| FEATURES & INNOVATIONS |
O
ceanic oil spills are tough to clean up. They dye feathers a syrupy sepia and tan fish eggs a toxic tint. The more turbulent the waters, the farther the
slick spreads, with inky droplets descending into the briny deep. Now technology may be able to succeed
where hard-working volunteers have failed in the past. Researchers at the A*STAR Institute of Bioengineering and Nanotechnology (IBN) are using nanoscience to turn an oil spill into a floating mass of brown jelly that can be scooped up before it can make its way into the food chain.
“NANOSCIENCE MAKES IT POSSIBLE TO TAILOR THE ESSENTIAL STRUCTURES OF MATERIALS AT THE NANOMETER SCALE TO ACHIEVE SPECIFIC PROPERTIES”
“Nanoscience makes it possible to tailor
the essential structures of materials at the nanometer scale to achieve specific prop- erties,” says chemist Yugen Zhang at IBN, who is developing some of the technologies. “Structures and materials in the nanometer size range often take on distinctive properties that are not seen in other size ranges,” adds Huaqiang Zeng, another chemist at IBN.
JELLY SLICK There are many approaches to cleaning an oil spill, but none are completely effective. Fresh, thick grease can be set ablaze or contained by floating barriers for skimmers to scoop out. The slick can also be inefficiently hardened, messily absorbed, hazardously dispersed, or slowly consumed by oil-grazing bacteria. All of these are deficient on a large scale, especially in rough waters. Organic molecules with special gelling
abilities offer a cheap, simple and environ- mentally friendly alternative for cleaning up the mess. Zeng has developed several such molecules that turn crude oil into jelly within minutes.
www.astar-research.com
Yugen Zhang and Huaqiang Zeng at the A*STAR Institute of Bioengineering and Nanotechnology.
To create his ‘supergelators’, Zeng
designed the molecules to associate with each other without forming physical bonds. When sprayed on contaminated seawater, the molecules immediately bundle into long fibers between 40 and 800 nanometers wide. These threads create a web that traps the interspersed oil in a giant blob that floats on the water’s surface. The gunk can then be swiftly sieved out of the ocean. Valuable crude oil can later be reclaimed using a common technique employed by petroleum refineries called fractional distillation. Zeng tested the supergelators on four types
of crude oil with different densities, viscosities and sulfur levels in a small round dish. The results were impressive. “The supergelators solidified both freshly spilled crude oil and highly weathered crude oil 37 to 60 times their own weight,” says Zeng. The materials used to produce these organic molecules are cheap and non-toxic, which make them a commercially viable solution for managing accidents out at sea. Zeng hopes to work with industrial partners to test the nanomolecules on a much larger scale.
UNSALTY WATER Scientists at IBN are also using nanoscience to remove salt from seawater and heavy metals from contaminated water. With dwindling global fresh and ground
water reserves, many countries are looking to desalination as a viable source of drinking water. Desalination is expected to meet 30 per cent of the water demand of Singapore by 2060, which will mean tripling the country’s current desalination capacity. But desalination demands huge energy consumption and reverse osmosis, the mainstream technology it depends on, has
A*STAR RESEARCH 13
© 2016 A*STAR Institute of Bioengineering and Nanotechnology
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