Nano-Engineered Sponge Can Suck up 99% of Oil From Cold Water

Cleaning oil from water at low temperatures is a big problem that's waiting to be solved. This nanocoating might help.
Derya Ozdemir
Arctic Tundra Wetlands, AlaskaGRID-Arendal/Flickr

As a devastating consequence of old equipment, human error, and bad luck, oil spills have adversely affected the environment throughout the years by releasing millions of gallons of oil along coastlines, polluting fisheries, killing and injuring wildlife. The news of such spills is announced with worrying frequency, with one of the most recent examples being the devastating Mauritius spill.

In that particular accident, the volunteers were able to collect some of the oil using their freshly cut hair; however, when a spill happens in, let's say, the Arctic, it becomes even bigger of a problem since, in cold water, oil can be much more difficult to clean up.

This happens because of crystallization. At low temperatures, crude oil's heavier compounds, including the roughly 2.44 percent of the oil that is natural paraffin wax, begin to crystallize, and the resulting paraffin crystals then link together to form a larger, more viscous mess for people to clean up. Up until now, technologies on this front, such as heating oil-stricken water to break down the molecules, have been inadequate and impractical. 

Now, a team of researchers at Imperial College London have come up with a different method to tackle this dangerous problem. "We’re trying to keep the oil as it is, then develop the sponge to capture it," explained Dr. Pavani Cherukupally from the Department of Chemical Engineering to New Scientist. "This means we don’t have to do the pre-heating process and can directly tackle the problem."

By analyzing the molecular structure of the sticky oil, Cherukupally was able to engineer a nanocoating with a near-identical structure. According to the study published in Science Advances, when a sponge is covered with this paraffin-like nanocoating, it turns into an oil-sucking machine that, in one test, was able to absorb up to 99 percent of Texas raw crude oil mixed into 100 milliliters of water within 3 hours in low temperatures such as 5°C. Then the oil was drained by soaking it in a solvent. 

The coating was able to withstand at least 10 further uses, but whether it can last beyond 10 wasn't tested since experiments take a long period of time. 

While similar sponges were developed in the past, this one sticks out from the rest since it focuses on lower temperatures. The majority of oil exploration and production is located in the Arctic, so this could be of great use in case of another oil spill. Now, the next step will be to improve laboratory tests by enhancing the product's efficiency.  

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