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If you've been keeping up with the latest developments in
technology, then you've probably heard about at least one new development stemming
from nanotechnology. The ability to control matter on the molecular scale has
opened up a new door that is brimming with possibilities. Nanotech allows for
the creation of new materials with unique and enhanced properties, and has specific
implications for the electronics and biomedical industries.
One of the latest nanotech discoveries came through
researchers at Rice University and Penn State. They found that adding boron to
carbon during nanotube construction creates spongy blocks that have amazing oil
absorbing properties.
(Image Credit: Rice University - Jeff Fitlow -->)
How It Works
The typical chemical vapor deposition process which grows multiwalled
carbon nanotubes on a substrate usually produces straight tubes with no
interconnections. But adding boron introduces defects into the nanotubes by
encouraging carbon to form covalent bonds at the atomic level, resulting in a
tangled and complex network of tubes. In short, adding boron puts kinks and
elbows into the otherwise straight carbon tubes.
From this:
(Image Credit: redOrbit)
To This:
(Image Credit: Elsevier)
To add boron, scientists use very high temperatures in a furnace, essentially 'knitting' the substance to the nanotube fabric in a one step process. The result is a
material with a very low density and large available volume for capturing and
holding oils.
Nanosponges have been created
before, but the processes used to induce the unique structure were always
post-growth, meaning they were done after the nanotubes were already formed.
The use of boron allows the tubes to form proper covalent connections during
their creation.
What It Does
The nanosponge is extremely hydrophobic, giving it the
natural tendency to float on water and not absorb it even when submerged. It is
also ferromagnetic, meaning it can be controlled or retrieved using a magnet.
The density of the material is extremely low, making the available volume for
oil uptake very high. Not only can it soak up over 100 times its weight in oil
as it floats on the water, but it can store the oil for later retrieval. The
oil can then be squeezed out or burned off, allowing the sponge to be reused. The
researchers also tested the sponge's robustness and reusability in the lab - it
maintained elasticity even after 10,000 compressions. Safe to say, this
material has tremendous power as an agent for surface oil cleanup.
This
video from Rice University gives a visual demonstration of the material's
properties.
What It Means
The process used to create the sponge is the perhaps real
success story here. The main drawback with past nanosponges was their inability
to be produced on a large scale. With this one-step formation process,
production of the material can be scaled up to bigger production quantities
much more easily. The next step for researchers is in finding ways to create
the large sheets needed for oil spill applications.
Of course, what it all comes down to is cost effectiveness.
Can these nanosponges eventually be made cheap enough to complete or displace
other oil cleaning technologies and methods? And will their oil-cleaning properties
be useful enough in real-life oil spill problems, where a lot of the oil
collects underneath the surface of the water.
What's interesting is that, like many new technologies, this
product may have other potential applications besides environmental cleanup. Researchers
say it could be used for making lighter and more efficient batteries, scaffolds
for bone-tissue regeneration, composites for the automotive and aerospace
industries, or membranes for filtration. It is a testament to the versatility
of materials developed at the nanoscale.
Source
RICE
University - Nanosponges soak up oil again and again
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