2015). “Tap Into It.”
Environmental Protection Agency. (PDF).
http://nepis.epa.gov/Exe/ZyNET.exe/200024QJ.txt?ZyActio
nD=ZyDocument&Client=EPA&Index=1995%20Thru%201
999&Docs=&Query=&Time=&EndTime=&SearchMethod=
Tristan Abraham
Christina Rogers
experimental data to support the paper’s presentation of
TiO2 and graphene as an effective filter pair.
1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYea
r=&QFieldMonth=&QFieldDay=&UseQField=&IntQField
Op=0&ExtQFieldOp=0&XmlQuery=&File=D%3A%5CZY
FILES%5CINDEX%20DATA%5C95THRU99%5CTXT%5
C00000015%5C200024QJ.txt&User=ANONYMOUS&Pass
word=anonymous&SortMethod=h%7C&MaximumDocuments=1&FuzzyDegree=0&ImageQuality
=r75g8/r75g8/x150y150g16/i425&Display=p%7Cf&DefSee
kPage=x&SearchBack=ZyActionL&Back=ZyActionS&Bac
kDesc=Results%20page&MaximumPages=1&ZyEntry=2
[4] (2015). “Global Water Crisis: Water and Sanitation
Facts.” water.org. (Online article). http://water.org/watercrisis/water-sanitation-facts/
[5] “Evaluation of the Costs and Benefits of Water and
Sanitation Improvements at the Global Level.” (2015). The
World
Health
Organization.
(Online
Article).
http://www.who.int/water_sanitation_health/wsh0404summa
ry/en/
J.Liu, H. Bai, Y. Wang, Z. Liu, X. Zhang, D.Sun. (2010).
Self-Assembling TiO2 Nanorods on Large Graphene Oxide
Sheets at a Two-Phase Interface and Their AntiRecombination in Photocatalytic Applications. (Online
Article).
http://onlinelibrary.wiley.com/doi/10.1002/adfm.201001391/
full.
This paper was published by the scientific journal
Advanced Functional Materials. The paper shows the
usefulness of the TiO2 and graphene technology in the
degradation of methylene blue, a notoriously difficult to
filter toxin. This paper will be used to describe the process
by which the pair degrades this specific pollutant along with
why this is important to water purification.
“Global Water Crisis: Water and Sanitation Facts.” (2015).
Water.org.
(Online
Article).
http://water.org/watercrisis/water-sanitation-facts/
This website, published by an international organization
working to provide clean water to impoverished people,
provides facts about water distribution, poverty and the need
for access to water across the globe. This will be used to
present the challenges society faces due to the lack of clean
water, what this causes on a grander scale, and why an
innovative solution to this problem is necessary.
ANNOTATED BIBLIOGRAPHY
S. Morales-Torres, L. M. Pastrana-Martinez.(2014).
“Nanostructured Carbon–TiO2 Photocatalysts for Water
Purification: An Overview.” Bol Grupo Espanol Carbon.
(Academic
Journal).
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&sourc
e=web&cd=1&cad=rja&uact=8&ved=0ahUKEwi9yvmS0af
KAhVJeT4KHdbkAgQFggiMAA&url=http%3A%2F%2Fdialnet.unirioja.es%2F
descarga%2Farticulo%2F5076831.pdf&usg=AFQjCNHRxO
cAIrK6Yu6TSNuYV7Syxx0NrA&sig2=Mbo9wN_YREQC
Ml77MESK5w
This paper, written by the Laboratory of Catalysis and
Materials and found through Academic Search Premier,
discusses the fundamentals of photocatalysts and their use
for degrading organic pollutants. In particular, this paper
outlines the process that the TiO2, graphene and UV rays
undergo and describes the complexities of the reaction. This
article will be used to present how the chemical processes
involved in graphene filtering work as well as the net benefit
of those chemical processes.
“TiO2: A New Kind of Water Treatment.” (2014). Royal
Society
of
Chemistry.
