Capturing Carbon Dioxide with a "Solar Sponge"
A new smart material called a MOF (metal organic framework) has the ability to adsorb carbon dioxide and release it when exposed to sunlight thus creating a new breakthrough in a way to recycle CO2 emissions using renewable energy.
The process is known as dynamic photo-switching which refers to the reversible light-induced switching of floor or intensity. This capture-and-release method is extremely energy efficient and only requires UV light to trigger the release of CO2 after it has been captured from the mixture of exhaust gases.
Dr Matthew Hill was awarded a 2012 Eureka Prize for his MOF research and led Australia's national science agency, CSIRO, in conducting the research.
Dr Hill explains the process: "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."
"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.
Capturing carbon dioxide is important especially from large point sources like fossil fuel power plants because it prevents the greenhouse gas from entering the atmosphere and contributing to global warming and ocean acidification. One way to capture this compound is by using liquid absorbers such as amines to remove flue gases at coal-fired power station before they are released into the atmosphere. They are then heated to release the CO2 which is then stored and can be re-used. This process is not very efficient and can consume as a much as 30 per cent of a power plant's production capacity.
MOF technology on the other hand is shown to absorb as much as a litre 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, allowing gases to be soaked up by all of the internal surfaces within. When exposed to concentrated UV light the MOF sponge instantaneously releases up to 64 per cent of absorbed CO2.
Dr Hill concludes: "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."
The paper titled 'Dynamic Photo-Switching in Metal Organic Frameworks as a Route to Low Energy Carbon Dioxide Capture and Release' can be found in the scientific journal Angewandte Chemie.
See more at CSIRO.
Sponge image via Shutterstock.