The Pennsylvania State University The Graduate School Department of Civil and Environmental Engineering CRUDE OIL AND FUEL SPILL CLEAN UP BY USING EXFOLIATED GRAPHITE ENVELOPED IN SPUN POLYOLEFIN A Thesis in Environmental Engineering by Fatih Temiz 2014 Fatih Temiz Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science May 2014
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The Pennsylvania State University
The Graduate School
Department of Civil and Environmental Engineering
CRUDE OIL AND FUEL SPILL CLEAN UP BY USING
EXFOLIATED GRAPHITE ENVELOPED IN SPUN POLYOLEFIN
A Thesis in
Environmental Engineering
by
Fatih Temiz
2014 Fatih Temiz
Submitted in Partial Fulfillment of the Requirements
for the Degree of
Master of Science
May 2014
The thesis of Fatih Temiz was reviewed and approved* by the following:
Frederick S. Cannon Professor of Environmental Engineering Thesis Advisor
John M. Regan Professor of Environmental Engineering
Rachel A. Brennan Associate Professor of Environmental Engineering William Burgos Professor of Environmental Engineering and Professor in Charge of Graduate Programs
*Signatures are on file in the Graduate School
iii
ABSTRACT
This paper is aiming to address the problem of oil spills occurring on water bodies. 81%
of oil spills that occur are less than 50 US barrels in volume and these are considered as minor
spills. There is no perfect solution for this problem and oil spills are a real threat to nature. As an
alternative way of combating smaller scale oil spills, Exfoliated Graphite (EG) is being examined.
Production temperature of Exfoliated Graphite is effective in the oil capturing capacity and it is
covered by results gathered from tests. The higher the exfoliation temperature, the more surface
area Exfoliated Graphite gains, so this large surface area makes it possible to capture petroleum
products and hold it. To see the capturing efficiency of Exfoliated Graphite, motor oil, gasoline
and diesel fuel mixture, Texas crude oil and Pennsylvania crude oil were used in the experiments.
Also, the material was tried in fresh water and sea water.
Additionally, a product is designed for real life application purposes which consists of
Exfoliated Graphite and an envelope made from Spun Polyolefin (PO, cap). Other envelope
materials were also used (fiberglass, tulle, ribbon, artificial silk). In addition to the tests that
Exfoliated Graphite was tried in, pumps were put in a water tank and surface of water was
agitated to see how the product would act in such quiescent and turbulent conditions. These tests
consisted of 20 cycles and each cycle consisted of 10 minute dipping, then squeezing, weighing,
and again dipping. In an attempt to mimic similar conditions in a quiescent area, such as a harbor,
5-second dripping readings were noted, once the pouch was taken out of the water tank with oil in
it, the pouch was left to drip for 5 seconds. These tests with Exfoliated Graphite enveloped in
Spun Polyolefin pouches gave 37 g gasoline and diesel fuel mixture (50-50 by volume) / g pouch;
54 g Texas crude oil / g pouch; and 59 g motor oil / g pouch. When these data were further
analyzed, individual contributions of Spun Polyolefin and Exfoliated Graphite were calculated.
iv
So, for motor oil capturing, 35 g oil / g Spun Polyolefin was achieved and 115 g oil / g Exfoliated
Graphite efficiency was attained.
Experiment data also showed us that when Exfoliated Graphite is enveloped within Spun
Polyolefin, the envelope material, Spun Polyolefin, rebounded with 97% of its first-cycle oil
retention capacity, while the Exfoliated Graphite rebounded with 65% of its first-cycle oil
retention capacity in motor oil capturing tests.
By the end of 20 cycles of motor oil loading and squeezing, the caps had captured 1,105
g oil in total and pouches had captured 1,698 g oil in total giving 395 g oil / g PO and 606 g oil /
g EG+PO efficiency values, respectively. For 50-50 by volume gasoline and diesel fuel mixture
tests, 875 g oil was captured by EG+PO pouches at the end of 20 cycles (364 g oil / g EG+PO)
and 622 g oil was captured by PO alone (259 g oil / g PO). In the Texas crude oil tests, the pouch
removed 1105 g crude oil (790 g oil / g EG+PO) and PO removed 1,131 g crude oil (808 g oil / g
PO) after 20 cycles of 5-second dripping readings.
v
TABLE OF CONTENTS
List of Figures .......................................................................................................................... vi
List of Tables ........................................................................................................................... ix
Acknowledgements .................................................................................................................. x
Figure 2-2. Normalized Expansion Volume versus Temperature of Formation (Moustafa, 2009) ................................................................................................................................ 16
Figure 2-3. Mass Gain of Exfoliated Graphite by Temperature It Was Formed (Moustafa, 2009) ................................................................................................................................ 17
Figure 2-4. Average Mass Gain versus Normalized Expansion Volume ................................ 17
Figure 2-5. Left – Polyolefin, Right – Polyolefin Gel (Methods and Compositions for
Absorbent for Hydrocarbon Recovery) ............................................................................ 19
Figure 3-1. Preparation of the Product, Spun Polyolefin and Exfoliated-Graphite-800 .......... 23
Figure 3-2. Water Tank Surface Diagrams with Maximum Wave Amplitudes, from Left to Right: 1-Pump, 2-Pump, and 3-Pump Test Plans ........................................................ 24
Figure 3-3. Oil Recovery by Mechanical Means (Pouch Squeezing) ...................................... 25
Figure 3-4. Polyolefin and Exfoliated Graphite Mixture Preparation ...................................... 29
Figure 4-1. Water Tank 5-Second Drip Oil Capture Tests with Cap (1.3-1.5 g PO) versus Pouch (0.9-1.0 g PO + 0.3-0.4 g EG) in 200 mL Motor Oil, Fully Turbulent Water ...... 34
Figure 4-2. Total Oil Capture Graph for Water Tank 5-Second Drip Tests with Cap (1.3-1.5 g PO) versus Pouch (0.9-1.0 g PO + 0.3-0.4 g EG) in 200 mL Motor Oil, Fully Turbulent Water ............................................................................................................... 34
Figure 4-3. Water Tank 40-Second Drip Oil Capture Tests with Cap (1.3-1.5 g PO) versus Pouch (0.9-1.0 g PO + 0.3-0.4 g EG) in 200 mL Motor Oil, Fully Turbulent Water ................................................................................................................................ 35
Figure 4-4. Total Oil Capture Graph for Water Tank 40-Second Drip Tests with Cap (1.3-1.5 g PO) versus Pouch (0.9-1.0 g PO + 0.3-0.4 g EG) in 200 mL Motor Oil, Fully Turbulent Water ............................................................................................................... 36
Figure 4-5. Water Tank 5-Second Drip Oil Capture Tests with Cap (0.6-0.8 g PO) versus Pouch (0.6-0.9 g PO + 0.3-0.5 g EG) in 200 mL Motor Oil, Turbulent Water ................ 36
Figure 4-6. Total Oil Capture Graph for Water Tank 5-Second Drip Tests with Cap (0.6-0.8 g PO) versus Pouch (0.6-0.9 g PO + 0.3-0.5 g EG) in 200 mL Motor Oil, Turbulent Water ............................................................................................................... 37
Figure 4-7. Water Tank 40-Second Drip Oil Capture Tests with Cap (0.6-0.8 g PO) versus Pouch (0.6-0.9 g PO + 0.3-0.5 g EG) in 200 mL Motor Oil, Turbulent Water .... 38
vii
Figure 4-8. Total Oil Capture Graph for Water Tank 40-Second Drip Tests with Cap (0.6-0.8 g PO) versus Pouch (0.6-0.9 g PO + 0.3-0.5 g EG) in 200 mL Motor Oil, Turbulent Water ............................................................................................................... 38
Figure 4-9. Water Tank 5-Second Drip Fuel Capture Tests with Cap (1.0-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.4 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Fully Turbulent Water ............................................................................................. 39
Figure 4-10. Total Fuel Capture Graph for Water Tank 5-Second Drip Tests with Cap (1.0-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.4 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Fully Turbulent Water ................................................................... 39
Figure 4-11. Water Tank 40-Second Drip Fuel Capture Tests with Cap (1.0-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.4 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Fully Turbulent Water ............................................................................................. 40
Figure 4-12. Total Fuel Capture Graph for Water Tank 40-Second Drip Tests with Cap (1.0-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.4 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Fully Turbulent Water ................................................................... 40
Figure 4-13. Water Tank 5-Second Drip Fuel Capture Tests with Cap (1.1-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.3 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Turbulent Water ...................................................................................................... 41
Figure 4-14. Total Fuel Capture Graph for Water Tank 5-Second Drip Tests with Cap (1.1-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.3 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Turbulent Water ............................................................................ 42
Figure 4-15. Water Tank 40-Second Drip Fuel Capture Tests with Cap (1.1-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.3 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Turbulent Water ...................................................................................................... 43
Figure 4-16. Total Fuel Capture Graph for Water Tank 40-Second Drip Tests with Cap (1.1-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.3 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Turbulent Water ............................................................................ 43
Figure 4-17. Water Tank 5-Second Drip Crude Oil Capture Tests with Cap (1.4 g PO) versus Pouch (1.0 g PO + 0.5 g EG) in 200 mL Texas Crude Oil, Fully Turbulent Water (Oil Only, Fixed According to Water Capturing Values from Cycles 21-25)....... 44
