The oceans contain large amounts of carbon dioxide (CO2), and now researchers from the Massachusetts Institute of Technology (MIT) have announced that they have succeeded in Direct carbon absorption They have become huge from this reserve. They claim that this method uses much less energy compared to absorbing carbon from the air and has other environmental benefits.
Is it reasonable to absorb carbon from water?
Although absorbing greenhouse gases from water may seem like a strange idea at first; But considering the huge amounts of carbon in the seas and oceans, this issue becomes very important. On the other hand, direct absorption of carbon from the air requires a lot of cost and energy, and even the most optimal current technology consumes about 6.6 gigajoules of energy, equivalent to 1.83 megawatts per hour, per ton of carbon dioxide absorption. Most of this energy is used to compress the air or provide the required temperature of the absorbent parts, and according to estimates, its cost in 2030 per ton 300 to 1000 dollars will receive.
On the other hand, no country is willing to collect a tax commensurate with the said costs from the polluting industries, and even Uruguay, which ranks first in carbon dioxide pollution tax, only receives $137 per ton. This has caused the process of carbon trapping to face a lack of funds and not enough attention. Now, researchers have come up with the idea of directly absorbing carbon from ocean water instead of air, which can solve the said problem. The surface of open water is always in contact with the air, and for this reason, it absorbs 30-40% of the carbon dioxide in the air.
Removing carbon from water can upset the balance of this substance in the oceans and cause more amounts of air to be transferred to water. It should also be taken into account that the concentration of carbon dioxide in water is 100 times higher than in air, and this can make the extraction process easier. Previous attempts to absorb carbon from water have not been very successful; Because besides the high cost, they have been permanently dependent on chemicals. Now MIT researchers have found a way that can optimally separate carbon from water with less energy consumption.
In the new system, ocean water enters two chambers, one of which has electrodes to release protons and can acidify the water. The acidification of water causes the conversion of the dissolved form of CO2 (bicarbonate) into a gaseous state, which will then be collected using suction. Finally, the water goes to the second chamber to neutralize its acidity in a reverse process so that it can be released into nature again. These steps are repeated cyclically by alternating the polarity of the electrodes, and the opposite flow of water will ensure the continuation of the reaction.
The new method currently consumes 0.77 megawatts of energy to extract each ton of carbon; But researchers hope to reduce this number even more. Also, the cost of carbon absorption has reached $56 per ton, which is significantly different from the figures related to previous methods. Of course, the cost of initial setup and some peripheral equipment is not included in this amount.
The acidification of ocean water in recent decades has caused various damages to the environment due to the accumulation of carbon in it, the most important of which is the destruction of coral reefs. Restoring the acidity of water to a normal state can help to preserve the survival of aquatic species. However, there is still a long way to go until such processes are implemented on a large scale.
