Motivation The worst oil spill in US history is getting worse every single day: about 1.5 million gallons of crude oil are being spewed each day into the Gulf of Mexico as a result of the BP/Deepwater Horizon accident. Over 1 million gallons of chemical dispersants have been used in an effort to break up the oil spill, a huge amount that causes concerns for the wildlife and humans exposed to it. It is clear that the oil clean up efforts will be intense, and the environmental impact will be persistent. There is an urgent need for fundamental information on oil dispersant interactions that would facilitate the reformulation of dispersants so as to render them safer toward wildlife and human health. Also, a need for fundamental information on interactions between crude oil and mineral particles.
Proposed Research
In response to the oil spill crisis, the PI proposes to (1) advance methodologies that facilitate the reformulation of currently used dispersants, so as to reduce/replace hazardous ingredients, and (2)develop oil dispersants based on mineral particles that will have low impact on the environment. (1) Oil and dispersant will be brought into contact in a controlled, aqueous environment at a scale of (i) an individual oil drop (novel set-up) and (ii) large populations of drops (current EPA test), and the information obtained from the two setups will be analyzed/synthesized in order to (a) generate data on oil-surfactant interactions at the molecular/nanoscale level, (b) resolve the contribution to the dispersion of the individual components f the disper-sant, and (c) facilitate the optimization of dispersant formulation through the use of the single-drop methodology that will be developed here. (2)(i) The wetting and adhesion of crude oil on a variety of mineral surfaces (related to sand and sediment) will be characterized, and these findings will be analyzed in terms of surface free energy parameters that can be subsequently used to predict wetting/adhesion behavior in a variety of conditions. (ii) The emulsification of crude oil in the presence of mineral particles, and also in the presence of mineral particles and molecular surfactants, will be studied (seeking synergisms), and the results will be analyzed so as to evaluate the efficacy of natural, mineral particle based dispersants.
In order to address the issue of variability in nature, conditions will be varied systematically, and model compounds (API standards) and specimens collected from the Gulf area will be tested. The single drop methodology will facilitate rapid testing to handle the natural variability in crude oils.
Intellectual Merit and Novelty
This project will contribute to the fundamental knowledge (currently lacking in the published literature) on interactions between crude oil and dispersants (as a formulation and as its individual components), and on interactions between crude oil and mineral particles. This work will expand the current options by exploring the suitability of alternative carrier solvents (e.g., food grade, alternative surfactants (e.g., alkyl glucosides), and mineral particles as surface active agents. The connection between the EPA flask dispersion test and a newly developed single drop dispersion methodology could enable high throughout screening of dispersants, paving the way for rapid reformulation of dispersants in response to a given oil spill. The development of novel mineral particle based oil dispersants provides an opportunity to use natural ingredients to combat oil spills, and adds to our oil-mineral interactions knowledge needed for coastline remediation.
Broader Impacts
Outcomes of the proposed work could aid in an immediate, objective, and independent evaluation of the current situation as it has evolved in the water (oil dispersion) and at the coastline (oil deposition on minerals), will inform decisions on what types and quantities of dispersants are appropriate to use, as well as decisions on how to treat shorelines and biosurfaces in order to remove residual oil. The work will be carried out by academic researchers who have no conflict of interest with oil companies and will openly share their data. Several graduate and undergraduate students will be involved in research, including members of groups underrepresented in science and engineering. Chemical Engineering juniors and seniors will complete course projects related to this topic.
As a result of the BP/Deepwater Horizon accident in 2010, unprecedented amounts of crude oil were released in the Gulf of Mexico. Over 1.5 million gallons of chemical dispersants were used in an effort to break up the oil spill, a huge amount that causes concerns for the wildlife and humans exposed to it. While the leak was eventually contained and the spill was cleaned, the environmental impact of the oil and the dispersants used is persistent and the debate as to the long term effects of dispersants is ongoing. This project has been motivated by the lack of fundamental information on the interactions between dispersants (or their main ingredients, e.g., surfactants, solvents), water, oil, and naturally occurring particles in aquatic environments. Such knowledge can facilitate the reformulation of dispersants so as to render them safer toward wildlife and human health. Research activities under the project focused on the interactions of nonionic surfactants with silica particles as affected by particle/surfactant concentration, particle surface properties, solution pH, temperature, added salt, and presence of polar organic solvents or polymers. The presence of attractive interactions between the nonionic surfactants and silica and the modulation of such interactions by polar organic solvents was established. The emulsification of oil (different types) in water with the use of (i) nonionic polymeric surfactants, (ii) silica nanoparticles, and (iii) mixtures of nonionic polymeric surfactant and silica nanoparticles was also investigated. Conditions for synergistic effects between particles and surfactants in the stabilization of water and oil emulsions were determined. These results have been presented in scientific conferences and have been disseminated through Master’s theses and journal publications. The research conducted under the grant contributes to knowledge for the development of future dispersant formulations that can potentially limit the environmental, ecological, economic, and socio-cultural impacts of large oil spills. This grant has also partially supported the acquisition of a state-of-the-art instrument, a Quartz Crystal Microbalance (QCM-D, QSense, Biolin Scientific) to enable studies on interactions of oil with mineral surfaces. The instrument is the only one available at the North Campus of the University at Buffalo, and will continue to be used for studying molecular interactions and surface phenomena in various research projects. The project provided ample opportunities for the training and development of graduate (Master of Science and PhD) and undergraduate students (including two members of underrepresented in science and engineering groups) at the University at Buffalo on emulsion stability and evaluation of dispersant effectiveness for oil spills as well as related characterization methods. To provide a forum for the dissemination of research on aspects pertaining to this project, the PI organized a Symposium entitled 'Environmental Impact of Surfactants, Colloids, and Nanomaterials' at the 242nd National Meeting of the American Chemical Society in 2011 and a Session on "Environmental Aspects of Interfacial Science and Engineering" during the American Institute of Chemical Engineers (AIChE) Annual Meeting in 2012. Furthermore, there were several educational activities that were completed in association with this project. The PI introduced two lectures and a term project on oil dispersion and remediation into the existing Colloid & Surface Phenomena, an elective senior undergraduate and graduate-level course. A workshop on the topic Oil and Water do Mix was organized and presented at the Tech Savvy middle and high school student conference, held by the American Association of University Women (AAUW). This day-long conference attracts over 500 participants (girls mainly from the Buffalo Public Schools) to our University and allows them to see science in action. The program includes a wide range of presentations, workshops, fun hands-on activities, and concludes with an inspiring lecture by a community leader educated in STEM.