Figure 4-18. Total Crude Oil Capture Graph for Water Tank 5-Second Drip Tests with Cap (1.4 g PO) versus Pouch (1.0 g PO + 0.5 g EG) in 200 mL Texas Crude Oil, Fully Turbulent Water ...................................................................................................... 44
Figure 4-19. Water Tank 40-Second Drip Crude Oil Capture Tests with Cap (1.4 g PO) versus Pouch (1.0 g PO + 0.5 g EG) in 200 mL Texas Crude Oil, Fully Turbulent Water (Oil Only, Fixed According to Water Capturing Values from Cycles 21-25)....... 45
viii
Figure 4-20. Total Crude Oil Capture Graph for Water Tank 5-Second Drip Tests with Cap (1.4 g PO) versus Pouch (1.0 g PO + 0.5 g EG) in 200 mL Texas Crude Oil, Fully Turbulent Water ...................................................................................................... 46
Figure 4-21. Water Tank 5-Second Drip Fuel Capture Tests with Cap (1.0 g PO) versus Confined Pouch (0.5 g PO + 0.5 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Fully Turbulent Water ............................................................................................. 46
Figure 4-22. Water Tank 40-Second Drip Fuel Capture Tests with Cap (1.0 g PO) versus Confined Pouch (0.5 g PO + 0.5 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Fully Turbulent Water ............................................................................................. 47
Figure 4-23. Water Tank 5-Second Drip Oil Capture Tests with Cap (1.0 g PO) versus Confined Pouch (0.5 g PO + 0.5 g EG) in 200 mL Motor Oil, Fully Turbulent Water ... 48
Figure 4-24. Water Tank 40-Second Drip Oil Capture Tests with Cap (1.0 g PO) versus Confined Pouch (0.5 g PO + 0.5 g EG) in 200 mL Motor Oil, Fully Turbulent Water ... 48
Figure 4-25. Tests for Determining Water Capturing Percentages .......................................... 51
Figure 4-26. Polyolefin Oil Capturing Tests for 2 Hours in 10 mL of Motor Oil on 100 mL of Water ..................................................................................................................... 59
Figure 4-27. Polyolefin Oil capturing Tests in 10 mL of 50-50 Gasoline and Diesel Fuel Mixture on 100 mL of Water ........................................................................................... 60
Figure 4-28. Pouch Materials: a) Tulle b) Fiberglass c) Silk Screen d) Ribbon ...................... 62
Figure 4-29. Spun Polyolefin Oil capturing Test for 5 Minutes in 20 mL of 50-50 Gasoline and Diesel Fuel Mixture on 100 mL of Water .................................................. 63
Figure 4-30. Spun Polyolefin Oil capturing Test for 5 Minutes in 20 mL of Motor Oil on 100 mL of Water .............................................................................................................. 63
Figure 4-31. Spun Polyolefin Pouch Oil Capturing Tests Run for 3 Minutes in 10 mL of 50-50 Gasoline and Diesel Fuel Mixture on 100 mL of Water ........................................ 64
Figure 4-32. Spun Polyolefin (Previously Dipped in Soapy Water) Pouch Oil Capturing Test for 3 Minutes in 40 mL of 50-50 Gasoline and Diesel Fuel Mixture on 100 mL of Water............................................................................................................................ 65
Figure 4-33. Exfoliated-Graphite-800 Only Oil Capturing Tests in 20 mL of 50-50 Gasoline and Diesel Fuel Mixture and Motor Oil on 100 mL of Water .......................... 66
Figure 4-34. Exfoliated-Graphite-800 Only Oil capturing Test in 50-50 Gasoline and Diesel Fuel Mixture on 100 mL of Water for 5 Minutes by Grid Filter Protocol ............ 67
ix
LIST OF TABLES
Table 1-1. World Maritime Operational and Accidental Sources of Crude Oil Entering Water Bodies (Ketkar and Chair, 2005) ........................................................................... 2
Table 1-2. Quantity of Oil Spilled (Statistics by ITOPF) ........................................................ 3
Table 2-1. Appearance Properties of Oil Slicks (ASTM F 2534-12) ...................................... 8
Table 3-1. Artificial Sea Water Composition (ASTM D 1141-98) ......................................... 30
Table 4-1. Water Capturing Percentage Values for Confined Pouch Tests ............................. 49
Table 4-2. Water Capturing Percentage Values for Texas Crude Oil Tests - Cycles 21-25 .... 49
Table 4-3. The Least Significant Difference (LSD) Comparison Chart .................................. 50
Table 4-4. Average Oil Capturing and Average Efficiency for the Whole Test Set ................ 51
Table 4-6. Pouch Material and Polyolefin Hydrocarbon Capturing Tests ............................... 57
Table 4-7. Water and Oil Product Oil and Water Capturing Test Results Run for 10 Minutes for Envelope Materials on 100 mL of Water Only for Water Capturing Test and 100 mL of Water and 10 mL of Oil Product in Oil Capturing Tests ......................... 61
x
ACKNOWLEDGEMENTS
This thesis and my study program were sponsored and supported by Ministry of National
Education of Turkey and Turkish Petroleum Corporation (TPAO). I would like to thank and
present my regards to both parties.
My supervisor Dr. Fred S. Cannon and the Cannon group members were very helpful
during my study period.
The last but not the least, I would like to thank my friends and my family for their
continuous support.
1
Chapter 1
Introduction
Extraction of crude oil does not always occur where it is consumed the most, in fact,
crude oil travels around the world to its final destination. There are various ways of transport for
crude oil, such as, pipelines, tankers, motorway carriage, and railway carriage. Ketkar and Chair
mention about crude oil transportation methods in Water Encyclopedia and they suggest that due
to its relative cheapness and heavy carriage capacity tankers are preferred for the transport of
crude oil. Use of oil tankers as a means of transportation only became in the second half of the
19th century. The event that took place in December 1861 changed the general course of transport
on the seas: The Elizabeth Watts vessel carried kerosene from Philadelphia to London across the
Atlantic (Akaki, 2011). As more tankers made their way on the seas, a new source of pollution
was bred. During filling up the tankers, while navigating on the seas or while emptying the crude
oil that is being carried generate pollution.
The sort of pollution occurring is a result of anthropogenic actions as the liquid form of
petroleum is discharged into the environment, this kind of pollution chiefly affects the seas.
Marine crude oil spills can happen in open seas or in coastal waters. Accidental or intentional
discharge of crude oil from tankers, offshore platforms, oil rigs, oil wells, ships, or from waste
waters are the general sources of crude oil pollution. Run off from polluted areas also cause
marine crude oil pollution. In the beginning, crude oil pollution will meet ponds, rivers, lakes or
other small water bodies but as time passes these pollutants will make their way to the oceans.
Additionally, there are natural ways of crude oil pollution like oil seepages from natural deposits
(Ketkar and Chair, 2005).
2
The term oil includes hydrocarbons which are crude oil, fuel oil, gasoline, heating oil,
diesel fuel, jet fuel, and other refinery products. Oil may make its way straight into waters and
may seep into and found in ground waters. Water bodies have a natural ability to clean and treat
themselves by biological, physical and chemical ways (microorganism, wind, sun light, etc.
contribute to natural oil cleaning up); however, when these natural ways are not sufficient then oil
pollution becomes a problem. Oil tanker accidents and pipeline disasters are the ways that attract
most responsiveness by the public and hence the media, this is due to the fact that a large amount
of oil enters the water body in a very short period of time. More than 26.5 million liters of crude
oil was spilt after the accident of the Exxon Valdez in Alaska in the year 1989 (Leacock, 2005).
The ocean protection foundation Oceana states that the vast majority of crude oil
reaching the seas comes from inland operations (80%), and this share is made up of 44% of direct
discharge, 33% transportation in atmospherically paths, and 20% of accidental and intentional
discharge from ships and marine amenities (Ketkar and Chair, 2005).
Table 1-1. World Maritime Operational and Accidental Sources of Crude Oil Entering Water Bodies (Ketkar and Chair, 2005)
Source Crude Oil Entering Water Bodies (million tons/year)
1990 1981-1985 1973-1975
Bilge and fuel oil 0.25 0.31 n/a
Tanker operational losses 0.16 0.71 1.08
Tanker accidents 0.11 0.41 0.20
Non-tanker accidents 0.01 n/a 0.10
Marine terminal operations 0.03 0.04 0.50
Dry-docking 0.01 n/a n/a
It is known that the effect of oil spills depends on some factors - kind of oil, spilled
volume, climate, location and the season; and the combat against oil spills has proven that
3
majority of countries are not equipped sufficiently for such a response (Heubeck et al., 2003).
Small and medium scale spills are more common. The International Tanker Owners Pollution
Federation (ITOPF) states that 81% of oil spills are minor spills, which are less than 50 US
barrels. Furthermore, ITOPF lists the quantity of oil spilled as follows. In the table below, it can
be clearly seen that quantity of oil spilled by tankers becomes less over the decades.
Technological advancements and with the growing environmental sensitivity this improvement
happened (itopf.com).
Table 1-2. Quantity of Oil Spilled (Statistics by ITOPF)
Years Oil Spilled (tons)
1970 - 1979 3,218,000
1980 - 1989 1,176,000
1990 - 1999 1,135,000
2000 - 2009 212,000
2010 - 2012 14,000
There are chemical, biological and physical methods, or a combination of these methods,
for cleaning up the crude oil spills. From these oil spills, harbors are affected by what the vessels
are using as their fuel and lubricants for moving parts of their machinery. As it can be seen in
various news stories diesel fuel spills, such as in New Bedford, Massachusetts (The Boston
Globe, August 29, 2013), and Ventura Harbor, California (United States Coast Guard News
Release, Nov. 19, 2013), happen in harbor areas. Additionally, where vessels berth are also prone
to motor oil spills, for example, as in Oak Bluffs, Massachusetts (Vineyard Gazette, November
20, 2013), and bilge water problems which brought up environmental concerns in Monterey Bay,
California (saveourshores.org). Whereas the larger and catastrophic spills like the Deepwater
Horizon incident take place in open waters.
4
Oil pollution occurred before, is occurring at the moment and will occur in the future.
