Rice husk and Raw Cotton as alternative oil absorbents
Gallega, R. & Rubis, J.
Grade 10-A
De La Salle University Integrated School
A.Y. 2013-2014
1
Introduction
Annually in the United States, about 100 million gallons of crude oil is spilled in bodies
of water often due to oil tanker leakages. Such an amount can negatively affect wildlife,
communities and the like. In this study, the group will conduct a research that can discover more
viable, natural and practical alternatives in absorbing spilled oil using the materials rice husks
and raw cotton. These two are selected due to the fact that these can be easily accessed by
communities all over the Philippines and that one of these are often wasted, which can also
potentially lead to pollution in our natural environment. The researchers will also determine if
these substitutes are able to absorb more oil than commercial absorbents such as polypropylene.
Hence, developing the research question “Are rice husks and raw cotton viable and natural
alternatives to commercial absorbents, in terms of absorption properties and eco-friendliness?”
The group hypothesizes that there is a difference between the amount of oil absorbed by the
alternatives and the commercial absorbents. However, the group’s null hypothesis states that
despite the material, the amount of oil absorbed remains the same. The limitations of the study
are as follows: these alternatives will be experimented on only two types of oil: diesel and
gasoline, and their absorption will only take place in freshwater. Also, their results will only be
compared to that of only one commercial absorbent, which is polypropylene.
Review of Related Literature
The Philippines is a country with a significant abundance of rice and cotton, which are
used by multiple industries in the nation. However, it is also a country that is currently a victim
of water pollution but more specifically, oil spills. Such disasters can negatively affect both
human communities and marine ecosystems through environmental and economic means. The
researchers will compare the two natural materials with polypropylene (the commercial oil
absorbent most commonly used during oil spills) by their sorption capabilities. The purpose of
this Review of Related Literature is to show previous findings relating to the oil absorbents
mentioned and to take them into consideration in this research.
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Rice Husk
Rice husk is widely available in the Philippines, annually generating over 3.1 million
tons. It is mainly comprised of Opaline Silica and Lignin to safeguard the seed during the
budding season. Most of the husk after milling is either burnt (which can release greenhouse
gases in the atmosphere) or dumped as waste in open fields, otherwise it is sometimes used as
fuel for boilers, pest control agents and bulking agents for composting of animal manure.
(Chapter 2 Rice Husk – A Review, 2013). The potential of rice husk for oil adsorption was
studied due to its special cellular structure. These properties of rice husk contribute to its being
both oleophilic and hydrophobic in nature, with an oil adsorption capacity of 74.66g based on a
previous research about rice husks (Huang et al., 2005).
Leftover rice husk from the oil spill will not endanger any species or the marine
ecosystem due to its being a natural grain by-product. It is also commonly used as fish feed and
are eaten by the fish eagerly. Most of the husk is not digested, but is spread around the water by
the fish, further nourishing reef systems and other marine organisms (Chapter 2 Rice Husk – A
Review, 2013).
Raw Cotton
Raw cotton is another resource that is also widely available in the Philippines, producing
over 2000 metric tonnes per annum. This kind of cotton floats on water and is both hydrophobic
and oleophilic in nature. Due to these properties, raw cotton has the capability to absorb high
volumes of oil in water, with a 30.5g/g oil absorption capacity (Singh et al., 2013). In contrast to
synthetic sorbents, raw cotton both has flotation capabilities and biodegradability, making it an
environmentally friendly absorbent for cleaning oil spills (Sinpetru, 2013). Additionally for the
environment, raw cotton is primarily made of cellulose which is a bond consisting of linked
sugars. All marine vertebrates (most especially, fish) cannot naturally digest cellulose through
their digestive system. Instead, cellulase is needed to break down the tight bonds of cellulose
which can only be produced through the help of foreign intestinal bacteria. As a result, the
ingested raw cotton will pass harmlessly through the animals’ body as waste.
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Polypropylene
Polypropylene is a petroleum based oil absorbent that is used by multiple oil spill
response industries due to its oleophilic and hydrophobic properties. It is capable of 16.60mL per
gram used, and is also a component used in commercial equipment such as booms, sweeps and
pads (UCSB ScienceLine, N.A.). As for its effect on the environment, polypropylene is
recyclable and is non-hazardous to ecological habitats. But it can potentially release CO2 gases
in the atmosphere if burned. Furthermore, polypropylene is expensive compared to the natural oil
absorbents with a minimum price of $4.00 per lb.
Overall, raw cotton and rice husk are potential natural absorbents because of their high
sorption capacity, great availability, cost-effectiveness and eco-friendliness. As stated before,
these properties will be compared with those of polypropylene in order to determine if they are
effective enough to be alternatives.
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Methodology
Materials
Material
Quantity
Polypropylene
660 g. or 1.5 lbs.
Additional Information

in rolls or pads.

