Methodology :p

CHAPTER II

METHODOLOGY

Chitin generated from the exoskeleton of crabs is the adsorbent that will be used for this study. The exoskeleton of crabs will be taken from a local market. Chitin will be obtained in powdered form. Chitosan will be prepared from chitin by deacetylating 50-g amounts of chitin in 1-L volumes of NaOH at 100˚ C for 5 hours. Temperature, time, and concentration of alkali will be kept constant throughout the experiments. The deacetylated chitin will be then left to dry in an oven at 70˚ C and then stored in sealed container.

As for the adsorbates, lead and arsenic will be used. Test solutions will be prepared from laboratory made stock solutions. The concentration of the metal before and after the chitin is added will be measured by using an atomic absorption spectrophotometer when available. The change in the concentration of the metal and the rate of adsorption will be measured or obtained.

There will be three setups for each trial. The first setup will be the test solution with lead as an adsorbent. The second setup will be the test solution with arsenic as an adsorbent. Lastly, the third setup will be the controlled setup where no test solutions will be used. All setups contain constant amounts of the adsorbent, chitin. All three setups will be kept in a room with constant temperature.

The experiment will be done in the Department of Science and Technology in Trece Martires, Cavite City or if possible in other laboratories of colleges. It is more appropriate to use test solutions because a naturally occurring source for both metals, lead and arsenic, will be difficult to control especially when it comes to the concentrations of the heavy metals.

Test solutions will be prepared from laboratory made stock solutions.

*FLOW CHART HERE* Ü

In this flow chart, the steps are well organized. In gathering the materials, the chitin will be obtained in powdered form through physical pretreatment comprising drying, grinding and sieving which is attractive for the recovery of 50% of protein as a dry powder. Pretreatment of shells by shearing in acidified water results in the removal of up to 60% of the protein and a reduction of their mineral content without a decrease in the chitin yield.

The test solutions will be lead and arsenic which will be obtained in laboratories. The three setups will be subjected to constant temperature with similar amounts of adsorbents and adsorbates in each setup.

The analysis of the results will show whether natural polymers such as chitin are suitable adsorbents for heavy metals like lead and arsenic. The results will also show the rates of adsorption for each of the two test adsorbates.

Review of Related Literature :)

Review of Related Literature

Past researches involved the use of hydro-carbon degrading bacteria in cleaning Manila Bay. Now, it is discovered that not all heavy metals can be readily removed from a contaminated source. However, there are instances when the heavy metals bind to a source and this source helps in removing the concentration of heavy metals in a contaminated area.

In order for the substances to successfully bind with the heavy metals, certain conditions are necessary. The right temperature, nutrients (fertilizers), and amount of oxygen must be present in the sol and ground water. These conditions allow a faster rate of adsorption or binding with the heavy metals.

Bioremediation is favorable because it takes advantage of naturally occurring processes. If the right conditions exist, groundwater or even soil can be treated without having to dig or pump it all up. Another advantage of using bioremediation is that it makes the workers or any other people avoid contact with a contaminated site so there is little risk of its harmful effects. Often bioremediation does not require much equipment or labor as most other methods. Therefore, it is usually cheaper. Bioremediation has successfully cleaned up many polluted sites and is being used at 50 superficial sites across the country.

Aside from using microorganisms in treating waste waters, natural biopolymers are industrially attractive because of their capability of lowering transition metal-ion concentration to parts per billion concentrations. Natural materials that are available in large quantities or certain waste from agricultural operations may have potential to be used as low cost adsorbents, as they present unused resources, widely available and are environmentally friendly.

Alternatively, it has been suggested that some natural polymers may be used for waste water treatment application. Most of these studies investigated possible uses for such adsorbents to remove heavy metals.

