Crystals can absorb CO2
UCLA scientists have synthesized a new class of sponge-like 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 UCLA chemist Omar M. 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 vehicle exhaust systems. When drivers fill their gas tanks, they could also have the carbon dioxide removed.
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 would at least double the cost of generating electricity.
--