Rice Husk
Raw Cotton
660 g. or 1.5 lbs.
660 g. or 1.5 lbs.
Type of Rice:
Oryza Sativa

Bought in sacks.

Type of Cotton:
Gossypium Hirsutum

Basin
Most preferably bought
Must be in a size that
can fit up to 5 liters of
6 pcs.
liquid.

Plastic.
Plastic Nets
18 pcs.

Disposable.
Weighing Scale
1 pc.

Can be analog or digital.
Water
54 L.

Most preferably tap
water.

Gasoline
9 L.
gas station.

Diesel
9 L.
Can be bought from any
Can be bought from any
gas station.
Table 1
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Procedure
Part One: Apparatus Setup
1. Collect 110 g. / 0.25 lb. of each of the three (3) absorbents and wrap each of them using a
plastic net.
2. Add three (3) liters of water to each of the three (3) basins, and then pour one (1) liter of
gasoline in each of them.
3. Repeat steps 1 and 2, basins. There should be 3 basins of diesel, 3 basins of gasoline and
2 bags of each absorbent.
Part Two: Absorption Rate and Capacity Test
4. The first set of the three (3) different kinds of absorbent bags will be released into their
respective gasoline-filled basins for a total duration of one (1) hour.
5. Every fifteen (15) minutes, each bag will be weighed to determine the amount of gasoline
absorbed.
6. After the entire time period, measure the final weight of the bags then subtract it to their
original weight to find the total amount of gasoline absorbed. Repeat steps 4 and 5, but
this time release the second set bags into the basins filled with diesel.
7. After the results have been recorded, dispose the soaked absorbents and clean the basins.
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Data Analysis
Absorption Capacity
Absorption capacity is the amount of liquid a solid is able to absorb. To compute for the
absorption capacity of the alternative absorbents and control, the researchers will weigh the
materials before they release it into the suspension composed of the specified oil and fresh water.
After the one (1) hour time period, the researchers will then acquire the material then weigh it
again. The researchers will subtract the original weight of the material to its new weight then
divide the result to the amount in grams of the absorbent used, thus acquiring the absorption
capacity of the material per given gram. This test will be attempted three (3) times, meaning that
the three (3) absorption capacities of each material will be averaged in order to determine their
mean result. This is to have accuracy in the results of the experiments conducted.
Absorption Rate
To compute for the absorption rate of the alternative absorbents and control, the
researchers will acquire the material from the oil/fresh water suspension every fifteen (15)
minutes from release in a time period of one (1) hour. The material will be weighed and the
original weight will be subtracted from the new weight, thus getting the amount of absorbed oil.
This will be done a total of four (4) times. The four (4) results acquired will be added then
divided by four (4) in order to get the average amount of oil absorbed by the material per fifteen
(15) minutes, which will be further simplified to find the absorption rate per minute. However,
the test will be conducted up to three attempts. Each average absorption rate from each attempt
will be further averaged in order to determine the mean absorption rate.
The results from both tests will be displayed in Table 2.1. Furthermore, there will be a
total of six (6) of these tables as the tests will be attempted three (3) times per type of oil. Each
interval depicts the amount of oil gained after fifteen (15) minutes.
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1st Interval
2nd
3rd
Interval
Interval
4th Interval
Absorption
Total Amt. of
Rate
Absorbed Oil
(/min.)
(g.)
Raw Cotton
Rice Husk
Polypropylene
Table 2.1
Table 2.2 will show the final and mean absorption rate and capacity based on the three
results from Table 2.1. There will be again two (2) of these tables as there are two types of oil
tested.
Mean Absorption Rate (g/min.)
Mean Absorption Capacity (g/g.)
Raw Cotton
Rice Husk
Polypropylene
Table 2.2
Social Impact Analysis
The target market for these natural absorbents will be communities that live near bodies
of freshwater and agricultural industries that specialize in cotton or rice. With these products, the
mentioned groups will be able to hastily respond to oil spills due to the cost-effectiveness and
quick accessibility of the absorbents. Also, these can be sold to markets by the industries in order
to gain additional income apart from selling them in their usual functions (as edible rice, cotton
buds etc.). These are the expected results that will be looked forward to, once the products are
introduced to the communities. However, there may be some negative consequences of using
these absorbents towards other particular groups. Firstly, plastic manufacturing companies might
be affected, as the consumers will now be using the natural alternatives instead of their
