New crystals can absorb CO2, study finds

Chemist says process could be applied to emissions from coal plants

Scientists at the University of California, Los Angeles, have synthesized a class of spongelike crystals that can soak up carbon dioxide, the primary greenhouse gas in industrial emissions.

The crystals – 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.

One variety, ZIF-69, is so absorbent that a single liter of the material can hold 83 liters of carbon dioxide, according to a study published Friday in the journal Science.

The crystals could be tailored to capture carbon dioxide emissions from coal-fired power plants, factories and other industrial sources, said Omar M. Yaghi, the chemist from UCLA 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 also could be used to line vehicle exhaust systems. When drivers fill their gas tanks, they also could have the carbon dioxide removed.

“That is a little bit more challenging than in the power plants,” he said.

Capturing industrial carbon dioxide emissions is 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 U.S. Department of Energy has estimated that retrofitting a power plant with such a system at least would double the cost of generating electricity.

More testing is needed to determine if ZIFs can reduce the cost, said Thomas Feeley, a DOE technology manager who was not involved in the research.