Miniature Gas Tank

January 28, 2005

Porous networks of organic Van der Waals crystals can selectively store methane and carbon dioxide

Washing powders are generally known to consist partially of inorganic zeolites. These aluminosilicates form porous structures whose cavities can act as storage for ions and molecules. In washing powders, they bind the calcium and magnesium ions that cause water to be hard. Largely unknown, however, are organic zeolites, which are also highly promising for applications such as the storage, separation, and purification of gases.

Italian researchers have now investigated such a material down to the finest detail. P. Sozzani and his co-workers from the University of Milan have confirmed the properties of crystals of the organic compound tris-o-phenylene-dioxycyclotriphosphazine. These nanoporous networks are not held together by interactions between positively and negatively charged ions like inorganic salts, but rather by much weaker Van der Waals forces.

Gases such as methane and carbon dioxide can fit into the 4.6Å wide channels in this type of open-pored, layered structure. Once in the channels, the gas molecules come into contact with the aromatic rings of the crystal by means of more Van der Waals interactions. At pressures up to 600 Torr and low temperatures of -78 °C, up to 60 % of the binding sites in the crystal are occupied by methane, and up to 100 % by carbon dioxide. At 25 °C about 15 % of the binding sites remain occupied with methane, and about 40 % with carbon dioxide.

Other gas molecules, such as hydrogen, nitrogen, oxygen, and argon cannot get into the network or are not bound by it. This high selectivity is one of the most interesting properties of the material; in this way, hydrogen could be freed from contamination by residual carbon dioxide and methane, for example. Such highly pure hydrogen is required for hydrogen-powered motors. Other applications, such as the removal of carbon dioxide from air or the storage of fuels are also conceivable.

Source: University of Milan

Explore further: Permafrost: hiding a climate time bomb?

Related Stories

Permafrost: hiding a climate time bomb?

November 20, 2015

On the front line of climate change in the Canadian Arctic, scientists hunt for clues to a potentially catastrophic global warming trend: melting permafrost.

Crack it! energy from a fossil fuel without carbon dioxide

November 19, 2015

The production of energy from natural gas without generating carbon dioxide emissions could fast become a reality, thanks to a novel technology developed by researchers of the Institute for Advanced Sustainability Studies ...

Chinese emissions to rise despite coal peak

November 18, 2015

Obscured by polluted haze, workers are putting the finishing touches to towering smokestacks on a multi-billion-dollar coal-to-oil plant in China that will pump out vast amounts of carbon dioxide when in operation.

Emissions set to soar as love of steak takes off in Asia

November 17, 2015

Climate change is the last thing on Maya Puspita Sari's mind as she tucks into a steak and splurges on ice cream, products that were once a luxury but are now a growing staple in the diets of millions of Indonesians.

Seven case studies in carbon and climate

November 13, 2015

Every part of the mosaic of Earth's surface—ocean and land, Arctic and tropics, forest and grassland—absorbs and releases carbon in a different way. Wild-card events such as massive wildfires and drought complicate the ...

Recommended for you

CERN collides heavy nuclei at new record high energy

November 25, 2015

The world's most powerful accelerator, the 27 km long Large Hadron Collider (LHC) operating at CERN in Geneva established collisions between lead nuclei, this morning, at the highest energies ever. The LHC has been colliding ...

How cells 'climb' to build fruit fly tracheas

November 25, 2015

Fruit fly windpipes are much more like human blood vessels than the entryway to human lungs. To create that intricate network, fly embryonic cells must sprout "fingers" and crawl into place. Now researchers at The Johns Hopkins ...

The hottest white dwarf in the Galaxy

November 25, 2015

Astronomers at the Universities of Tübingen and Potsdam have identified the hottest white dwarf ever discovered in our Galaxy. With a temperature of 250,000 degrees Celsius, this dying star at the outskirts of the Milky ...

A new form of real gold, almost as light as air

November 25, 2015

Researchers at ETH Zurich have created a new type of foam made of real gold. It is the lightest form ever produced of the precious metal: a thousand times lighter than its conventional form and yet it is nearly impossible ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.