Graphene, act as a "super sieve",subatomic filter. help detoxify nuclear waste


Graphene could be used to detoxify N-waste


Graphene could be used to detoxify N-waste
The findings could revolutionise the production of the heavy water composed of a rare form of hydrogen called deuterium, which is expensive to manufacture and purify with existing technology. (Photo courtesy: Roger Ressmeyer/CORBIS)
Graphene, the thinnest and strongest substance known to science, could be used to help detoxify nuclear waste thanks to the latest discovery involving the wonder material. Experiments show that it can act as a "super sieve", able to separate different atomic isotopes of hydrogen, and create the expensive "heavy water" needed by the nuclear industry, researchers said.

This is the first time that graphene — which consists of a crystal lattice of carbon arranged in layers just one atom thick — has been shown to act as a subatomic filter.
The findings could revolutionise the production of the heavy water composed of a rare form of hydrogen called deuterium, which is expensive to manufacture and purify with existing technology.

Graphene could also be used to clean up nuclear waste contaminated with radioactive tritium, another hydrogen isotope that can be separated by the graphene filter, scientists said.

"Essentially, graphene is the finest known sieve. It can sieve particles smaller than an atom..." said Marcelo Lozada-Hidalgo of Manchester University, the first author of the study published in the journal Science.

Graphene, discovered by Nobel laureates and professors Andre Geim and Kostya Novoselov, at Manchester University in 2004, has already astonished the world of materials science with its range of unusual characteristics, such as its atomic-scale thinness, extreme strength and high electrical conductivity.

The latest study, by a research team led by professor Geim, discovered another novel property of graphene — its ability to filter the different atomic isotopes of hydrogen, namely tritium and deuterium, from ordinary hydrogen. The rare form of hydrogen, deuterium, is only present in nature in very small amounts.

The Manchester researchers showed, however, that graphene can act as a simple filter by slowing down the movement of deuterium through a membrane made of graphene and its sister material, boron nitride.

While ordinary hydrogen atoms passed straight through the sieve, deuterium was effectively blocked.

Tests showed it was possible to separate tritium and deuterium at room temperatures with high efficiency using just a fraction of the energy normally used to make heavy water. This demonstrated that the graphene filter could be used for industrial purposes, such as nuclear-waste management or the production of heavy, deuterium-rich water used as a nuclear coolant, the researchers said.

Mars Orbiter Catches a Crater Full of Cracks

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A lacy web of bright frost-filled fractures fills a crater near the north pole of Mars in this image, acquired Sept. 20, 2015 with the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter (MRO).
PHOTOS: Weirdest Mars Craters Spotted by HiRISE
The entire crater is around 3 miles (5 km) across and its ancient interior has undergone countless millennia of freeze/thaw cycles that have broken the surface into polygonal shapes. This process is common on Mars and can even be found on Earth, but this particular image depicts it exceptionally nicely.
The fractured surface polygons can be seen to get more compressed nearer to the crater’s rim. The image description by the HiRISE team explains:
The crater rim constrains the polygon formation within the crater close to the rim, creating a spoke and ring pattern of cracks. This leads to more rectangular polygons than those near the center of the crater. The polygons close to the center of the crater display a more typical pattern. A closer look shows some of these central polygons, which have smaller polygons within them, and smaller polygons within those smaller polygons, which makes for a natural fractal!
PHOTOS: NASA Spacecraft’s Epic 10 Years of Mars
A full map-projected scan of the area is below:
Polygonal terrain within and around a polar crater on Mars (monochrome red-filter HiRISE image.)
NASA/JPL-Caltech/University of Arizona
Launched Aug. 12, 2005, the MRO spacecraft has been studying the surface of Mars from orbit since March 2006. Its High-Resolution Imaging Science Experiment (HiRISE) camera, run by researchers at the University of Arizona’s Lunar and Planetary Laboratory, provides incredibly detailed images of Mars’ varied terrain in visible and near-infrared wavelengths.
PHOTOS: Mind-Blowing Beauty of Mars’ Dunes
HiRISE is capable of resolving structures on Mars’ surface down to about a meter in size from its location in orbit. The image above was acquired from a distance of 196 miles (314 km). You can see many more images from HiRISE here.


: HiRISE Photos

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