From carbon nanotubes to sawdust and cellulose to fern-inspired nano-hair, a multitude of materials are showing great promise for cleaning up oil spills. Now researchers have turned to waste products from the industry responsible for the problem in the first place. Using by-products of the petroleum and refining industries, they've created an absorbent polymer that can quickly soak up crude oil from sea water.
The new polymer, created by an international team led by Dr Justin Chalker at Flinders University, is made from used cooking oil, sodium chloride and sulfur, making it sustainable and cheap to produce. Because sulfur and cooking oils are hydrophobic, the resulting low-density polysulfide polymer is able to soak up hydrocarbons like crude oil and diesel, while repelling water.
"This is an entirely new and environmentally beneficial application for polymers made from sulfur," says Dr Chalker. "This application can consume excess waste sulfur that is stockpiled around the globe and may help mitigate the perennial problem of oil spills in aquatic environments."
In experiments conducted in the lab, when the polymer was sprinkled onto oil floating on the surface of water, it acted like a sponge to absorb the pollutant within a minute. Even better, the oil can then be recovered by squeezing the highly buoyant material, which can then be used to soak up more oil. Although a film of oil remains on the surface of the material after being wrung out, the team says this didn't have a major impact on its subsequent performance, which was found to be similar over five sorption and oil recovery cycles.
"This is a new class of oil sorbents that is low-cost, scalable, and enables the efficient removal and recovery of oil from water," says Dr Chalker.
The video below provides an overview of the polymer, which is detailed in a paper published in the journal Advanced Sustainable Systems.
Source: Flinders University