Metals supercharge promising method to bury harmful carbon dioxide under
the sea

Date:
September 22, 2021
Source:
University of Texas at Austin
Summary:
Researchers have found a way to supercharge the formation of
carbon dioxide-based crystal structures that could someday store
billions of tons of carbon under the ocean floor for centuries,
if not forever.



FULL STORY ========================================================================== There's a global race to reduce the amount of harmful gases in our
atmosphere to slow down the pace of climate change, and one way to do
that is through carbon capture and sequestration -- sucking carbon out
of the air and burying it. At this point, however, we're capturing only a fraction of the carbon needed to make any kind of dent in climate change.


========================================================================== Researchers from The University of Texas at Austin, in partnership
with ExxonMobil, have made a new discovery that may go a long way in
changing that.

They have found a way to supercharge the formation of carbon dioxide-based crystal structures that could someday store billions of tons of carbon
under the ocean floor for centuries, if not forever.

"I consider carbon capture as insurance for the planet," said
Vaibhav Bahadur (VB), an associate professor in the Cockrell School of Engineering's Walker Department of Mechanical Engineering and the lead
author of a new paper on the research in ACS Sustainable Chemistry & Engineering. "It's not enough anymore to be carbon neutral, we need to
be carbon negative to undo damage that has been done to the environment
over the past several decades." These structures, known as hydrates,
form when carbon dioxide is mixed with water at high pressure and low temperature. The water molecules re-orient themselves and act as cages
that trap CO2 molecules.

But the process initiates very slowly -- it can take hours or even days
to get the reaction started. The research team found that by adding
magnesium to the reaction, hydrates formed 3,000 times faster than the
quickest method in use today, as rapidly as one minute. This is the
fastest hydrate formation pace ever documented.

"The state-of-the-art method today is to use chemicals to promote the reaction," Bahadur said. "It works, but it's slower, and these chemicals
are expensive and not environmentally friendly." The hydrates form in reactors. In practice, these reactors could be deployed to the ocean
floor. Using existing carbon capture technology, CO2 would be plucked
from the air and taken to the underwater reactors where the hydrates
would grow. The stability of these hydrates reduces the threat of leaks
present in other methods of carbon storage, such as injecting it as a
gas into abandoned gas wells.

Figuring out how to reduce carbon in the atmosphere is about as big of a problem as there is in the world right now. And yet, Bahadur says, there
are only a few research groups in the world looking at CO2 hydrates as
a potential carbon storage option.

"We are only capturing about half of a percent of the amount of carbon
that we'll need to by 2050," Bahadur said. "This tells me there is plenty
of room for more options in the bucket of technologies to capture and
store carbon." Bahadur has been working on hydrate research since
he arrived at UT Austin in 2013. This project is part of a research
partnership between ExxonMobil and the Energy Institute at UT Austin.

The researchers and ExxonMobil have filed a patent application to
commercialize their discovery. Up next, they plan to tackle issues
of efficiency - - increasing the amount of CO2 that is converted into
hydrates during the reaction -- and establishing continuous production
of hydrates.

The research was funded by ExxonMobil and a grant from the National
Science Foundation. Bahadur led the team, which also includes Filippo Mangolini, an assistant professor in the Walker Department of Mechanical Engineering. Other team members include: from the Walker Department of Mechanical Engineering Aritra Kar, Palash Vadiraj Acharya and Awan Bhati;
from Texas Materials Institute at UT Austin Hugo Celio and researchers
from ExxonMobil.

========================================================================== Story Source: Materials provided by University_of_Texas_at_Austin. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Aritra Kar, Palash Vadiraj Acharya, Awan Bhati, Ashish Mhadeshwar,
Pradeep Venkataraman, Timothy A. Barckholtz, Hugo Celio, Filippo
Mangolini, Vaibhav Bahadur. Magnesium-Promoted Rapid Nucleation of
Carbon Dioxide Hydrates. ACS Sustainable Chemistry & Engineering,
2021; 9 (33): 11137 DOI: 10.1021/acssuschemeng.1c03041 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/09/210922155849.htm

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