(Online
Article).
http://www.rsc.org/learnchemistry/resource/download/res00001265/cmp00002615/p
df
This paper, published by The Wolfson Foundation,
outlines the benefits as well as the potential drawbacks of
solar disinfection using TiO2. This includes an analysis of
why the technology works and details of the process
including the involvement of semiconductors. This source
will be useful in identifying what some of the drawbacks of
this technology will be in order to present a balanced
representation of this technology. It will also be used to
explain the role of semiconductors in the filtration process.
L. Pastrana-Martíneza, S. Morales-Torresa, V. Likodimosb,
J. L. Figueiredoa, J. L. Fariaa, P. Falaras. (2012). “Advanced
Nanostructured Photocatalysts Based on Reduced Graphene
Oxide–TiO2
Composites
for
Degradation
of
Diphenhydramine Pharmaceutical and Methyl Orange Dye.”
Applied Catalysis B: Environmental. (Online Article).
http://www.sciencedirect.com/science/article/pii/S09263373
12001920
This paper, published by Elsier in a textbook on applied
catalysis, presents experiments done with TiO2 and
graphene that show the pair’s ability to filter hazardous
water pollutants, pharmaceuticals, and MO azo-dye. The
paper also shows how TiO2 can be used most effectivity
under UV irradiation. This article will be used to provide
B. Jennings, K Kintzele, P. Heltne. (2009, August).
“Principles of Water Ethics.” Center for Humans and
Nature.
(online
article).
http://www.humansandnature.org/principles-of-water-ethics
This article, published by the Center for Humans and
Nature and written by experts on ethics including Kathryn
Kintzele, presents the ethical implications of water
distribution. It also presents factors that must be considered
when confronting this conflict including the common good,
responsible stewardship, and respect for human dignity.
This will be useful in presenting TiO2 as an answer to the
2
Tristan Abraham
Christina Rogers
ethical dilemma currently faced by the world due to a lack of
clean water.
C. Dougherty. (2015). “Tap Into It.” Environmental
Protection Agency. (Government Information Packet).
http://nepis.epa.gov/Exe/ZyNET.exe/200024QJ.txt?ZyActio
nD=ZyDocument&Client=EPA&Index=1995%20Thru%201
999&Docs=&Query=&Time=&EndTime=&SearchMethod=
1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYea
r=&QFieldMonth=&QFieldDay=&UseQField=&IntQField
Op=0&ExtQFieldOp=0&XmlQuery=&File=D%3A%5CZY
FILES%5CINDEX%20DATA%5C95THRU99%5CTXT%5
C00000015%5C200024QJ.txt&User=ANONYMOUS&Pass
word=anonymous&SortMethod=h%7C&MaximumDocuments=1&FuzzyDegree=0&ImageQuality
=r75g8/r75g8/x150y150g16/i425&Display=p%7Cf&DefSee
kPage=x&SearchBack=ZyActionL&Back=ZyActionS&Bac
kDesc=Results%20page&MaximumPages=1&ZyEntry=2
This government information packet
provides
information about water standards and presents the overall
effectiveness of TiO2 filtration in objective and plain terms.
An understanding of government standards will allow us to
determine if water filtered using this process is pure enough
to be considered by the Environmental Protection agency of
the United States government as safe. This in turn will
provide legitimacy to the filtration process of TiO2 and
graphene.
H. Zhang, X. Lv, Y. Li, Y. Wang, J. (2009, December).
“P25-Graphene Composite as a High Performance
Photocatalyst.” ACS Publications. (Academic Journal).
http://pubs.acs.org/doi/abs/10.1021/nn901221k
This academic journal, published by the American
Chemical Society, discusses the use of Graphene as a
photocatalyst. This application of graphene is discussed in
the technical detail needed to fully present graphene filters
and their applications. This article will be used to explain
what makes graphene an effective filter as well as explain
why advances in technology have significantly reduced
costs.
“Evaluation of the Costs and Benefits of Water and
Sanitation Improvements at the Global Level.” (2015). The
World
Health
Organization.
(Online
Article).
http://www.who.int/water_sanitation_health/wsh0404summa
ry/en/
This report published by the World Health Organization
details the economic benefit of investment in clean water.
This article will be used to justify the initial costs of setting
up large-scale graphene filtering by presenting the net
economic benefit of that investment. Providing this data to
readers of our papers adds relevance to the topic as well as
increases its potential appeal.
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