Among the many other low cost adsorbents, chitosan has the highest sorption capacity for several metal ions. Chitin (2-acetamido-2deoxy-b-D-glucose-(N-acetylglucan)) is the main structural component of mollusks, insects, crustaceans, fungi, algae, and marine invertebrates like crabs and shrimps. Obtaining chitosan hardly counts as a loss since at present, the solid waste from processing of shellfish, crabs, and shrimps constitutes a large amount of chitinaceous waste.
Chitosan with a structural group of 2-acetimado-2-deoxy-b-D-glucose-N-acetylglucosamine is a partially deacetylated polymer of chitin and is usually prepared from chitin by deacetylation with a strong alkaline solution. It adsorbs five to six times greater amounts of metals than chitin. This is attributed to the amino groups exposed in chitosan because of deacetylation of chitin.

The time it takes to bioremediate a site depends on several factors:
• Types and amounts of harmful chemicals present
• Size and depth of the polluted area
• Type of soil/water and the conditions present
• Whether clean up occurs above ground or underground

These factors vary from site to site. It can take a few months, or even several years for microbes to eat enough of the harmful chemicals to clean up the site.
Properties of Arsenic
Arsenic is a semi-metallic element. Arsenic and its compounds are known to be toxic.
It has two forms. The grey metallic version has a density of 5.73g/cm3 and the yellow form that has a density of 1.97g/cm3.

Key Properties of Arsenic

Arsenic and its compounds are known to be toxic. Arsenic does not melt, it sublimes, going directly from a solid to a gas.

Property Value
Symbol As
Atomic Number 33
Atomic Weight 74.92
CAS Number 7440-38-2
Density 5.73g/cm3
Melting point 817˚C
Boiling Point 617˚C
Specific Heat 330J/kg.K
Electronegativity 2.18

Applications

Metallurgy
Arsenic is used as an additive for metallurgical purposes due to its semi-metallic properties. Examples include: adding 2% to lead to produce lead shot where the addition increases sphericity; a 3% addition to lead alloys increases mechanical properties and high temperature properties; and 0.15-0.50% addition to copper for high temperature applications.
Semiconductors
Arsenic compounds are used as semiconductors. In particular gallium arsenide (GaAs) is used in diodes, transistors and lasers. Indium arsenide (InAs) is used in infrared detectors and Hall effect applications.
Properties of Lead
Lead can end up in water and soils through corrosion of leaded pipelines in a water transporting system and through corrosion of leaded paints. It cannot be broken down; It can only be converted to other forms.
Lead accumulates in the bodies of water organisms and soil organisms. These will experience health effects from lead poisoning. Health effects on shellfish can take place even when only very small concentrations of lead are present.
Soil functions are disturbed by lead intervention, especially near highways and farmlands where extreme concentrations may be present.
Lead is a particularly dangerous chemical, as it can accumulate in individual organisms, but also in entire food chains.

KEY PROPERTIES OF LEAD
Property Value
Atomic Number 82
Atomic Mass 207.2 g/mol
Electronegativity 1.8
Density 11.34 g/cm-3 at 20° C
Melting Point 11.34 g/cm
Boiling Point 11.34 g/cm
Ionic Radius 0.132 nm(+2); 0.084 nm (+4)
Isotopes 13
Specific Heat 0.0305 cal/g° C

Other Details Ü

Heavy metals waste has increased rapidly since the industrial revolution. Toxic metal species are mobilized from industrial activities and fossil fuel consumption and eventually are accumulated through the food chain, leading to both ecological and health problems. Procedures for the removal of toxic metal species from contaminated environments have been developed and most of them are based microbiology or the use of microorganisms in cleaning up contaminated water sources. Unfortunately, these methods are expensive and require the use of contaminating products for desorption of metals for cleaning up of the inorganic matrix.

Chitosan is derived from chitin, a polysaccharide found in the exoskeleton of shellfish such as shrimp, lobster, and or crabs. Chitosan has shown some absorptive properties but not in the field of Biochemistry. At first, it was proven that it can serve for the purpose of losing weight since it does absorb fat. Since it can absorb fat, it's possible that it may also absorb other materials such as heavy metals (e.g. lead, arsenic, mercury, and others). So basically, the idea is to use crab shells as possible bioremediators. It is economical because crab shells are only thrown as waste products. It will be powdered and then placed into a contaminated water sample to see whether it can absorb the heavy metals in that sample although it is better if the chitosan or chitin can be extracted from the shells. That will probably produce more accurate results.

