Canadian researchers have developed a way of quickly producing the mineral magnesite, which forms through the spontaneous absorption of carbon dioxide from the atmosphere at room temperature. Such a material might be a boon in "scrubbing" exhaust fumes of the greenhouse gas. Ian Power of Trent University, Ontario, and colleagues hope that one day their approach might be taken up to the industrial scale to make it possible to remediate atmospheric CO2 levels.
Actively removing carbon dioxide from the atmosphere might be one way to reduce the potentially devastating effects of rising levels of the gas due to human activity, such as burning fossil fuels. Materials that absorb the gas could be one solution that at sufficient scale might lead be viable for scrubbing flues or even in geoengineering. One naturally occurring material, magnesite, can remove around half a ton of carbon dioxide from the atmosphere per ton of mineral. However, the rate of formation is very slow.
Speaking at the Goldschmidt Conference in Boston this year, Power explains that "Our work shows two things. First, we have explained how and how fast magnesite forms naturally." Natural magnesite crystallization at low temperatures has been known for many years but remained unexplained in the weathering of ultramafic rocks, such as peridotite. This is a process which takes hundreds to thousands of years in nature at Earth's surface. "The second thing we have done is to demonstrate a pathway which speeds this process up dramatically," adds Power.
The researchers used polystyrene microspheres as a catalyst, to accelerate the rate of magnesite formation to within 72 days. The microspheres are essentially unchanged by the process and can be used again. Using microspheres means that the team could speed up magnesite formation by several orders of magnitude. "This process takes place at room temperature, meaning that magnesite production is extremely energy efficient," Power adds.
At the moment, the process is simply a proof of principle. It works only at the laboratory scale at the moment, but the team hopes that the process could be scaled up for carbon sequestration technologies. Of course, the production of the microspheres and the requisite industrial plants, transport and storage facilities would have to be offset against the carbon dioxide they themselves would generate to make the approach to carbon sequestration worthwhile. Regardless, Power points out that we now know that the science makes it do-able.
David Bradley blogs at Sciencebase Science Blog and tweets @sciencebase. His popular science book Deceived Wisdom is now available.