Deepwater Horizon oil spill is now threatening the Gulf Coastline and the wildlife and economies that depend upon this region. Mitigation of the effects of the oil on the land and wildlife could be achieved if the deposition of the oil onto these substrates could be prevented. In this context, deposition of oil onto substrates is routinely achieved in laundry by the use of polymeric soil anti-redeposition agents. This RAPID project seeks to investigate the propensity of these agents to mitigate the effects of oil deposition on the Gulf Coast. The project will identify effective oil anti-deposition aids that are nontoxic, biodegradable and available commercially in amount large enough to mitigate the effects of the Deepwater Horizon oil spill on the Gulf Coastline. These agents are polymers that essentially sterically-stabilize the oil droplets and prevent close approach at which attractive London dispersion forces would operate. However, the Gulf is much larger than a laundry load, the oil in the Gulf is overwhelming the system, and the water is seawater rather than freshwater. These are significant unknown variables. Nevertheless, it is worthwhile exploring the use of oil anti-deposition agents for their possible effect in mitigating this disaster. The most commonly used soil anti-redeposition agents are cellulose ethers, which are available inexpensively in large commercial quantities. Carboxymethylcellulose ethers are listed on the EPA subinventory. These are not likely to accumulate in the food chain due to their water solubility and high molecular weight (bioconcentration potential is low). They are nontoxic to fish and aquatic organisms on an acute basis. They are expected to slowly biodegrade in the aquatic environment. These compounds are already released into the environment in vast quantities as a consequence of their widespread use in laundry detergents. There are also Marine proteins that are by-products of fisheries that will be investigated in the proposed research, for their ability to prevent oil from sticking to coastal substrates. The search for anti-deposition aids normally would be expected to require years of intensive effort. However, as a consequence of the high throughput laboratory and concomitant skill sets that has been built under the aegis of the Partnerships for Innovation program (PFI Award 0917730), the Principal Investigator has considerable knowledge of the science of consumer goods, such as laundry detergents, and he will lead the high throughput screening effort with state-of the art robotic liquid handlers and micro-channel emulsification devices. This study will also provide a basis for the real understanding of the role of adsorbing hydrophilic polymers on seawater substrates for the purposes of anti-deposition.
If successful, the knowledge gained will mitigate the effects of the current catastrophic oil spill and provide materials to tackle future similar disasters. The project will educate the scientific workforce on combinatorial experimentation methods, and in response to crises.
NSF Rapid Project 1047662 was funded with the overall objective to mitigate the deposition of oil on solid coastal surfaces including soil, sand, plant and wild-life. The limitations of the proposed application require that the materials used must be well-known commodities and the technology should be either reduced to practice or show significant promise from its use in other applications. We proposed to investigate the use of soil anti-redeposition agents, which are commercial products that are currently used in laundry to prevent deposition of oils on fabrics during rinsing when surfactant concentrations drop below the critical levels to keep the oil suspended. This RAPID project proved the concept that it was possible to conceive of a dispersant for spilled oil having the properties: The dispersant easily dispersed the oil with only minimal agitation. Once dispersed, the oil did not adhere to bird feathers.The dispersant consisted of food-additive type materials that are abundantly available.In particular, the dispersant comprised lecithin and either hydroxypropylcellulose or hydroxypropylmethylcellulose. Successful formulations adsorbed viscoelastic layers that exhibited more solid-like than liquid-like characteristics. We hypothesize that the lecithin acts as primary emulsifier and also chaperones the cellulose ether to the oil-water interface. The ‘non-stick’ properties are hypothesized to result from the sterically-stabilizing layer of hydrophilic polymer which is anchored to the oil droplet by the lecithin. The concept formulation appears to be cost-effective in comparison with current commercial dispersants. Outlook: This project has now been funded by an NSF Accelerating Innovative Research grant (1127846) that has provided the funding to already successfully develop a working prototype which at the present time has been scaled to pilot scale.
