Oil Spill Cleanup
Oil spills seem to become common news story. The most recent confirmed oceanic oil spill happened early this year, January 6th 2018 in the East China Sea. 138 tons of crude oil slicked the ocean causing significant ecological and economic damage.
But what is crude oil, why is it harmful, and why is it so hard to clean up?
Crude oil is dead organic matter of eons past that have been buried heated, and compressed under the earth for thousands of years. It comes in several forms and viscosities, but they are all made up of hydrocarbons (molecules comprising of hydrogen and carbon) and other traces but hazardous compounds. It is prized because when burned, hydrocarbons molecules release a lot of chemical energy. To do so reliably the oil has to be refined, but before it is refined it is rather toxic due to the trace hazardous compounds, and because of the physical properties of oil. This is why oil spills are such an ecological hazard.
Oil, including all crude oil, is less dense than water, it floats. It is also immiscible, meaning it doesn’t mix in with water. These two physical properties mean that oil spills like to spread themselves out in thin layers across bodies of water, covering an immense area. Because of it doesn’t mix with water, it is also very hard to clean off of rocks, coral, birds, and other sea life. It coats these creatures readily, detrimentally impacting their health and ability to live normally.
The sheer scale, behavior, and general toxicity of crude oil makes it very hard to clean up.
For our activity we explored different methods used to clean up oil from water using spoons (for skimming), cotton balls and absorbent powder (booms and absorbents), and soap (surfactants/emulsifiers). Each student was given their own bowl of water and oil to attempt to clean up. In practice, no one method was perfect and all methods were used to get best results.
Since the students were interested in how emulsifiers worked, we also looked at a video on how soap molecules are polar, one end being oleophilic (oil loving) and the other hydrophylic (water loving). These molecules like to bunch together around oil, breaking it up and effectively covering them in a soapy skin. This prevents the oil from grouping together or sticking to surfaces (like a bird or dinner plate).
This was our last class before the summer season. It was a veritable pleasure introducing these young bright minds in the wonders of oceanography.
— Sydney