It’s 2012. You can travel almost anywhere in the world in a matter of hours. You’re probably carrying a miniaturized computer in your pocket. But when the next major oil spill happens, like the Deepwater Horizon accident in 2010 that spilled enough oil to fill 300 Olympic-size swimming pools, will we really clean it up with corncobs and straw, as we’ve done for decades?
Spill response teams are still using low-tech absorbents like those mentioned above. That could change thanks to a new superabsorbent material that can soak up 45 times its own weight in oil. It’s described in a paper in ACS’ journal Energy & Fuels.
Current absorbents, like plant matter, can only hold about 5 times their own weight in oil, and they tend to absorb water at the same time, unlike the new absorbent. After doing the job, the oil-soaked corncobs and straw become industrial waste that is either buried in special landfills or incinerated. That can be expensive, and the process raises additional environmental concerns.
Authors T.C. Mike Chung and Xuepei Yuan describe a new polymer absorbent, one pound of which can absorb about 5 gallons of crude oil. The resulting gel is stable enough that it can withstand waves and sun as it floats on the surface, and strong enough to then be picked up and collected. Afterward, a refinery can recover the absorbed oil.
The polymer is a network of interlinked carbon chains and rings. Crude oil contains similar shapes packed loosely together. These molecules fill in the empty spaces in the polymer web, swelling it up to 40 times in size.
The new technology is inexpensive, too. The authors estimate that it would cost about $2 per pound when it’s being produced on a large scale. If crude oil was selling for $100 barrel, a pound of the absorbent could sop up and deliver $15 in crude oil.
Finding a better way to clean up large oil spills is important because of their often disastrous consequences. In addition to killing 11 men working on the rig, the Deepwater Horizon spill killed thousands of animals living in and near the Gulf of Mexico and cost tens of billions of dollars in losses for the regional tourism and fishing industries.
The polymer (a) swells as it absorbs oil from water (b). At right (c), it has been lifted from the water with tweezers.
Credit: American Chemical Society