MIT researchers have developed a system that could reverse the process of ocean acidification caused by human activity.
As carbon dioxide continues to build up in Earth’s atmosphere, researchers and industry have spent years looking for ways to effectively remove it from the air. However, the oceans are the most important sinks of CO2 present in the air, absorbing 30 to 40% of all the gas produced by human activities. This natural process, however, has a significant impact on marine ecosystems, as it increasingly acidifies seawater.
A less polluting method than atmospheric capture techniques
Recently, the possibility of extracting carbon dioxide directly from the oceans has emerged as a promising option to mitigate CO2 emissions.2. This solution could even lead one day to net negative emissions at the global level. However, it has not yet led to large-scale application, because existing methods require specific membranes and a constant supply of chemicals, which makes the processes complex and expensive.
It’s a drawback that a team of researchers from MIT may have solved. Led by Professors T. Alan Hatton and Kripa Varanas, they developed a device that would require none of these elements and even consume less energy than airborne capture techniques.
The method involves passing seawater through two different chambers. In the first chamber, it is acidified by electrodes which inject protons into it, releasing carbon dioxide which is then extracted for storage. The water is then introduced into the second chamber, where it becomes alkaline again (ie it is no longer acidic) thanks to a set of cells which recover the previously added protons. She is then returned to the ocean.
Many possible applications
The researchers suggest that re-injection of alkaline water could be done through devices scattered or far from shore to avoid local alkalinity spikes that could disrupt ecosystems, such as coral reefs, that are already weakened. ” We will not be able to treat all of the planet’s emissions “says Mr. Varanasi. However, this re-injection could be in places such as fish farms, which directly contribute to the acidification of the water.
It would also be possible to combine these devices with infrastructures that already treat seawater, such as desalination plants. Mr. Varanasi explains: “ This system is scalable, so we could potentially integrate it into existing processes. In this case, carbon dioxide removal could be a simple addition to facilities that already return large amounts of water to the oceans.
Finally, it would also be possible to equip freight ships with them, which would contribute to deacidifying the oceans in a more global and dispersed way, while actively reducing their carbon impact.
Source : ScienceDaily
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