Researchers from the University of Texas at Austin are developing a technology that they hope can speed up the rate that the deep sea stores carbon.
Oceans absorb roughly 30 per cent of the carbon dioxide that is released by humans and can keep the captured carbon stored away for hundreds of years. However, this natural process takes time and scientists say that there could be a way to speed this up.
There are two main mechanisms that oceans use to capture this greenhouse gas. Carbon dioxide dissolves into the oceans and forms carbonic acid, hydrogen ions, and bicarbonate ions. Some of this carbon is transported to great depths by ocean currents, whereas other carbon is ingested by microorganisms like phytoplankton that eventually die and sink down to the ocean floor.
The University of Texas researchers are working in partnership with ExxonMobil and say that their aim is to increase the amount of carbon that can be sucked out of the atmosphere to prevent the Earth from warming to dangerously high levels.
The researchers mixed carbon dioxide with water at high pressure and low temperature, which causes the water molecules to change their structure and “act as cages” that trap carbon dioxide. The resulting structure is called a hydrate and takes several hours or days to form in the ocean.
Carbon dixoide hydrates in a test tube. (University of Texas at Austin/ ExxonMobil)
Magnesium was added to boost this process and the researchers found that this addition caused the hydrates to form as fast as one minute, which is 3,000 times faster than the quickest method that scientists are currently using. The team states that this is the fastest hydrate formation pace that has ever been documented.
"The state-of-the-art method today is to use chemicals to promote the reaction," Vaibhav Bahadur, an associate professor in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering, said in the university’s press release.
"It works, but it’s slower, and these chemicals are expensive and not environmentally friendly."
The hydrates are created in reactors and the team says that they could potentially be placed on the seafloor. According to the press release, the researchers and ExxonMobil have filed a patent application so they can one day commercialize their technology.
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