MOF Solar Sponge Absorbs Carbon Dioxide
February 19, 2013

CO2 Emissions Soaked Up By CSIRO ‘Solar Sponge’

Enid Burns for — Your Universe Online

A group of scientists at Commonwealth Scientific and Industrial Research Organization (CSIRO), Australia's national science agency, have created a "solar sponge" using a metal organic framework (MOF) that absorbs carbon dioxide, but releases it when exposed to sunlight.

The journal Angewandte Chemie published a paper detailing MOF.

The interaction is known as dynamic photo-switching. The capture-and-release method of dynamic photo-switching requires only UV light to trigger the release of collected CO2, which has been captured from 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 it's structure bends and twists and stored gas is released," explained Dr. Matthew Hill in a statement about the research. Hill is the team leader of the group who worked on the solar sponge and was awarded a 2012 Eureka Prize for MOF research

The MOF material has the surface area of a football field per gram. This means gases can be absorbed by the internal surfaces within the MOF to be stored until they can be safely 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," Hill said. The new method will use renewable solar energy instead of burning more fuel and releasing more carbon dioxide.

Traditionally, carbon dioxide is captured in a process that uses liquid absorbers, such as amines, to remove flue gases at coal-fired power stations before being released into the atmosphere. The liquids are then heated to release the CO2, and are then stored to repeat the process. This method requires energy -- producing more CO2 -- in order to release emissions gases. The MOF technology requires only sunlight.

Findings on MOF studies were released in a paper titled "Dynamic Photo-Switching in Metal Organic Frameworks as a Route to Low Energy Carbon Dioxide Capture and Release" that was released by CSIRO researchers. The paper explains the process that happens when MOFs are exposed to concentrated UV light where the MOF sponge instantaneously releases up to 64 percent of absorbed carbon dioxide.

Lead researcher and author of the paper, Richelle Lyndon, also a Monash University student, said in a statement, "The MOFs are impregnated with light-responsive azobenzene molecules which react to UV light and trigger the release of CO2. It is this reaction, and the material's ability to bend and flex, which makes the material we have created so unique."

If adopted, the new method of absorbing CO2 will require little to no energy, using renewable sources such as solar energy to offer cleaner air.