Alternative methods of combating against oil spills have been proposed. The method suggested in
this paper will be a physical clean up method by using Exfoliated Graphite enveloped in Spun
Polyolefin. Oil can get in Exfoliated Graphite and the material expands. Exfoliated Graphite can
sorb much oil and Spun Polyolefin participates in oil and fuel capturing. The objectives of the
study are developing a product which can be used in oil spill areas and make tests in the water
tank with turbulence to mimic conditions that would be faced in the real life applications.
Exfoliated Graphite works so well because space between layers expands further as oil
gets in, the capillary action within Exfoliated Graphite pulls oil even further and the weak forces
between Exfoliated Graphite layers makes the further expansion possible.
Enveloped Exfoliated Graphite would be more practical to use than being applied on its
own because it is lightweight and in a windy condition it would be drifted away, enveloping it
would make the handling easier. The good signs for an envelope material is it being sturdy,
having a small mesh size to keep Exfoliated Graphite inside the pouch formed, also help oil
capturing, and being flexible so it does not crush Exfoliated Graphite and let it expand and not
limit it and we hypothesize that we can find an envelope material for Exfoliated Graphite
showing these favorable properties.
Chapter 2
Literature Review
Environmental Effects of Oil Spills
Obviously, crude oil pollution has its effects in the environment. Animals are affected as
they are covered by the crude oil, hence losing their aviation capability or eye sight, having
internal organ damages especially in their kidneys and livers. Marine living beings are affected
from the floatation of crude oil as it cuts the oxygen contact and sunlight penetration into the
water. Also, coast lines suffer from the pollution as they are covered and the natural balance is
being altered.
As Reis (1996) mentions, there is a natural way of degradation of crude oil, with respect
to the amount and kind of oil spilled, the natural conditions, temperature, depth and other
properties of the water body, leaving the spillage on its own may be preferred.
Crude oil floats on water and with the movement of water and with the wind it will travel
very rapidly; therefore, it must be contained by booms and engulfed as soon as possible. The
lighter the oil product the faster it will travel, i.e. gasoline would travel faster than crude oil
(Mohan et al., 2005). Accordingly, collecting the stack of oil, preventing further damages to the
environment and keeping waste production in minimum are the purposes of cleaning up practices
while making use of existing conditions and assets safely, efficiently and effectively (General Oil
Spill Response Plan by ESSO).
In addition, booms age and become useless in crude oil pollution combating. The boom
skirt deformation reduces the boom draft; hence it reduces its effectiveness (Lee, 1997). This
6
physical method of enveloping crude oil needs to be supported by a sorbent material in order to
remove crude oil from water.
Bayat et al. (2005) also mention about an alternative way of treatment which is called
bioremediation. Enzymes of some microorganisms found in seawater have the ability to break
down oil products. This kind of treatment is executed by introducing these living organisms to the
polluted area or by stimulating the ones that live in the polluted area already. Since living beings
require many nutrients and ideal conditions to live (temperature, wind, sunlight, wave currents,
oxygen, etc) and to operate, the process is slow and oxygen amount is often a limiting regent in
bioremediation (Bayat et al., 2005).
There are many factors to be considered when an oil spill occurs. For example, Alaska
North Slope crude oil's weathering was lethal to the fish in their larvae stage. However, with the
short northern day, the sun light made the lethality of the oil up to almost 50 times worse (Barron
et al., 2003). Furthermore, an oil spill affects many species of animals and plants. As Burger
suggests, this results in a halt in the healthy performance of the ecosystem, although not all
ecosystems act the same. A simple ecosystem's suffering in the long run might be greater than an
intricate ecosystem (Oil Spills, pp. 87-88).
In the year 1993, oil wells and storage tanks were destroyed during the armed conflict
during the First Gulf War. This attack led to nearly 1 billion liters of crude oil (when comparing it
to the Exxon Valdez incident, it can be seen that this latter event is catastrophic, standing at
almost 38 times more release of hydrocarbons to the environment) to be released into the Persian
Gulf (Bayat et al., 2005). Saddam Hussein's, former president of Iraq, attacks caused more than
700 wells in Kuwait to be damaged and the oil well fires consumed an estimated amount of 1.5
million barrels and perhaps as high as high 4 million barrels a day (Riva, 1991). Other observers
claim the Persian Gulf was only polluted by 2 to 4 million barrels and not by more than 10
million barrels unlike in earlier estimates (Khordagui and Al-Ajmi, 1993).
7
These attacks were done on purpose to damage the economy of Kuwait. The vast amount
of crude oil covered the waters for a long time virtually destroying the habitat around, therefore, it
can be concluded that the environmental effects of these attacks were much worse than their
economical effects. The winds carried particles caused by fires and this deteriorated the air
quality along Bahrain's and Saudi Arabia's shores on the Persian Gulf. Inhalable particulate
concentrations in the air (340 µg/m3 once in a year is the standard limit set by the local the
Meteorology and Environmental Protection Administration) was measured to be as high as 3,294
µg/m3 in one station (Husain and Amin, 1994).
More recently, The Deepwater Horizon oil spill which started on April 20, 2010 and
continued till July 15 in the same year (On Scene Coordinator Report Deepwater Horizon Oil
Spill) drew attention to major oil spill incidents in the US and worldwide. The Deepwater
Horizon oil spill affected the health of common bottlenose dolphins. The study compared the
dolphins in Barataria Bay, Louisiana, where the area was heavily affected by the catastrophic oil
spill and in Sarasota Bay, Florida, where the spill did not reach. Nearly half the dolphins
examined in Barataria Bay were expected to have worse health in the future and about one-sixth
of them were expected to die (Schwacke et al., 2014).
In order to combat an oil spill, it is necessary to estimate how much oil is spilled. This
estimation step is needed to predict the amount of sorbent material to be used. ASTM Standard
for Visually Estimating Oil Spill Thickness on Water (ASTM F2534-12) gives the values for
estimating the thickness of film and hence the volume of the spill by multiplying the surface area
of the spill by the thickness of the film.
8
Table 2-1. Appearance Properties of Oil Slicks (ASTM F 2534-12)
Visibility Characteristics
Values Minimum
Observable Thickness (µm)
Minimum Onset Thickness (µm)
Silvery Rainbow Dark
Rainbow Dark
Typical 0.08 0.1 0.5 3 > 3
Range 0.05 - 0.2 0.1 - 0.3 0.2 - 3 > 3
Using Sorbent Materials for Cleaning Up Crude Oil Spills
Sorbent materials can be added while fighting against crude oil spills. The addition of
sorbents transforms liquid phase crude oil to a semi-solid form and the procedure of removal gets
easier. The hydrophobic and oleophilic features of sorbents are the specialties of these materials
that make them work efficiently. Other noteworthy points are the recoverability of crude oil from
the sorbent, whether the sorbent is biodegradable and if the sorbent can be used again (Teas et al.,
2001).
A survey was undertaken and explained in “Investigation of the effectiveness of sorbent
materials in oil spills clean-up” in which sorbents were used to capture oil from artificial
seawater. This artificial seawater was prepared according to ASTM D-1141 standard. Samples of
sorbent were experimented by adding into a water and oil body. The body was mobile by making
98 cycles in a minute. The weight of the sorbent-water-and-oil was read on the scale and then the
weight of water and the weight of the sorbent were reduced from the reading, and this gave a ratio
of sorbent per oil captured; and these procedures were completed according to ASTM D-95
standard. The findings of this study suggest that more viscous crude oil can be captured more
easily; however, as oil’s viscosity increases the rate of oil capturing is limited and the rate of oil
capturing within pores and capillaries of the sorbent material is lessened (Teas et al., 2001).
9
Next, the effectiveness of sorbents also depend on various matters: economic viability
(being relatively cheaper to make it, low application costs), engineering features (availability of
being mass produced, operation ability), achievement issues (superior oil capturing rates, not
sinking on water, reclaiming of oil from the sorbent, elongated use), environmental friendliness,
other concerns (chemical and magnetic properties, response to natural decay, etc.) (Mahajan,
2011).
With the advancements in nanotechnology, there are more sorbent options to be used in
oil spills. In Nanotech Insights some of these carbon nanostructures (Exfoliated Graphite, carbon
nanotube sponge, vertically aligned carbon nanotubes, graphene worms and nano-accordions,
RECAM (reactive carbon material) technology, high reactivity carbon mixtures) are listed. Also
cotton absorbents are included in the list, yet, these are hydrophilic materials that capture water as
well as water. Magnetic materials (magnetic carbon composites, magnetic nanocomposites,
hydrophobic magnetic nanoparticles, magnetic polymer nanocomposites, organoclays with
magnetic nanoparticles, magnetic liquid foams) are in the list as well, magnetic properties are
added to these materials to make the collecting from the surface of oil spill easier, however, their
oil capturing efficiency is not enhanced (Mahajan, 2011).
It is also known that there are naturally occurring and organic materials that can be used
for oil spill cleanup purposes, such as straw, corncob, wood fibers, cotton fibers, kapok fibers,
kenaf fibers, milkweed floss, peat moss (Adebajo et al., 2003). Additionally, raw jute is also used
in the same sense. Raw jute was seen to have a oil capturing rate of about 2.6 g of machine oil per
gram of raw jute, however, when it was modified under the process of acetylation its sorbance
capacity increased by more than 8 times, also, the liquid captured was recovered by squeezing
manually and with machinery (Teli and Valia, 2013). Woodchips, eucalyptus, wheat straw
(hydrophilic substances), polypropylene (not hydrophilic) were suggested to be used in oil spill
cleanup processes as these materials were abundant in agricultural areas, these materials
10
performed differently in different kinds of oils used, yet polypropylene gave best oil capturing
rate results (Teas et al., September 2001).
