Two different types of nanostructures have been reported as nanotech methods to clean up oil spills and other organic pollutants. Researchers at MIT have developed a nanowire mesh that can reversibly absorb 20 times it weigh in oil. Researchers at Rice have shown how specially designed “nanobatons” can trap oil droplets by spontaneously assembling into sacs. From MIT News, written by Elizabeth A. Thomson “MIT develops a ‘paper towel’ for oil spills” (via PhysOrg.com):
Nanowire mesh can absorb up to 20 times its weight in oil
A mat of nanowires with the touch and feel of paper could be an important new tool in the cleanup of oil and other organic pollutants, MIT researchers and colleagues report in the May 30 online issue of Nature Nanotechnology [abstract].
The scientists say they have created a membrane that can absorb up to 20 times its weight in oil, and can be recycled many times for future use. The oil itself can also be recovered. Some 200,000 tons of oil have already been spilled at sea since the start of the decade.
“What we found is that we can make ‘paper’ from an interwoven mesh of nanowires that is able to selectively absorb hydrophobic liquids—oil-like liquids—from water,” said Francesco Stellacci, an associate professor in the Department of Materials Science and Engineering and leader of the work.
In addition to its environmental applications, the nanowire paper could also impact filtering and the purification of water, said Jing Kong, an assistant professor of electrical engineering in the Department of Electrical Engineering and Computer Science and one of Stellacci’s colleagues on the work. She noted that it could also be inexpensive to produce because the nanowires of which it is composed can be fabricated in larger quantities than other nanomaterials.
From Rice University, via AAAS EurekAlert “Nanoparticles assemble by millions to encase oil drops“
Designer ‘nanobatons’ could be used to trap oil, deliver drugs
In a development that could lead to new technologies for cleaning up oil spills and polluted groundwater, scientists at Rice University have shown how tiny, stick-shaped particles of metal and carbon can trap oil droplets in water by spontaneously assembling into bag-like sacs.
The tiny particles were found to assemble spontaneously by the tens of millions into spherical sacs as large as BB pellets around droplets of oil in water. In addition, the scientists found that ultraviolet light and magnetic fields could be used to flip the nanoparticles, causing the bags to instantly turn inside out and release their cargo — a feature that could ultimately be handy for delivering drugs.
“The core of the nanotechnology revolution lies in designing inorganic nanoparticles that can self-assemble into larger structures like a ‘smart dust’ that performs different functions in the world — for example, cleaning up pollution,” said lead research Pulickel Ajayan, Rice’s Benjamin M. and Mary Greenwood Anderson Professor in Mechanical Engineering and Materials Science. “Our approach brings the concept of self-assembling, functional nanomaterials one step closer to reality.”
The research was published online today by the American Chemical Society’s journal Nano Letters [abstract].
The multisegmented nanowires, akin to “nanoscale batons,” were made by connecting two nanomaterials with different properties, much like an eraser is attached to the end of a wooden pencil. In the study, the researchers started with carbon nanotubes — hollow tubes of pure carbon. Atop the nanotubes, they added short segments of gold. Ajayan said that by adding various other segments — like sections of nickel or other materials — the researchers can create truly multifunctional nanostructures.