When your ice tea overflows the cup, forming a puddle on the counter, how do you clean it up? A sponge of course. Now scientists are working to see if the same idea will work with all that excess carbon dioxide that’s swirling around in our atmosphere.
Researchers at Australia’s national science agency, CSIRO, are developing a smart material called a MOF (metal organic framework) that could make it possible to capture C02 without using further coal-based energy. Using only the power of sunlight, these ‘solar sponges’ could be a new way to recycle carbon emissions without creating more in the process.
Traditionally, carbon dioxide capture has been accomplished through the use of liquid absorbers to catch flue gases at a coal-fired power plant before they escape into the atmosphere. The gases must then be heated to release the CO2 which is then stored and can be re-used. While slightly better than letting pollutants fly free, this process can consume as a much as 30 percent of a power plant’s production capacity. Not exactly efficient, especially when talking about power from fossil fuels.
In comparison, the CSIRO team uses a process called dynamic photo-switching, which refers to the reversible light-induced switching of floor or intensity. Instead of using liquid absorbers, the team used MOFs to absorb as much as a liter of nitrogen gas in just one gram of material. The unique material only requires UV light to trigger the release of CO2 after it has been captured from the mixture of exhaust gases. When exposed to concentrated UV light the MOF sponge instantaneously releases up to 64 percent of absorbed CO2, which can then be recycled into usable fuel.
“The capture and release process can be compared to soaking up water with a sponge and then wringing it out. When UV light hits the material its structure bends and twists and stored gas is released,” said Dr Matthew Hill, who was awarded a 2012 Eureka Prize for his MOF research and led the CSIRO group conducting this research. ”This is an exciting development for carbon capture because concentrated solar energy can be used instead of further coal-based energy to drive the process,” he added.
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