Another material used in this problem is biochars. Biochars that are made up of wood are
also used as sorbents in oil spill cleanup combating. A study used these products in salty water.
Although the salty water aided oil capturing rate of biochars weathering of oil decreased the
efficiency of oil capturing (Nguyen and Pignatello, 2013). Similar conditions are applied on the
materials used in this study in order to find how these problems would affect the performances.
In addition, mineral based products are also used for similar purposes. For example,
expanded perlite was used in oil spill cleanup with aid of emulsifiers (Roulia et al., 2003). Also,
experiments were conducted in solvents like xylene, pentane and toluene with zeolite socony
mobil-5, mordenite and faujasite zeolites by making use of their hydrophobic behavior
(Meininghaus and Prins, 2000).
An additional attempt for oil spill cleanup was producing magnetic polymers. A
biopolymer was treated where maghemite was available. The result was an oil capturing rate of 8
times the mass of the polymer (Gomes de Souza et al., 2010).
Furthermore, it is also suggested that using some of the sorbents together gives a more
viable operation option. Such as, use of activated carbon and organoclays together is
recommended by researchers (Adebajo et al., 2003). The same research also mentions that
polypropylene and polyurethane are commonly used in oil spill cleanup and these materials'
capturing capacity can be increased by further studies of adding additional natural materials to
them, yet, polypropylene and polyurethane are not biodegradable and this brings problems
(Adebajo et al., 2003).
The last but not the least, people with their well meaning, after seeing the oil spill
accidents or catching the news about them, tried to be a part of the solution. The Exxon Valdez
oil spill even brought ideas like using feathers, popcorn, towels and cheese to cleanup oil (Times
11
Daily). A hairdresser gathered human hair (Hair-raising idea) after seeing a sea mammal's fur
soaked with oil, moreover, some groomers collected cat and dog hair to be used in this event
(McClatchy - Tribune Business News). The human hair usage idea was also implemented in the
Philippines where prisoners donated their hair in 2006 to help an oil spill response
(nbcnews.com). Yet, once again, after the Deepwater Horizon catastrophe human hair, pet hair
clippings and sheep wool were used aiming to stop oil from reaching the shores (bbc.co.uk).
Chemical Dispersant Usage in Oil Spill Clean Up
Chemical dispersants have polar features and these chemicals are manufactured to help
lubricating fluids in moving parts of the engines (Seddon et al., 2010). Another use of dispersants
is in the process of oil spill cleanup.
In the year 1989, it was suggested by the National Research Council in the US that
chemical dispersants could be used in oil spill combating (Kearney, 2005). As a quick response,
in some occasions, chemical dispersants are applied to water bodies after oil spills. Nearly 3
million liters of chemical dispersants were applied after the Deepwater Horizon oil spill. This
application took place in deep water, however, there were no uses of deep water applications of
chemical dispersants before this incident (Kujawinski et al., 2014). On the other hand, another
author claims nearly 7.5 million liters of these chemicals might have been used after the accident
happened (Biello, 2010). The study of Kujawinski et al. (2014) showed that the dispersant used in
the surface and in deep waters did not react, besides, the deep water application did not seem to
be going under biodegradation or only in minor speeds.
After the Deepwater Horizon oil spill, the dispersant industry conducted tests to show the
effects of dispersant use. Later, EPA contributed to the discussion and came up with similar
12
results as the industry that the chemicals affected some fish and shrimp species but did not
distress the endocrine systems of the organisms around to a great extent (Biello, 2010). However,
the same author's report states that Sergio A. Villalobos, the manufacturer of one of the
dispersants used in the Mexican Gulf, said that the upshot of toxic results appear when the
dispersant and oil get blended (Biello, 2010).
A study covering the oil spill response in Europe between years 1995 and 2005 shows
that in majority of the oil spills chemical dispersants were not applied. This lack of usage is
claimed to be due to conditions that would lower the efficiency of dispersants. The study also
notes that more research on the effects of dispersants is sought by some countries and approach of
some countries change as Net Environmental Benefit Analysis results come to the surface
(Chapman et al., 2007).
In a study conducted in Alaska, it was observed that oil and dispersant mixture had the
same lethality rate as oil alone. However, under sunlight the mixture of dispersant and oil became
a lot more toxic. Polycyclic aromatic hydrocarbons became more soluble by the dispersant. Also,
the rate of this transition actually became speedier (Barron et al., 2003). Moreover, in a warmer
climate, a study on coral reefs showed that dispersants had lethal effects on these organisms when
they were applied according to the manufacturer's manual (i.e. the suggested concentration level)
after a 1-day contact; the same group also reported that dispersants and dispersant-treated crude
oil were more toxic than the water soluble parts of crude oil (Shafir et al., 2007). Their latter
finding is also supported by the publishing of Toxic Effects of Some Oil Dispersants (Riepsaite
and Stankevicius, 2005) as the authors suggested toxicity of dispersants is less than the toxic
effects of crude oil, yet, when they are together their overall damage is even greater.
On the contrary, some scientists claim the use of dispersants actually made the impact of
oil spills to the nature smaller. Recent uses of dispersants which have smaller toxic effects are
13
more beneficial than not using them in oil spill response. They also help handling oils which were
not able to be dispersed by chemicals previously used (Lessard and DeMarco, 2000).
As the debate on chemical dispersants continue, this study will not be including them and
focus on physical and mechanical techniques in order to clean up oil spills from water bodies.
Using Exfoliated Graphite in Crude Oil Spills
Exfoliated Graphite is a material made from carbon as nanoparticles of graphite. This
material is a promising substance to be used in oil spill cleaning up. The maximum crude oil
capturing capacity reaches up to 82 kg crude oil per kg sorbent (Moustafa, 2009). In laboratory
Exfoliated Graphite works with a high efficiency, on the other hand, Exfoliated Graphite cannot
be applied onto the oil spill on its own since that would cause another uncontrolled pollution case.
When Exfoliated Graphite is packed into a fiberglass cover, crude oil capturing capacity of the
new package reached up to 68 kg crude oil per kg sorbent (Moustafa, 2009).
Since crude oil is currently one of the most consumed fossil fuels, it is extracted in oil
fields throughout the planet and crude oil is then transported to where it is refined and finally
consumed. During these extraction and transportation procedures, leakages, seepages, and
accidents occur which cause from minor to catastrophic amounts of crude oil to be spilled onto
the ground or water. With most of the crude oil being transported on sea routes, every single day
crude oil spills happen on the routes which affect the spill location and the surrounding area.
Type of oil product, volume of spill, distance from shores, hydro-geographical properties of the
sea, weather conditions, oceanographic properties, season of the year, emergency response
opportunities and the experience of the staff are all points affecting the severity of the oil spill
which may range from a minor incident to a worldwide catastrophe.
14
Exfoliated Graphite was applied on heavy oils in various studies, different results came
from them. However, all of these results are promising. It was found that Exfoliated Graphite was
sorbing heavy oil (specific gravity of 864 g/cm3 and viscosity of 0.4 kg.m-1.s-1 at room
temperature) at a rate of 83 times of its weight (Toyoda and Inagaki, 2003) also the same study
showed that oils with a lower viscosity were captured at a higher rate and in a shorter period of
time. The same paper also mentions that 70% of captured oil was regained by lowered pressure
filtration. This research team's earlier paper suggested a capturing rate of 86 times for heavy oil
and 76 times for crude oil of Exfoliated Graphite (Toyoda and Inagaki, 2000). Furthermore, even
an earlier study by Toyoda and his team suggested that the Exfoliated Graphite used in the study
reached a maximum sorbing capacity of more than 80 times of its weight. Not only that
Exfoliated Graphite can sorb the heavy oil, the oil was easily recovered by up to 80% only by
compressing the Exfoliated Graphite. The experiment was carried out in a laboratory but the
authors claim that this method can be used in open seas as well. Different oil types were poured
over distilled water and the combination was then shaken, as soon as the shaking finished, the oil
floated on water, and it was noticed that the distinctive brown color had also disappeared (Toyoda
et al., 1998).
Extremely serious oil tanker accidents occur on the seas, the point worsening the calamity
is that they carry and accidentally discharge heavy crude oil. The other thing is that the locations
where the accidents occur have windy and wavy conditions. In order to have an easier way of
collecting the Exfoliated Graphite applied on oil spills, some researchers developed magnetic
forms of Exfoliated Graphite. With this product prepared by adding cobalt ferrite, Exfoliated
Graphite's capturing capacity changed - better results for motor and crude oils, and worse results
for diesel fuel and gasoline (Wang et al., 2010).
In the study of Toyoda et al. (1998), it is suggested to focus on the following points for
further research: further studies on different grades of heavy crude oil; an easier way of handling
15
and using Exfoliated Graphite as it takes a very large volume although being very light; further
analysis of specialties of Exfoliated Graphite to have a better understanding for better oil product
capturing practices; introducing more efficient and easy to practice methods to recover oil
products from Exfoliated Graphite and recycling the sorbent.
The author tested the extent to which oil or fuel could be captured by packets of (a) Spun
Polyolefin alone (cap) or (b) Exfoliated Graphite enveloped by Spun Polyolefin (pouch). These
experiments included 0.6 g to 1.5 g of Spun Polyolefin (from bouffant caps), or 0.6 g to 1.0 g of
Spun Polyolefin enveloping 0.3 g to 0.5 g of Exfoliated Graphite (EG). These experiments
employed 200 mL of 10W-40 grade motor oil, a mixture of 100 mL of diesel fuel and 100 mL of
gasoline, or 200 mL of crude oil. The petroleum product was spilled on the water surface of the
water tank, the packets (pouch or cap) were dropped onto this surface, and then the packet was
extracted every 10 minutes to discern how much mass remained with the packet after 5 seconds,
then 40 seconds of dripping. Later, these packets were hand-squeezed, weighed, and then dropped
back on the water surface for a subsequent cycle of oil (or fuel) capture. These experiments
employed either fully turbulent water surface induced with 3 pumps that incurred 2.4 cm wave
heights across all the water surface or moderate turbulence induced with 2 pumps that induced 1.4
cm wave heights across two thirds of the tank surface. These dip-drip-weight and re-dip
experiments were conducted through 20 cycles; and were conducted in duplicates or triplicates.
