Amphiphilic Star Polymers (ASPs) and Amphiphilic Grafted Nanoparticles (AGNs)
As a part of the research that GoMRI has funded, a professor named Scott M. Grayson of Tulane University has developed a project exploring the use of unimolecular micelles as oil dispersants. A micelle is the structure formed when a molecule with a hydrophobic tail and hydrophilic head suround an oil droplet, the tail anchored to the oil and the head partitioned to the water. Unicellular micelles are different in the sense that it takes only a single molecule to form the micelle through the encapsulation of the oil by the polymer.
Grayson has proposed to study two complimentary molecules that will theoretically be able to form the unimolecular micelles. To create the first molecule, amphiphilic star polymers, Grayson uses a technique where he combines preformed block polymers into a single complex molecule. These block polymers are dendrimers that contain varying numbers of alkyne groups (hydrocarbons with at least one double bond between carbons) and an azido group (a functional group containing three nitrogen molecules with a total negative charge). In order to synthesize the amphiphilic grafted nanoparticles, silica nanoparticles will be modified using functional groups to give them amphiphilic properties. The advantage of using molecules such as these comes from the fact that their effectiveness will not be diminished by the unlimited dispersing capabilities of the open ocean.
Grayson has already determined a way in which to create the ASPs through synthetic means and in such a way that he can create molecules of varying sizes and composition. There will be a similar process developed to create the AGN particles as well. The goal of this research is to ensure that these compounds are effective as dispersants as well as easy and cost efficient to manufacture.
Source: GoMRI Project Library
Grayson has proposed to study two complimentary molecules that will theoretically be able to form the unimolecular micelles. To create the first molecule, amphiphilic star polymers, Grayson uses a technique where he combines preformed block polymers into a single complex molecule. These block polymers are dendrimers that contain varying numbers of alkyne groups (hydrocarbons with at least one double bond between carbons) and an azido group (a functional group containing three nitrogen molecules with a total negative charge). In order to synthesize the amphiphilic grafted nanoparticles, silica nanoparticles will be modified using functional groups to give them amphiphilic properties. The advantage of using molecules such as these comes from the fact that their effectiveness will not be diminished by the unlimited dispersing capabilities of the open ocean.
Grayson has already determined a way in which to create the ASPs through synthetic means and in such a way that he can create molecules of varying sizes and composition. There will be a similar process developed to create the AGN particles as well. The goal of this research is to ensure that these compounds are effective as dispersants as well as easy and cost efficient to manufacture.
Source: GoMRI Project Library
The Use of Biosurfactants in Oil Spill remediation
Biosurfactants are surfactants created through the metabolic processes of microorganisms. These substances offer a unique solution to the problem of toxic dispersants used to remediate oil spills. Hisashi Saeki and colleagues have shown that a biosurfactant produced by Gordonia sp. is not only comparable to commercially available dispersants, but is also feasible to manufacture on a large scale. When the Gordonia sp. were fed hydrocarbons, one of their metabolic by-products has a structure that is able to effectively disperse oil. Not only do they disperse the oil, but it was also proven through their experiments that the oil was more readily degraded by microorganisms after the addition of the biosurfactant than when only additional nutrients for the organisms were added. When attempting to produce the surfactant on a large scale Saeki et al. was able to achieve an approximate yeild of 55% based upon the amount of hydrocarbon added to the broth in which the microorganisms were growing.
Biosurfactants are not only being used as dispersants, but can also be applied to the recycling of sorbent materials. Sometimes oil is removed from the ocean using materials that will absorb it, or sorbent matierals. Q.F. Wei et al. wanted to find a way to divert these oil soaked materials from landfills, where they usually are sent after they are used. Certain biosurfactants that are typically used to wash oil from soils, can also be used to clean the oil from sorbent materials. According to these experiments, the biosurfactants can remove up to 95% of the oil from the materials, depending upon the oil, sorbent material characteristics, and ambient temperature.
Biosurfactants are not only being used as dispersants, but can also be applied to the recycling of sorbent materials. Sometimes oil is removed from the ocean using materials that will absorb it, or sorbent matierals. Q.F. Wei et al. wanted to find a way to divert these oil soaked materials from landfills, where they usually are sent after they are used. Certain biosurfactants that are typically used to wash oil from soils, can also be used to clean the oil from sorbent materials. According to these experiments, the biosurfactants can remove up to 95% of the oil from the materials, depending upon the oil, sorbent material characteristics, and ambient temperature.
References
Grayson, S. (n.d.). Project Overview- Development of Cost-Efficient and Concentration-Independent Dispersants for Improved Oil Spill Remediation. http://research.gulfresearchinitiative.org/research-awards/projects/?pid=227
Saeki, Hisashi, Sasaki, Masaru, Komatsu, Koei, & Matsuda, Hitoshi (2009). Oil spill remediation by using the rediation agent JE1058BS that contains a biosurfactant produced by Gordonia sp. strain JE-1058. Bioresource Technology, 100(2), 572-577. http://dx.doi.org/10.1016/j.biortech.2008.06.046.
Wei, Q.F., Mather, R.R., Fotheringham, A.F. (2005). Oil removal from used sorbents using a biosurfactant. Bioresource Technology, 96(3),331-
334. http://dx.doi.org/10.1016/j.biortech.2004.04.005.
Saeki, Hisashi, Sasaki, Masaru, Komatsu, Koei, & Matsuda, Hitoshi (2009). Oil spill remediation by using the rediation agent JE1058BS that contains a biosurfactant produced by Gordonia sp. strain JE-1058. Bioresource Technology, 100(2), 572-577. http://dx.doi.org/10.1016/j.biortech.2008.06.046.
Wei, Q.F., Mather, R.R., Fotheringham, A.F. (2005). Oil removal from used sorbents using a biosurfactant. Bioresource Technology, 96(3),331-
334. http://dx.doi.org/10.1016/j.biortech.2004.04.005.