Background of the Study [Draft]

The world is in chaos. This is because of a lot of factors but largely because of the environment. Pollution, one of the leading causes of environmental degradation is flooding our world at present. Our country is of no exception. Pollution comes in different kinds and though simple solutions have been presented by authorities, we cannot deny the fact that there are some types of pollution which needs more than avoidance and prevention; one of which is water pollution.

Water pollution does not only include the garbage which float on surfaces of the bodies of water but also the composition of the water itself. Specifically, heavy metals; these heavy metals pollute the water making it unsafe for any possible use. Studies were done mainly for the sake of finding a solution to the contamination of bodies of water with heavy metals such as arsenic, lead, mercury, and others. The idea is to develop a specimen that can absorb the heavy metals from a contaminated source. Various researches have been improved and developed for the better. Requirements for a successful bioremediation response are now known. First, the specimen must have a property that can stimulate a response for the absorption of the heavy metals and second, though not particularly required but more appropriate, is it must be easily retrievable if large bodies of water are involved.

The researcher has chosen the use of crab carapace or the outer shell of a crab. It is economical since the crab carapace is a waste product. It has a component known as chitin which has a property of absorption. Chitin is a protein which is mainly the composition of the crab carapace. What gives the absorption property however is not chitin but its derivative which is known as chitosan.

Crab Carapace as a Bioremediator of heavy metals such as Mercury (Hg)

Water pollution is one of the rising problems of our country at present. This is supported by the evidence that a lot of researches are done to help decrease the said problem. I decided to make a research in relation to Environmental Science and Biochemistry. One of main causes of water pollution is the heavy metals which are contained in the bodies of water. Bioremediators are used to absorb the heavy metals. These bioremediators are mostly waste materials which should be easily retrievable. My idea is to use crab carapace as a possible bioremediator.

This is because of a property or substance present in the crab carapace-Chitin. Chitin composes the exoskeleton of the crab but the most important property lies deeper than that which is the Chitosan. It is a polysaccharide and is known to be a good absorber of fats and other substances. I started with this topic this January 5 onwards.

Kick Off

Day 3: Unexpectedly, this year's intramurals was set foot to another event-The Sepak girls.Sepak takraw or kick volleyball is a sport native to Southeast Asia, resembling volleyball, except that it uses a rattan ball and only allows players to use their feet, knee, chest and head to touch the ball. It's rare enough for girls to kick the ball in Sepak well since it's really a difficult skill to master. However, it's also not surprising that the players from the 4 teams were able to learn that skill in a short period of time.
Game 3 of Sepak girls introduced the Blue Vaio vs. the Red Macintosh. With the service given to the red team, they were off to a good start. The team consisted of one thrower, a server, and another player as a receiver. During the first set, the game was in favor of the Red Macintosh with the team gaining a score of 21 as a first. The Blue Vaio only needed a few points during that same set to win since they were able to gain 18 points. During the second set, the Red Macintosh rocketed to the top at only for a short period of time. They gained points mostly because of successful services. The Blue Vaio only had 12 points, a far point range from the red team's score.

The game ended with the Red Macintosh being declared as the winner and of course the usual "hand shake" as every team member moves around half of the court from the end line. Ü

Join The Rhythm

Day 2:

Basketball girls definitely stood out as one of the main events during this year's intramurals. Aside from the fact that it would just be held starting this year, it also grabs most people's interests.

The first game of basketball girls was between teams A and B, otherwise known as the Green Acers Vs. the Red Macintosh. Basketball girls only consisted of 3 quarters mostly in favor of the Red MacintoshThe first quarter began with 13 points from the Red team and an unlucky part for the Green team since they were not able to have any successful shots. Most players shoot as near as possible because it was really difficult to shoot at a far distance for them. Of course, high shrieks and yells were always present as every team member gave his support.

During the second quarter, the Green Acers managed to gain 8 points but they were still far behind. By that time, the Red Macintosh had already gained 28 points.
Tension filled the air for the 3rd and final quarter. Unfortunately for the freshmen, they didn't get any points from their previous one and thus the game ended in favor of the juniors with 34-8 as the final score. Ü

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