AsianScientist (Feb. 18, 2013) – Coal power station emissions could be reduced by a new, energy-efficient material that adsorbs carbon dioxide, then releases it when exposed to sunlight.
A new study published in Angewandte Chemie presents a new way to recycle carbon dioxide emissions using a ‘sponge’ which is made from a new smart material called a metal organic framework (MOF). The material has an exceptional ability to store carbon dioxide, but when exposed to sunlight, instantaneously releases it.
Known as dynamic photo-switching, this capture-and-release method is extremely energy efficient and only requires UV light to trigger the release of carbon dioxide after it has been captured from the mixture of exhaust gases.
“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.
“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.
Traditionally, carbon dioxide capture has been performed using liquid absorbers such as amines to remove flue gases at a coal-fired power station. The absorbers are then heated to release the carbon dioxide which is then stored and can be re-used. This process can consume as a much as 30 percent of a power plant’s production capacity.
MOFs, however, absorb as much as a liter of nitrogen gas in just one gram of material. This is possible because MOFs have the surface area of a football field in just one gram, meaning that gases can be soaked up like a sponge to all of the internal surfaces within.
When exposed to concentrated UV light, the MOF sponge instantaneously releases up to 64 percent of absorbed carbon dioxide.
“The MOFs are impregnated with light-responsive azobenzene molecules which react to UV light and trigger the release of carbon dioxide. It is this reaction, and the material’s ability to bend and flex, which makes the material we have created so unique,” said lead author Richelle Lyndon, who is also a Monash University student.