When employing fully turbulent mixing and motor oil, the cap retained 36 g oil / g cap in
the first cycle, following 5-second drippings (Figure 4-1). Then during next cycles 2-8, the pooled
average for new oil captured was 28 g oil / g cap. Next, during cycles 9-20, the pooled average
for new oil capture was 17 g oil / g cap. These pooled values are presented as the heavy lines in
Figure 4-1. In comparison, the EG-PO pouch captured 59 g oil / g pouch in the first cycle, 37 g
32
new oil / g pouch as pooled average during cycles 2-8; and 27 g new oil / g pouch as pooled
average during the cycles 9-20. Both the cap and pouch experiments were conducted in duplicates
with the individual results (for a given cycle) shown as light solid lines; and the averages (for a
given cycle) shown as light dashed lines. The pouch data is presented in blue, and the cap data is
presented in red. Figure 4-1 also presents the least significant difference (LSD) to a 95%
confidence interval as a green bar; for the pooled 2-8 cycle data, and for the pooled 9-20 cycle
data. These least significant differences were 4 and 3 g/g respectively; which was considerably
less than the difference between the pooled averages for the pouches versus caps (9 and 10 g/g
respectively). Thus, these distinctions between the pouches and caps can be construed as
statistically true differences to the 95% confidence interval. Indeed, even at the 99.5% confidence
interval, these two pooled least significant differences are 7 and 4 g/g respectively; and thus, the
distinctions between the pouches and caps are truly different to the 95% confidence interval.
We further analyzed this data set to discern the individual contributions that the Spun
Polyolefin and Exfoliated Graphite offered for capturing the oil. Specifically, if we attribute the
same unit oil capture by the Spun Polyolefin that the cap alone had provided, then by mass
balance, we can attribute the rest of the oil capture to the Exfoliated Graphite. Hence, for Figure
4-1, during pooled cycles 2-8 the cap captured 27 g new oil / g Spun Polyolefin when normalized
to exclude the minimal mass of water sorption that included in Figure 4-1 (see below). So this
means that in the pouch experiments, this Spun Polyolefin could remove [27 g oil / g PO x 0.97 g
PO] 26 g oil. The total oil captured was [35 g oil / g (PO+EG) x 1.4 g (PO+EG)] 49 g oil. So, by
difference we can attribute to Exfoliated Graphite a capture of [(49 - 26) g oil / 0.4 g EG] 58 g
new oil / g EG. Additionally, when we evaluate the cycle 1, Spun Polyolefin could remove [35 g
oil / g PO x 0.97 g PO] 34 g oil, and the total oil captured was [59 g oil / g (PO+EG) x 1.4 g
(PO+EG)] 81 g oil, this difference can be attributed to Exfoliated Graphite a capture of [(81 - 34)
g oil / 0.4 g EG] 115 g oil / g EG. These unit mass capture values are presented in Figure 4-2.
33
We also appraise the extent to which these packets could rebound in their capacity to
capture oil. To characterize this, we have also identified the unit mass of oil that was retained
within the packets after a preceding cycle, even after the hand-squeezing step. For the cycles 2-8,
for the PO cap alone, this amounted to a rather consistent 35 g oil / g PO; and for the EG-PO
pouch, this amounted to 75 g oil / g (EG+PO). As the difference tells, this meant that EG retained
16 g oil / g EG during these cycles. So then, when comparing the cycle 1 data to the pooled cycle
2-8 data, the cap PO offered 35.4 g oil / g PO in the first cycle, compared to [(27.3 g new oil +
7.2 g non-squeezable oil) / g PO] 34.5 g total oil / g PO. Similarly, for the pouch, the new oil plus
retained oil amounted to 37 g total oil / g (PO+EG). Then, by difference the EG offered 75 g total
oil / g EG. When comparing these cycle 2-8 total oil capturing values to the cycle 1 values, we
note that the PO rebounded with 97% of its first-cycle oil retention capacity, while the EG
rebounded with 65% of its first-cycle oil retention capacity.
This is quite noteworthy and perhaps somewhat unexpected. We note that when the
pristine Exfoliated Graphite (that had not been exposed to petroleum products) was hand-
squeezed to the same pressure, and then immersed in oil, its oil capture capacity dropped to 75 g
total oil / g EG (see below). Thus, the motor oil offered important features in facilitating this
rebounding phenomenon and this is the important feature that renders these PO-EG packets to be
quite commercially useful.
By the end of 20 cycles of oil loading and squeezing, the caps had captured (1,105 g oil
in total) 395 g oil / g PO, while the pouches had captured (1,698 g oil in total) 606 g oil / g
EG+PO. With properly applied sewing of these pouches, we anticipate that the pouches could
have been used through far more cycles while retaining this rebounding propensity.
34
Figure 4-1. Water Tank 5-Second Drip Oil Capture Tests with Cap (1.3-1.5 g PO) versus Pouch (0.9-1.0 g PO + 0.3-0.4 g EG) in 200 mL Motor Oil, Fully Turbulent Water
Figure 4-2. Total Oil Capture Graph for Water Tank 5-Second Drip Tests with Cap (1.3-1.5 g PO) versus Pouch (0.9-1.0 g PO + 0.3-0.4 g EG) in 200 mL Motor Oil, Fully Turbulent Water
When we compare Figure 4-1 and 4-3, we see that about 1/3 of the captured oil drips by
the end of 40 seconds. There is also a similar trend in pooled averages, where they start going
down after cycle 9. Figure 4-4 illustrates that when comparing cycle 1 to cycles 2-8 total oil
Average Cap Pooled Average Pouch Pooled Average Cap
0
20
40
60
80
100
120
1 1 2-8 2-8 9-20 9-20
Ra
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Oil
Ca
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pe
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ass (
g/g
)
Cycle
EG Efficiency Cap Efficiency
Retained by EG in Pouch Retained by Cap in Pouch
35
capturing values to cycle 1 values, we note that the PO rebounded fully of its first-cycle oil
retention capacity, while the EG rebounded with 71% of its first-cycle oil retention capacity.
Figure 4-3. Water Tank 40-Second Drip Oil Capture Tests with Cap (1.3-1.5 g PO) versus Pouch (0.9-1.0 g PO + 0.3-0.4 g EG) in 200 mL Motor Oil, Fully Turbulent Water
Average Cap Pooled Average Pouch Pooled Average Cap
36
Figure 4-4. Total Oil Capture Graph for Water Tank 40-Second Drip Tests with Cap (1.3-1.5 g PO) versus Pouch (0.9-1.0 g PO + 0.3-0.4 g EG) in 200 mL Motor Oil, Fully Turbulent Water
Figure 4-5. Water Tank 5-Second Drip Oil Capture Tests with Cap (0.6-0.8 g PO) versus Pouch (0.6-0.9 g PO + 0.3-0.5 g EG) in 200 mL Motor Oil, Turbulent Water
* The first 3 sets for 5-second drip tests for pouches are calculated by considering the ratios of efficiencies in the 40-second drip tests.
CycleLSD 95% Pouch 1 Pouch 2Pouch 3 Cap 1 Cap 2Pouch Average Cap Average Pooled Average PouchPooled Average Cap
37
Figure 4-6. Total Oil Capture Graph for Water Tank 5-Second Drip Tests with Cap (0.6-0.8 g PO) versus Pouch (0.6-0.9 g PO + 0.3-0.5 g EG) in 200 mL Motor Oil, Turbulent Water
Comparing Figure 4-5 and 4-7 tells us that about 2/5 of the oily water continued dripping
by the end of 40 seconds. There is also a similar trend in pooled averages, PO's pooled average
seems to stagnate in Figure 4-7 and the same thing happens for EG in Figure 4-5. Figure 4-6
illustrates that when comparing cycle 1 to cycles 2-14 for total oil capturing values to cycle 1
values, we note that the PO rebounded with 85% of its first-cycle oil retention capacity, while the
EG rebounded with 56% of its first-cycle oil retention capacity but then recovered its capturing
ability for cycles 15-20.
