US scientists develop substance to absorb carbon dioxide

February 16th, 2008 - 1:55 pm ICT by admin  

Los Angeles, Feb 16 (Xinhua) US researchers have developed a substance that can absorb carbon dioxide from smokestacks and tailpipes. Researchers at the University of California in Los Angeles (UCLA) developed the gas sucker by synthesising a new class of sponge-like crystals that can soak up carbon dioxide, the primary greenhouse gas in industrial emissions, said the study published in the journal Science Friday.

The crystals, dubbed zeolitic imidazolate frameworks or ZIFs, are grids of metal atoms and organic molecules that loosely trap carbon dioxide as it drifts into microscopic pores.

The researchers believe that atomic charges hold the gas in place so that the gas could then be buried, thus preventing it from contributing to climate change.

One variety, called ZIF-69, is so absorbent that a single litre of the material can hold 83 litres of carbon dioxide, according to the study.

The crystals could be tailored to capture carbon dioxide emissions from coal-fired power plants, factories and other industrial sources, said UCLA chemist Omar Yaghi, who led the study.

The idea is to line the insides of smokestacks with a layer of ZIF. Carbon dioxide that enters the pores could be sucked out periodically and sequestered underground.

Yaghi said the material could also be used to line the exhaust systems of cars. When drivers fill their tanks with gasoline, they could also have the carbon dioxide removed.

“That is a little bit more challenging than in the power plants,” Yaghi said.
Capturing industrial carbon dioxide emissions is widely considered a key strategy for staving off global warming.

The leading method relies on a chemical reaction to trap carbon dioxide in a toxic liquid — a process deemed too expensive to implement on a commercial scale.

The US Department of Energy (DOE) has estimated that retrofitting a power plant with such a system would make electricity at least twice as expensive.

ZIFs could bring down the cost, but more testing is needed to know for sure, said Thomas Feeley, a DOE technology manager who was not involved in the research.

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