With mounting anxieties about the climate crisis — particularly surrounding goals to reduce carbon emissions — action and innovation are needed now more than ever.
The Intergovernmental Panel on Climate Change has determined that greenhouse gasses must be removed from the atmosphere to reverse the rise of carbon dioxide. In other words, carbon capture is vital to limit global warming.
Between advancements in carbon sequestration and massive moves to renewable energy, we’re making global progress. But it’s still not fast enough.
Today’s carbon capture technologies, according to University of California Berkeley scientists, work well only for concentrated sources of carbon, like power plant exhaust.
They say innovations are needed to efficiently capture CO2 from the ambient air that surrounds us — where concentrations of CO2 are much lower and harder to absorb.
So, those UC Berkeley researchers set out to find a solution.
Their new research, published today in Nature, points to a new material that could help rid the air all around us of CO2.
This material — a bright yellow powder that resembles turmeric — is called a covalent organic framework. It is made from a porous material that captures carbon dioxide from ambient air.
“We took a powder of this material, put it in a tube, and we passed Berkeley air — just outdoor air — into the material to see how it would perform,” Omar Yaghi, a chemistry professor and senior author of the latest research, said in a statement.
“It was beautiful. It cleaned the air entirely of CO2. Everything.”
These results are groundbreaking. Yaghi said the new material could be easily integrated into carbon capture systems already deployed to remove CO2 from refinery emissions or to capture atmospheric carbon and store it underground.
“I’m excited about it because there’s nothing like it out there in terms of performance,” Yaghi added. “It breaks new ground in our efforts to address the climate problem.”
The scientists say that just 200 grams of the material can absorb up to 20 kilograms of carbon in a year — which is approximately the same absorption potential as a tree.
Graduate student Zihui Zhou also worked on the research and said that capturing “flue gas,” or the mixture of gasses that exists in the atmosphere, is a “way to slow down climate change.”
“Direct air capture is a method to take us back to like it was 100 or more years ago,” Zhou said.
Currently, CO2 emissions are 50% higher than they were prior to the industrial revolution.
While this exciting development is especially timely, Yaghi and fellow researchers have been developing this material for the past 20 years.
Yaghi is the inventor of covalent- and metal-organic frameworks: these crystalline, porous structures that provide a surface area for gasses to stick to or be absorbed.
His lab created a promising version of what is now their groundbreaking discovery two years ago, but after hundreds of cycles of absorption, it unfortunately kept breaking down.
Their work was cut out for them: Understand why MOFs degrade when capturing gasses from the air.
“Trapping CO2 from air is a very challenging problem,” Yaghi said. “It’s [energy] demanding, you need a material that has high carbon dioxide capacity, that’s highly selective, that’s water stable, oxidatively stable, recyclable. It needs to have a low regeneration temperature and needs to be scalable. It’s a tall order for a material.”
Eventually, working with colleagues in Germany and Chicago, Yaghi and his team designed a stronger material, named COF-999. The framework is held together by covalent carbon-carbon and carbon-nitrogen double bonds (instead of metals), which are among the strongest chemical bonds in nature.
Now, their material can withstand contaminants from acids and bases, to water, sulfur, and nitrogen, all while still successfully capturing carbon from the air.
“This COF has a strong chemically and thermally stable backbone, it requires less energy, and we have shown it can withstand 100 cycles with no loss of capacity,” Yaghi said.
“No other material has been shown to perform like that. It’s basically the best material out there for direct air capture.”
Now, the researchers hope to use artificial intelligence to speed up the design of even better carbon capture materials — the kind that can be deployed to help tangibly address the impacts of climate change.
Header image courtesy of Zihui Zhou, UC Berkeley