polypropylene. This can lead them to a decrease in sales, which means that their business
revenues might slightly decline.
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Figure 1 below will be used to survey professionals specializing in oil absorption or
natural absorbents, oil response team members, civilians living by freshwater and victims who
were subjected to oil spills. This is because these are the people who are either knowledgeable in
this research topic or once experienced water pollution in their area due to an incident of spilt oil.
Figure 1
The feedback from the people being surveyed will be either displayed in a pie or bar
graph, showing their favorability of each absorbent. Their opinions of them will be taken into
consideration as well.
Financial Analysis
After conducting the research, two (2) effective and environmentally friendly end
products will be available for sale: a net bag containing raw cotton and another one containing
rice husk. The target beneficiaries who might develop interest in these will most likely be past
victims of oil spills, communities living by freshwater areas, oil spill response organizations and
oil transportation industries.
The products will be marketed through the use of leaflets and brochures. These will be
distributed to the offices of the barangays that reside near freshwater bodies and to oil-related
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organization facilities. This can be done by mail or simply by meeting with their representatives
in person. The leaflets and brochures will contain all essential information the target consumers
need to know about the products, such as price and method of production.
Table 3.1 depicts all the expenses that will cover the entire research including the prices
of the three (3) absorbents, their quantities and suppliers.
Quantity
Retail Price
Total Cost
No. of Units
Raw Cotton
660g. (1.5lbs.)
Php36/lb.
Php54
6
Rice Husk
660g. (1.5lbs.)
Polypropylene
660g. (1.5lbs.)
Fresh Water
3 L.
Basin
6 pcs.
Php100/pc.
Php600
(Mentioned)
Weighing Scale
1 pc.
Php200/pc.
Php200
(Mentioned)
Diesel
1 L.
Php45/L.
Php405
9
Gasoline
1 L.
Php50/L.
Php450
9
Plastic Nets
3 pcs.
Php50/pc.
Php150
(Mentioned)
6
Php150/lb.
Php225
6
18
Total Expenses:
Php2,084
Table 3.1
Due to these costs, the group will request from the educational institution a budget of
Php2500 and a free provision of scientific laboratory equipment for the research. Table 3.2 will
display how the products will be sold and the amount of income gained from them. The products
can either be sold in individual units or in packages (each containing eight). If all twenty (20)
units are sold, then the net income gained will be approximately Php1916.
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Raw Cotton Net
Bag
Rice Husk Net
Bag
Quantity
Retail Price
No. of units
Income
1kg
Php200/kg
10
Php2,000
1kg
Php200/kg
10
Php2,000
Table 3.2
Work Plan of Study
The execution of the entire research will last ten (10) weeks or about two (2) months,
from July until August, 2014. If there are any interruptions to the schedule in Table 4 such as
holidays and/or calamities, the researchers will continue the unfinished work as soon as possible.
The group as well requests for the research to be conducted inside a controlled environment such
as the school laboratory. Otherwise, it will be done instead in one of the group members’ homes.
First Week
Purchase of materials from suppliers
Second Week
Absorption Rate and Capacity Test (Attempt 1)
Third Week
Absorption Rate and Capacity Test (Attempt 2)
Fourth Week
Absorption Rate and Capacity Test (Attempt 3)
Fifth to Sixth
Analysis and Formulation of Data
Seventh to Eighth Week
Distribution of Questionnaires
Ninth Week
Tenth Week and Onwards
Formulation of conclusion based on results from
fifth and sixth week.
Preparation for publication
Table 4
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Literature Cited

Chapter 2 Rice Husk – A Review. (n/d). Properties of Rice Husk. Retrieved November
25, 2013, from
http://shodhganga.inflibnet.ac.in/bitstream/10603/5599/10/10_chapter%202.pdf

Y., Viola, D., Belinda, J., and Tony, S.(2005) Rice husks and oil pollution. In Section
1.3: Some methods of solving the oil pollution. Retrieved November 28, 2013, From
http://rudar.ruc.dk/bitstream/1800/2281/1/Rice%20husks%20and%20oil%20pollution.pdf

Singh, V., Kendall, R.J., Hake, K., Ramkumar, S.(2013). Crude Oil Sorption by Raw
Cotton. Retrieved November 28, 2013, From
www.pubs.acs.org/doi/pdf/10.1021.ie4005942.

Sinpetru, L. (May 16, 2013). Raw Cotton Might Help Clean Up Oil Spills.
Softpedia.com, Retrieved November 28, 2013, From
http://news.softpedia.com/news/Raw-Cotton-Might-Help-Clean-Up-Oil-Spills353862.shtml.

UCSB ScienceLine. (n.d.). Retrieved November 28, 2013. From
http://scienceline.ucsb.edu/getkey.php?key=2347
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