0
20
40
60
80
100
120
140
160
1 1 2-14 2-14 15-20 15-20
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ass (
g/g
)
Cycle
EG Efficiency Cap Efficiency
Retained by EG in Pouch Retained by Cap in Pouch
38
Figure 4-7. Water Tank 40-Second Drip Oil Capture Tests with Cap (0.6-0.8 g PO) versus Pouch (0.6-0.9 g PO + 0.3-0.5 g EG) in 200 mL Motor Oil, Turbulent Water
Figure 4-8. Total Oil Capture Graph for Water Tank 40-Second Drip Tests with Cap (0.6-0.8 g PO) versus Pouch (0.6-0.9 g PO + 0.3-0.5 g EG) in 200 mL Motor Oil, Turbulent Water
CycleLSD 95% Pouch 1 Pouch 2Pouch 3 Cap 1 Cap 2Average Pouch Average Cap Pooled Average PouchPooled Average Cap
0
20
40
60
80
100
120
140
1 1 2-7 2-7 8-20 8-20
Ratio o
f N
ew
Oil
Captu
red p
er
Pocket
Mass (
g/g
)
Cycles
EG Efficiency Cap Efficiency
Retained by EG in Pouch Retained by Cap in Pouch
39
Gasoline and Diesel Fuel Mixture Tests
Figure 4-9. Water Tank 5-Second Drip Fuel Capture Tests with Cap (1.0-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.4 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Fully Turbulent Water
Figure 4-10. Total Fuel Capture Graph for Water Tank 5-Second Drip Tests with Cap (1.0-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.4 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Fully Turbulent Water
Average Cap Pooled Average Pouch Pooled Average Cap
0
10
20
30
40
50
60
70
1 1 2 2 3-7 3-7 8-20 8-20
Ra
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Ca
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ass (
g/g
)
Cycle
EG Efficiency Cap Efficiency
Retained by EG in Pouch Retained by Cap in Pouch
40
Figure 4-11. Water Tank 40-Second Drip Fuel Capture Tests with Cap (1.0-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.4 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Fully Turbulent Water
Figure 4-12. Total Fuel Capture Graph for Water Tank 40-Second Drip Tests with Cap (1.0-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.4 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Fully Turbulent Water
Average Cap Pooled Average Pouch Pooled Average Cap
0
10
20
30
40
50
1 1 2-6 2-6 7-20 7-20Ra
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Oil
So
rbe
d p
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Po
cke
t M
ass (
g/g
)
Cycle
EG Efficiency Cap Efficiency
Retained by EG in Pouch Retained by Cap in Pouch
41
Comparing Figure 4-9 and 4-11 tells us that about 1/3 of the oily water continued
dripping by the end of 40 seconds, also in both graphs it is seen that in later cycles the difference
between pooled averages shrank. There is also a similar trend in pooled averages, PO's and EG's
pooled averages seem to stagnate in both figures. In Figure 4-10, PO's rebound rate is 70% for the
second cycle with respect to the first cycle, and then it keeps its fuel capturing efficiency. Figure
4-12 illustrates that when comparing cycle 1 to cycles 2-6 for total fuel capturing values to cycle
1 values, we noted that the PO rebounded with 86% of its first-cycle oil retention capacity, while
the EG rebounded with 75% of its first-cycle oil retention capacity.
Figure 4-13. Water Tank 5-Second Drip Fuel Capture Tests with Cap (1.1-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.3 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Turbulent Water
Average Cap Pooled Average Pouch Pooled Average Cap
42
Figure 4-14. Total Fuel Capture Graph for Water Tank 5-Second Drip Tests with Cap (1.1-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.3 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Turbulent Water
Comparing Figure 4-13 and 4-15 tells us that about 1/3 of the oily water continued
dripping by the end of 40 seconds, also in both graphs it is seen that after the 3rd cycle difference
between pooled averages shrank. There is also a similar trend in pooled averages, PO's and EG's
pooled averages seem to stagnate in both figures. In Figure 4-14, PO's rebound rate is 75% for the
second cycle with respect to the first cycle, and then its fuel capturing efficiency stays constant.
Figure 4-14 and 4-16 show some increase in total fuel capture efficiency for cycle 2 with respect
to cycle 1.
0
10
20
30
40
50
60
70
80
1 1 2 2 3-20 3-20
Ra
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Ca
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g/g
)
Cycle
EG Efficiency Cap Efficiency
Retained by EG in Pouch Retained by Cap in Pouch
43
Figure 4-15. Water Tank 40-Second Drip Fuel Capture Tests with Cap (1.1-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.3 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Turbulent Water
Figure 4-16. Total Fuel Capture Graph for Water Tank 40-Second Drip Tests with Cap (1.1-1.3 g PO) versus Pouch (0.8-1.0 g PO + 0.3 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Turbulent Water
Average Cap Pooled Average Pouch Pooled Average Cap
0
10
20
30
40
50
60
70
1 1 2 2 3-20 3-20Ra
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Oil
So
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d p
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Po
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ass (
g/g
)
Cycle
EG Efficiency Cap Efficiency
Retained by EG in Pouch Retained by Cap in Pouch
44
Texas Crude Oil Tests
Figure 4-17. Water Tank 5-Second Drip Crude Oil Capture Tests with Cap (1.4 g PO) versus Pouch (1.0 g PO + 0.5 g EG) in 200 mL Texas Crude Oil, Fully Turbulent Water (Oil Only, Fixed According to Water Capturing Values from Cycles 21-25)
Figure 4-18. Total Crude Oil Capture Graph for Water Tank 5-Second Drip Tests with Cap (1.4 g PO) versus Pouch (1.0 g PO + 0.5 g EG) in 200 mL Texas Crude Oil, Fully Turbulent Water
CycleLSD 95% Pouch CapPouch w/o Water Cap w/o Water Pooled Average Pouch
Pooled Average Cap
0
10
20
30
40
50
60
70
80
1 1 2 2 3-13 3-13 14-20 14-20
Ra
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ass (
g/g
)
Cycle
EG Efficiency Cap Efficiency
Retained by EG in Pouch Retained by Cap in Pouch
45
Comparing Figure 4-17 and 4-19 tells us that about 1/3 of the oily water continued
dripping by the end of 40 seconds, also in both graphs it is seen that after the 3rd cycle there is no
true difference between pooled averages. There is also a similar trend in pooled averages, PO's
and EG's pooled averages seem to stagnate in both figures. In Figure 4-18, after cycle 2, for
pouch, it looks like total crude oil capture efficiency changes slowly after the first rebounding rate
of 51%.
Figure 4-19. Water Tank 40-Second Drip Crude Oil Capture Tests with Cap (1.4 g PO) versus Pouch (1.0 g PO + 0.5 g EG) in 200 mL Texas Crude Oil, Fully Turbulent Water (Oil Only, Fixed According to Water Capturing Values from Cycles 21-25)
Pouch w/o Water Cap w/o Water Pooled Average PouchPooled Average Cap
46
Figure 4-20. Total Crude Oil Capture Graph for Water Tank 5-Second Drip Tests with Cap (1.4 g PO) versus Pouch (1.0 g PO + 0.5 g EG) in 200 mL Texas Crude Oil, Fully Turbulent Water
Confined Packet Tests
Figure 4-21. Water Tank 5-Second Drip Fuel Capture Tests with Cap (1.0 g PO) versus Confined Pouch (0.5 g PO + 0.5 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Fully Turbulent Water
0
10
20
30
40
50
60
70
1 1 2-13 2-13 14-20 14-20
Ra
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Oil
Ca
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red
pe
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ocke
t M
ass (
g/g
)
Cycle
EG Efficiency Cap Efficiency
Retained by EG in Pouch Retained by Cap in Pouch
0
5
10
15
20
25
30
35
1 2 3 4 5
Ra
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g/g
)
CycleLSD 95% CapPouch Cap w/o WaterPouch w/o Water Pooled Average Pouch w/o WaterPooled Average Cap w/o Water
47
Figure 4-22. Water Tank 40-Second Drip Fuel Capture Tests with Cap (1.0 g PO) versus Confined Pouch (0.5 g PO + 0.5 g EG) in 200 mL 50-50 Gasoline and Diesel Fuel Mix, Fully Turbulent Water
Figure 4-22 and 4-22 show that in cycles 1, 4, and 5 Spun Polyolefin captured more water
than in cycles 2 and 3, whereas, it can be seen that the product captured less water in these tests.
This was due to the turbulence in the water tank where the samples got submerged into the water.
Previous graphs show a greater sorbance rate for product; therefore, it can be concluded that
when 0.50 g Spun Polyolefin and 0.50 g Exfoliated-Graphite-800 were used to make a pouch,
there was not enough space for the Exfoliated Graphite to expand.
0
5
10
15
20
25
1 2 3 4 5Ra
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red
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g/g
)
Cycle
LSD 95% Cap
Pouch Cap w/o Water
Pouch w/o Water Pooled Average Pouch w/o Water
Pooled Average Cap w/o Water
48
Figure 4-23. Water Tank 5-Second Drip Oil Capture Tests with Cap (1.0 g PO) versus Confined Pouch (0.5 g PO + 0.5 g EG) in 200 mL Motor Oil, Fully Turbulent Water
Figure 4-24. Water Tank 40-Second Drip Oil Capture Tests with Cap (1.0 g PO) versus Confined Pouch (0.5 g PO + 0.5 g EG) in 200 mL Motor Oil, Fully Turbulent Water
0
10
20
30
40
50
60
70
1 2 3 4 5
Ra
tio
of N
ew
Oil
Ca
ptu
red
pe
r P
ocke
t M
ass
(g/g
)
CycleLSD 95% CapPouch Cap w/o WaterPouch w/o Water Pooled Average Pouch w/o WaterPooled Average Cap w/o Water
0
10
20
30
40
50
1 2 3 4 5
Ra
tio
of N
ew
Oil
Ca
ptu
red
pe
r P
ocke
t M
ass (
g/g
)
Cycle
LSD 95% CapPouch Cap w/o WaterPouch w/o Water Pooled Average Pouch w/o WaterPooled Average Cap w/o Water
49
Without any surprises, pouch and cap samples worked more efficiently in motor oil than
they do in gasoline and diesel fuel mixture. In Table 4-1, it is seen that the pouch here did not
work as good as Spun Polyolefin alone due to limited space for expanding.
It was quite challenging separating water droplets from the oily water captured as a
matter of gasoline and diesel fuel mixture have a similar color and motor oil and water tend to
form a mousse when there is turbulence in the system.
Table 4-1. Water Capturing Percentage Values for Confined Pouch Tests
Hydrocarbon Drip Test Efficiency
(g Hydrocarbon / g Packet)
5-sec
Cap
5-sec
Pouch
40-sec
Cap
40-sec
Pouch
Gasoline and Diesel Fuel
Water and Oil 16.9 18.8 11.3 14.2
Oil Only 14.9 17.9 9.1 13.3
Water Content 13% 5% 24% 7%
Motor Oil
Water and Oil 41.1 38.9 22.8 27.3
Oil Only 40.8 38.6 22.6 27.2
Water Content 1% 1% 1% 1%
The table above shows that water content was higher in gasoline and diesel fuel mixture
tests than it was in motor oil tests. Also it should be noted that the product captured less water on
average than by using Spun Polyolefin alone. Additionally, the table below at the end of the 40-
second dripping, the product sorbs less water.
