Hey there!
My name’s Amanda Maceda and I’m an undergraduate Chemistry major and Geoscience minor at the
University of Texas at Dallas.
Today I’d love to talk to you about a new idea on how to remove some of the excess carbon
dioxide from our environment.
Even if we transition to renewable energy sources by mid-century, our atmosphere will
still bear an overload of CO2 from more than 200 years of industry-scale fossil fuel burning.
According to the Intergovernmental Panel on Climate Change, its estimated that we need
to remove over 10 gigatons of carbon dioxide from our atmosphere annually in order to curb
catastrophic rises in temperature by mid-century.
If we’re able to accomplish that, global temperature is only predicted to rise by 2
degrees centigrade by 2050.
So, let’s talk about a truly “down to Earth” method to reduce atmospheric CO2
and avert global warming.
Whenever it rains, carbon dioxide in the air combines with water to produce carbonic acid,
H2CO3.
This weak acid falls to the ground where it slowly breaks down the minerals in rocks,
releasing calcium, magnesium, and iron ions.
These ions are dissolved and carried down to streams and rivers that flow into the ocean.
Once in the ocean, these positively charged ions combine with negatively charged bicarbonate
ions, “kicking out” the hydrogen and inserting themself in its place.
This final product is a solid carbonate mineral.
By this reaction, carbon dioxide is both removed from the atmosphere and converted into an
inert solid.
In the oceans, calcium carbonates become a material for seashell formation.
Carbonate mineralization can also happen on land, especially in deserts where carbonates
often form in soils, making caliche.
Some well-known carbonate minerals include calcite, magnesite, and siderite, and are
commonly used in fertilizers and construction.
It’s estimated that 0.1 gigatons of carbon dioxide is captured annually through this
process - thus it would take thousands of years to offset current anthropogenic emissions
as carbonate mineralization naturally functions.
But the urgency to clean up our air before it’s too late is encouraging chemists and
geologists to figure out how to speed up this process.
One approach is to capture and convert carbon dioxide emitted from fossil fuel burning to
make carbonate materials for construction, such as bricks.
It’s estimated that doing this could capture 1 gigaton of carbon dioxide annually.
A recent project in Iceland, called Carbfix, is advancing this process inland.
Initially, over 200 tons of carbon dioxide was collected from a nearby powerplant, dissolved
in water, and then injected underground into a site of basalt.
Basalt is a common volcanic rock which contains olivine and plagioclase, minerals shown to
be especially reactive with carbon dioxide.
The pores and fractures of basalts at this depth underground provides additional surface
area for minerals to react with carbon dioxide and precipitate carbonates.
Up to 95% of the injected carbon dioxide mineralized in under 2 years.
Since then, this process continues to be used for emissions at the Hellishiedi geothermal
power plant, but there are plans to expand and test an offshore version in the coming
years.
With better understanding of this mechanism, alongside other technologies, the future looks
bright and cool.
Thank you so much for watching!