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Corexit Project.docx

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Boston College
CHEM 1105
Riley Mcminn

Chemistry and Society November 22 , 2011 Corexit Project Research Paper Dispersants are liquid solutions of detergent-like surfactants dissolved or suspended in solvent. The surfactants have two ends: one attracted to oil and the other attracted to water. The water-compatible chemical is called Hydrophilic and the oil compatible chemical is called Lipophilic. The solvent enables the surfactants to be applied and helps get them through the oil film to the water interface.At the interface the surfactants reduce the surface tension allowing the oil to enter the water as tiny droplets, which are degraded by natural bacteria. One must take note that seawater contains stronger internal attractive forces between the bonds due to the addition of sodium and chloride. Seawater is considered polar while oil is non-polar.As a result, the oil relaxes on the surface of water due to density. If one wants to clean oil from the seawater, one must somehow make oil compatible with water because of soluble ends. Using surfactant blends, one can obtain a balance with Hydrophilic and Lipophilic chemicals. The goal is to reduce oil concentration to less than impact levels as rapidly as possible. The process is tedious but simple. Since oil and water are not compatible, the application of dispersant HLB causes the oil slick to disperse into tiny droplets with small amounts of energy. Consequently, the surface of droplets repels each other resulting in no blockage or coalescence. th Corexit was a type of solvent developed in the late 20 century. It contains over 60% surfactants plus ethylene and glycol monobutyl ether. The chemical names are propylene glycol, 2-butyoxyethanol, and dioctly sodium sulfosuccinate. Corexit 9527 remains the most widely approved and stockpiled dispersant in the world. None of the Corexit chemicals were designed for direct application to shorelines and thus, Corexit 9580 was developed. Since then, it has been extremely successful, and it was used to break emulsions. However, it was not effective against large oil spills. Since heavy oil spills were involved with over half of the spills, scientists needed to develop a dispersant to fix this problem. In 1992, the Corexit 9500 was formulated specifically for weathered oils and huge oil spills. The problem with the older Corexit chemicals was that the old solvent was being extracted before delivering the surfactant to the interface in heavy oil. Corexit does not really differ from other dispersants except that it contains more complex glycol ether and paraffin solvent when compared to others. In fact, the only reason why BP chose Corexit is because it was the only chemical available the week of the rig explosion. Technically, Corexit has a below average rating compared to other chemicals as far as efficiency and toxicity. Rumor has it that BP used Corexit because of their close relationship with its manufacturer Nalco. Even its solvent solubility in water is very low whereas the others are somewhat infinite. The pros of using the chemical dispersants are that the chemicals are used to break up the oil and make it food for the tiny microorganisms near the surface. Because the chemicals do not sink, the method only works if they hit the water’s surface. Moreover, it has a high and efficient success rate. On the flipside, the cons are that the chemicals being dispersed are toxic to coastal plants and wildlife. In small amounts, the damage is small, but if the leak cannot be fixed, the dispersant will have to be used over and over. If one is in contact with the water that contains the dispersant, if not used properly, the chemicals will cause eye irritation, dermatitis, nose and throat irritation, and liver and kidney damage. Basically, the main con was how toxic the chemical dispersant was and the side effects it had on nature and mankind. Using chemical dispersants on land compared to under water is extremely different due to the fact that the increasing activity of the microbes eating digesting the oil underwater will reduce the oxygen in water. Other problems were that scientists claimed that the dispersants, which are liable to cause cancer and other mutations, add to the level of toxicity of the oil spill and organisms are at a greater risk when the dispersant is applied. Endangering some of the fish that humans eat at a daily basis can easily harm the health of innocent human beings. It is very different when paralleled to dispersing chemicals on land because the process of cleaning up things that are not diluted in water is simple. In water, the chemicals spread rapidly and attract to some of the biological organisms in the sea that humans consider as food and nobody will
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