Table 4-2. Water Capturing Percentage Values for Texas Crude Oil Tests - Cycles 21-25
Hydrocarbon Drip Test Efficiency
(g Crude Oil / g Packet)
5-sec
Cap
5-sec
Pouch
40-sec
Cap
40-sec
Pouch
Texas Crude Oil
Water and Oil 30.3 21.2 20.2 13.8
Oil Only 29.2 20.3 18.2 12.7
Water Content 4% 5% 11% 8%
Table 4-3. The Least Significant Difference (LSD) Comparison Chart
Hydrocarbon
Average Efficiency After 5 Second Dripping Average Efficiency After 40 Second Dripping
Cycl
es
Exam
ined
Pou
ch
Cap
Dif
fere
nce
LSD Comparing
Difference to
LSD Cycl
es
Exam
ined
Pou
ch
Cap
Dif
fere
nce
LSD Comparing
Difference
to LSD 95
%
98
%
99.5
%
95
%
98
%
99.5
%
Motor Oil* Turbulent
2-14 48.3 38.4 10.0 2.5 3.1 3.8 > LSD all 2-7 28.7 21.4 7.2 2.2 2.7 3.5 > LSD all
15-20 50.0 33.8 16.2 2.8 3.4 4.5 > LSD all 8-20 24.3 19.6 4.8 1.4 1.7 2.1 > LSD all
* The first 3 sets for motor oil in turbulent conditions for 5-second drip tests are calculated by considering the ratios of efficiencies in the 40-second drip tests. ** Fixed According to Water Capturing Values from Cycles 21-25
Table 4-4. Average Oil Capturing and Average Efficiency for the Whole Test Set
Hydrocarbon
Drip
Time
(sec)
Pouch (EG+PO) Cap Only (PO) Number
of Cycles
(10 min
Each)
Condition Oil
Captured
(g)
Average
Efficiency
(g/g)
Oil
capturing
(g)
Average
Efficiency
(g/g)
Motor Oil* 5 1,006 51.1 532 37.7
20 Turbulent 40 571 28.5 305 15.3
Gasoline & Diesel
5 437 21.9 311 15.6 20 Turbulent
40 261 13.1 198 9.9
Motor Oil 5 849 42.5 553 27.6
20 Fully
Turbulent 40 639 31.9 446 22.3
Gasoline & Diesel
5 376 18.8 271 13.6 20
Fully Turbulent 40 278 13.9 198 9.9
Texas Crude Oil**
5 954 35.1 922 33.7 20
Fully Turbulent 40 665 24.3 686 24.9
* The first 3 sets for motor oil in turbulent conditions for 5-second drip tests are calculated by considering the ratios of efficiencies in the 40-second drip tests. ** First 20 cycles are taken into consideration for comparison reasons and due to staples in the pouches falling after this time.
In the table above, average oil capturing is represented, by total weight and efficiency as
oil captured per pouch mass. Mass of oil captured is given as the total amount of oil captured
divided by the number of pouches used for those sets of experiments.
Figure 4-25. Tests for Determining Water Capturing Percentages
* Left: Texas Crude Oil; Right: Motor Oil ** Lower Dish: 40-second drip tests; Upper Dish: Oil and Water Claimed After Squeezing
52
Steps That Led to Product Design
Before deciding on the envelope material, how to use Exfoliated Graphite, and which
Exfoliated Graphite to use, the steps mentioned in the following were executed.
Experiments with polyolefin were done. Polyolefin was tried in oil products. Other
experiments were executed to see how polyolefin behaved with Exfoliated-Graphite-600. Another
test was conducted with polyolefin and Exfoliated-Graphite-600 in a fiberglass pouch.
Later, Exfoliated-Graphite-600 and Exfoliated-Graphite-800 were tested in various ways.
These include tests with motor oil, gasoline and diesel fuel mixture, three fuel mixture, Texas
crude oil, Pennsylvania crude oil, sea water, fresh water, calm water with a light surface agitation
(1-pump tests in water tank), sea water mousse, and fresh water mousse.
Also, the application of Exfoliated Graphite was considered and envelope materials were
put under tests to determine the formation of the pouch and then the product. Envelope materials
were tried under different conditions to determine the best companion for Exfoliated Graphite.
Experimental data showed that bouffant cap (made from Spun Polyolefin) was the best choice
among tried materials.
Table 4-5. Exfoliated Graphite Hydrocarbon Capturing Tests E
G F
orm
ati
on
Tem
per
atu
re
(ºC
)
Coll
ecti
on
Pro
toco
l
Wate
r V
olu
me
(mL
)
Oil
Con
tact
Tim
e (m
in)
Hyd
roca
rbon
Typ
e
Hyd
roca
rbon
Volu
me
(mL
)
En
vel
op
e
Mate
rial
En
vel
op
e
Mass
Ran
ge
(g)
EG
Mass
Ran
ge
(g)
Aver
age
Oil
y
Wate
r
Cap
ture
d (
g)
Aver
age
Cap
turi
ng
Eff
icie
ncy
(g/g
)
Sta
nd
ard
Dev
iati
on
Nu
mb
er o
f
Cycl
es
Nu
mb
er o
f
Pu
mp
s
600 Grid Filter Tap 100 1 Gasoline & Diesel
10 None n/a 0.04-0.09
2.49 36.3 4.5 0 0
600 Grid Filter Tap 100 5 Gasoline & Diesel
20 None n/a 0.05 1.52 30.2 1.7 0 0
600 Grid Filter Tap 100 2 Motor Oil 10 None n/a 0.10-0.13
4.95 45.1 8.5 0 0
600 Grid Filter Tap 100 10 Motor Oil 20 None n/a 0.05 2.30 46.0 3.5 0 0
600 Spoon Pick
Tap 200 3 Motor Oil 20 Fiberglass 2.34 0.17 17.59 7.01 n/a 0 0
600 Spoon Pick
Tap 200 3 Motor Oil 20 Fiberglass 1.58 0.09 8.70 5.21 n/a 0 0
Polyolefin was considered as an aiding material to Exfoliated Graphite. The product of
polyolefin did not prove to be beneficial or efficient in this study. The following figure shows the
results obtained from related experiments.
Figure 4-26. Polyolefin Oil Capturing Tests for 2 Hours in 10 mL of Motor Oil on 100 mL of Water
When polyolefin was tested in 20 mL of motor oil, at the end of 24 hours, it was seen that
it captured 3.4 times of its weight and when it was mixed with Exfoliated-Graphite-600 the oil
capturing rate of mixture happened at 33.5 times of its mass.
The pouches consisting of Exfoliated-Graphite-600 and polyolefin in a fiberglass
envelope were tested and 1:4.7 oil capturing ratio was retrieved as an average.
0.00
0.03
0.06
0.09
0.12
0.15
0.18
0.00 0.03 0.06 0.09 0.12 0.15
Moto
r O
il S
orb
ed (
g)
Polyolefin (g)
60
Figure 4-27. Polyolefin Oil capturing Tests in 10 mL of 50-50 Gasoline and Diesel Fuel Mixture on 100 mL of Water
Exfoliated Graphite, without polyolefin, was found to be working better in oil capturing
tests. Therefore, further tests were run by using Exfoliated Graphite only.
Experiments with Envelope Materials without Exfoliated Graphite
Using Exfoliated Graphite on its own in a real life crisis is extremely difficult since the
accidents happen in harsh weather and sea conditions where wind speeds are high. The density of
Exfoliated Graphite changes according to its preparation methods and forming temperature. In
their study Toyoda and Inagaki give the densities as 6 and 10 kg/m3, and total pore volumes as
2.3x10-2 and 2.0x10-2 m3/kg (Heavy oil capturing using Exfoliated Graphite: New application of
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.00 0.05 0.10 0.15 0.20 0.25
Oil
Sorb
ed (
g)
Polyolefin (g)
Polyolefin Sorption Test in 50-50 Gasoline and Diesel Fuel Mixture
20 Minutes 24 Hours Linear (20 Minutes) Linear (24 Hours)
61
Exfoliated Graphite to protect heavy oil pollution). As Exfoliated Graphite is a very light
substance, controlling it is virtually impossible; therefore, it is necessary to put it in an
“envelope” and preparing a “pouch” before applying it to the oil spill.
Another goal of the project is finding a commercially available material to be used as an
envelope for Exfoliated Graphite. In this way, the envelope will not be expensive and readily
available for further use. After a market research these materials were used in the experiments:
fiberglass, bouffant cap, ribbon, tulle, and silk screen. Other mesh products such as grape nets and
fruit nets were found to be too wide to keep Exfoliated Graphite inside; therefore, they were
abandoned.
Envelope materials were tested for the hydrophilic property – since this is not desired.
Also, these materials were tested for their oil sorbance capacity in motor oil, and 50-50 gasoline
and diesel fuel mixture; these following results were found.
Table 4-7. Water and Oil Product Oil and Water Capturing Test Results Run for 10 Minutes for Envelope Materials on 100 mL of Water Only for Water Capturing Test and 100 mL of Water and 10 mL of Oil Product in Oil Capturing Tests
Figure 4-28. Pouch Materials: a) Tulle b) Fiberglass c) Silk Screen d) Ribbon
Spun Polyolefin was also tried in another way; first, it was dipped in water and then
applied to gasoline and diesel fuel mixture.
