We all cause accidental spills from time to time and immediately reach for something to clean up the mess. Large-scale oil spills are in a different league from minor domestic dramas, however. Cleaning them up is much more complex than just wiping with a cloth.
Help with this major global problem may be on the way. Researchers in China created bundles of polymer microfibres that might allow oil and other chemical spills to be mopped up more easily and cheaply.
“More affordable and effective ways to clean up oil spills are urgently needed,” says Xianhu Liu of the National Engineering Research Center for Advanced Polymer Processing (APP-NERC) in China, where they made the new polymer bundles. The manufacturing procedure and initial test results are published in the journal Applied Materials Today.
Existing clean-up methods include burning off the oil, trapping it within floating booms, dispersal with detergents, and using various materials as absorbents or filters. “The current methods all have shortcomings, however, such as complicated and time-consuming production methods, high costs and environmental impacts,” says Liu. He believes that physical methods to absorb the oil are the most promising because they avoid the secondary pollution created when burning or using detergents.
The researchers describe their approach to fixing these problems as an “environmentally-friendly, low cost and efficient” method to continuously make porous microfibres of polyethylene. This is a material familiar to us from grocery store bags. Some clever processing involved in making the microfibres, creates cross-linked channels that are highly efficient at attracting large quantities of oil.
Tests demonstrate the material is excellent at mopping up different organic chemicals from a water/oil mix. It can also be made to release the collected oil very simply using a centrifuge, essentially by just sending it for a spin. Another major feature is reusability — there is no loss of effectiveness even after 100 cycles of clean-up and release.
Xianhu Liu believes that the procedure might be made even more efficient by trying out various modifications to the manufacturing process. This will be a focus for future development by the research team. Another key aim will be to find an industrial partner interested in taking on and scaling up the proof-of-concept work already done.
If everything pans out as hoped, the microfibre bundles may soon help clean up the world's oil spills in a quicker and cheaper way. "Every boat or chemical plant could have some, like they now have fire hydrants," says Liu. He explains that it could be dragged through the pollution, or dumped overboard and then later collected. And if centrifugation is not immediately available, much of the oil could be wrung out like water from clothes.
This story is adapted from Wang, Y. et al.: "Continuous fabrication of polymer microfiber bundles with interconnected microchannels for oil/water separation," Applied Materials Today (2017)