Study Describes Mechanics of Dispersant Adsorption at Oil-Water Interface


Oil in the wake of a boat. (Photo credit: NOAA Gulf Spill Restoration)

Scientists are trying to develop more stable, safer dispersants.  Carnegie Mellon researchers examining the chemical interaction of Tween 80 (a primary component in typical dispersants) at the point where oil and water meet have characterized dispersants behavior in variable test environments. They observed reorganization, irreversible adsorption, and high values of surface elasticity. The researchers discuss these and other results in terms of their impacts on oil spill response measures.  They published their findings in the January 2013 issue of Langmuir: Interfacial Tension Dynamics, Interfacial Mechanics, and Response to Rapid Dilution of Bulk Surfactant of a Model Oil−Water-Dispersant System.

The usefulness of dispersants is their ability to help oil stay broken up in small particles so that bacteria have a longer time to eat it, despite the reduction of dispersant concentration as it mixes with the ocean and its use under varying water conditions. Understanding the “more complex adsorption processes where application conditions include step changes in concentration” is critical knowledge that affects decisions about dispersant application. To do this, scientists used Tween 80 as a dispersant proxy, along with squalane and artificial sea water, to develop a model to better track and measure the mixing of oil and water and the stability of that mixture.

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