Tulle pouch generated problems since the mesh size was too big for Exfoliated Graphite
as it was falling through. Ribbon pouch was easy to produce and the mesh radius was small
enough to keep the Exfoliated Graphite inside and the average oil capturing rate stood at 1:11.3,
which made it second to Spun Polyolefin pouch. The Spun Polyolefin’s material is sturdy, even if
someone pulls it, it does not break. The oil capturing rates were the best with Spun Polyolefin
tests.
Spun Polyolefin stood out as the best envelope material used in this project.
63
Figure 4-29. Spun Polyolefin Oil capturing Test for 5 Minutes in 20 mL of 50-50 Gasoline and Diesel Fuel Mixture on 100 mL of Water
Figure 4-30. Spun Polyolefin Oil capturing Test for 5 Minutes in 20 mL of Motor Oil on 100 mL of Water
0
5
10
15
20
25
0.00 0.02 0.04 0.06 0.08 0.10 0.12
Gas a
nd D
iesel F
uel M
ixtu
re S
orb
ed (
g)
Cap (g)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0.00 0.02 0.04 0.06 0.08 0.10
Moto
r O
il S
orb
ed (
g)
Cap (g)
64
Experiments with Exfoliated-Graphite-600
Before passing to the envelopes, Exfoliated Graphite was tried on its own. First,
Exfoliated-Graphite-600 was tried in a 50-50 gasoline and diesel fuel mixture. On average,
Exfoliated Graphite captured 36.3 times of its mass.
Figure 4-31. Spun Polyolefin Pouch Oil Capturing Tests Run for 3 Minutes in 10 mL of 50-50 Gasoline and Diesel Fuel Mixture on 100 mL of Water
0
1
2
3
4
5
6
0.00 0.03 0.06 0.09 0.12
Gasolin
e a
nd D
iesel F
uel M
ixtu
re S
orb
ed (
g)
Bouffant Cap and Exfoliated-Graphite-600 Pouch (g)
65
Figure 4-32. Spun Polyolefin (Previously Dipped in Soapy Water) Pouch Oil Capturing Test for 3 Minutes in 40 mL of 50-50 Gasoline and Diesel Fuel Mixture on 100 mL of Water
For the tests in motor oil, Exfoliated-Graphite-600 showed a oil capturing efficiency of
46 times of its mass in 10 minutes (Table 4-5).
Experiments with Exfoliated-Graphite-800
After many trial-and-error sets, Exfoliated-Graphite-600 was abandoned and
Exfoliated-Graphite-800 was used in the new sets. The reason behind was to gain
experience and make use of the available materials in the best way.
0
1
2
3
4
5
6
0.00 0.02 0.04 0.06 0.08 0.10
Gasolin
e a
nd D
iesel F
uel M
ixtu
re S
orb
ed (
g)
Bouffant Cap (Previously Dipped in Soapy Water) and Exfoliated-Graphite-600 Pouch (g)
66
After these sets of experiments, an effort of standardizing was undertaken. In order to
compare results, 0.05 g of Exfoliated-Graphite-800 was used in different sets with different
variables.
Exfoliated-Graphite-800 was applied for 10 minutes to motor oil. The highest oil
capturing rate happened in 7 mL of motor oil and sea water tests gave a higher oil capturing rate
(Table 4-5).
For the next set, 20 mL of motor oil was used, and in each set 0.05 g of Exfoliated-
Graphite-800 was applied. The experiments show how Exfoliated-Graphite-800 acts for different
time periods. The highest oil capturing rate occurred at 12-hour tests with 43.5 times the mass of
Exfoliated-Graphite-800.
Another trial was completed by mixing motor oil and gasoline-and-diesel-mixture in
equal volumes. Exfoliated-Graphite-800 was applied on 50-50 gasoline and diesel fuel mixture on
water, grid filter protocol was used to get the results. Different durations and different volumes of
the fuel mixture were tried for these sets of experiments.
Figure 4-33. Exfoliated-Graphite-800 Only Oil Capturing Tests in 20 mL of 50-50 Gasoline and Diesel Fuel Mixture and Motor Oil on 100 mL of Water
0
10
20
30
40
50
60
70
80
1 10 100 1000
Oil
So
rptio
n p
er
Exfo
liate
d G
rap
hite
(g
/g)
Time (min)
Motor Oil Gas & Diesel
67
To summarize, Exfoliated-Graphite-800 shows the average performances for these
experiments with 20 mL of 50-50 gasoline and diesel fuel mixture on 100 mL of water for
different times as it is shown in the previous table. For waiting time periods of 1 to 30 minutes,
the average oil capturing is 44.9, and the oil capturing performance starts increasing at the 60-
minute run time and increasing even further at the 720-minute run.
In the following figure, it can be seen that average oil capturing increases with the
increase in gasoline and diesel fuel mixture volume. From the 2-mL test to the 40-mL test, there
is a 1/3 increment in the oil capturing efficiency.
Figure 4-34. Exfoliated-Graphite-800 Only Oil capturing Test in 50-50 Gasoline and Diesel Fuel Mixture on 100 mL of Water for 5 Minutes by Grid Filter Protocol
0
5
10
15
20
25
30
35
40
45
50
0 5 10 15 20 25 30 35 40 45
Gas o
line a
nd D
iesel F
uel M
ix S
orp
tion
per
Exfo
liate
d G
raphite M
ass (
g/g
)
Gasoline and Diesel Fuel Mixture (mL)
68
Application of Exfoliated-Graphite-800 in Spun Polyolefin Pouch
Since the pouches were prepared by attaching the ends of the Spun Polyolefin around
Exfoliated Graphite, during some oil recovery tests they were not usable for the next set of
experiments as they were damaged. In a real product, stitches will take the place of staples hence
the product is believed to be stronger.
In Table 4-5 it is shown that the pouch's oil capturing performance was the highest in
motor oil standing at 38.2 times if its mass. For Pennsylvania crude oil the oil capturing
efficiency was 15.4 and for Texas crude oil it was 20.2 of the pouch's mass. Next, when the
pouch was used in the water tank in motor oil during a calm water with a light surface agitation
test (1-pump test), the oil capturing capacity stood at 34.2 times the mass of the pouch.
Chapter 5
Conclusions
Exfoliated Graphite has been used to capture spilled oil from the surface of water and
when it was enveloped by Spun Polyolefin. Spun Polyolefin helped Exfoliated Graphite to be
used for a specific location, securing it inside a pouch, and more importantly, this material also
proved itself efficient in oil spill cleaning up (This product has a higher sorbance performance in
motor oil then in gasoline and diesel fuel mixture). The author will be delighted if this product
can be commercialized and made available for people helping the environment.
The tests that compared Exfoliated-Graphite-600 and Exfoliated-Graphite-800 showed
that the higher preparation temperature gave Exfoliated Graphite more efficient hydrocarbon
capturing rates and more expanding made it possible to have a higher surface area and sorb more
hydrocarbons.
Water capturing tests were conducted for the product inside of confined pouches (1-gram
pouch tests). Water content was higher in gasoline and diesel fuel mixture tests than it was in
motor oil tests. Also it should be noted that the product captured less water on average than by
using Spun Polyolefin alone. In Texas crude oil tests 40-second dripping readings showed that the
product sorbs less water.
It was observed that Exfoliated Graphite inside the pouch needs space to expand in order
to reach its potential. However, when equal masses of Spun Polyolefin and Exfoliated Graphite
were used, the pouch's hydrocarbon capturing efficiency was less than Spun Polyolefin alone.
Furthermore, it is beneficial to have the pouch unfolded for it to work more efficiently, since
Spun Polyolefin in it works in a less efficient way when it is folded. Pouches gave the highest
hydrocarbon capturing efficiency in motor oil. Their performance is approximately 1/3 better than
70
their performance in gasoline and diesel fuel mixture. When there is Exfoliated Graphite in the
packet, it tends to capture less water than when Spun Polyolefin is used alone. The product floats
on water and is easy to collect back. Captured hydrocarbon can easily be gained back just by
squeezing the packet. The first cycle gives the least amount of hydrocarbon back (it does not get
less than 80%), later on, reclamation of new hydrocarbon captured gets to around 100%.
71
Chapter 6
Future Work
Exfoliated Graphite takes a lot of space and therefore great effort to carry to where it is
needed. Also, storage is another issue. It might be useful to develop a process of preparing EG-
PO pouches in situ for real life applications. Potential users of these pouches could be the harbor
management officials who can have the graphite exfoliated and used after an oil spill in their area.
The author recommends for future researchers to look into this aspect.
All of the experiments were conducted in the lab environment, at room temperature,
without being exposed to sunlight or other outside effects. Effects of the temperature of water and
petroleum products can be investigated. Water tank experiments simulated wavy and turbulent
conditions, however, those tests did not employ windy conditions. If possible, a real life test in an
actual oil spill area would give a bigger insight on the usefulness of EG-PO pouches.
Apart from 10W-40 motor oil, gasoline, diesel fuel, Texas crude oil and Pennsylvania
crude oil, more pollutants can be used in experiments. The pouches already work efficiently in
water tank oil capturing tests and it would be useful to see how the product would work with
different pollutants.
Inspecting the mass ratio of Exfoliated Graphite to Spun Polyolefin in order to find the
optimum amounts (if any) to be used together might be considered.
References
1. A Reference Guide To Polyolefins, Engineered Resins, and Fluorocarbons,
http://www.polyprocessing.com/pdf/technical/tdpolyolefins.pdf, retrieved on 01/21/2012.
2. ASTM D-1141 Standard Practice for the Preparation of Substitute Ocean Water.
3. ASTM D-95 Standard Test Method for Water in Petroleum Products and Bituminous
Materials by Distillation.
4. ASTM F2534-12, Standard for Visually Estimating Oil Spill Thickness on Water.
5. Clean up of diesel fuel spill in Ventura Harbor continues, United States Coast Guard News