A barrel designed to spontaneously remove oil from water could offer a rapid and simple remedy to spills at sea.
Millions of gallons of oil enter the world’s oceans each year, yet oil clean-up methods, including floating barriers, sponges and dispersants, are often slow, complex or inefficient.
Now, scientists in China have developed a cylindrical container that, dropped into contaminated water, collects oil through an array of microscopic holes in an aluminium sheet. The outer face of the sheet is fluorinated and highly hydrophobic, attracting oil through the holes, but not water. The inner face is highly hydrophilic and pre-coated with water, preventing exit of the collected oil.
This two-faced ‘Janus barrel’ can soak up surface slicks as well as oil droplets dispersed in choppy water. Once collected, the oil can be easily syphoned out of the barrel, which can then be immediately reused. So far, the team have only tested small-volume barrels, but they work quickly. A scaled-up version could collect thousands of litres of oil in minutes.
Z Zhang et al, Nanoscale, 2017, DOI: 10.1039/c7nr03829a