An innovative process converts CO2 into solid and durable materials that retain carbon.
Scientists have created in the United States a sustainable, negative carbon construction material using seawater, electricity and carbon dioxide (CO2).
The material, which eliminates more CO2 than emits, retaining up to more than half of its weight in CO2, can be used in concrete as a substitute for sand (which enters 70% of concrete composition) or in cement, plaster and paint manufacturenot weakening cement resistance or concrete.
In a statement, the in the United States, who led the work, also points out that The process to generate the material with negative carbon also releases hydrogena clean fuel with various applications, namely in transport, which can help in combating
A process inspired by the technique that mollusks use to form their shells
In a reactor, scientists began by inserting electrodes into seawater and applying an electric current. The low electric current separated the water molecules in hydrogen and hydroxide ions.
Keeping the electric current, the investigators injetaram CO2 in seawater, whose chemical composition has changed with this process, increasing the concentration of bicarbonate ions.
Hydroxide and bicarbonate ions reacted with other dissolved ions, such as calcium and magnesium, which naturally exist in seawater and The reaction produced solid minerals such as calcium carbonate and magnesium hydroxide.
Calcium carbonate acts directly as a carbon sink, while magnesium hydroxide kidnaps carbon through posterior interactions with CO2.
The method used was inspired by the technique that mollusks use to form their shellstaking advantage of metabolic energy to convert dissolved ions into calcium carbonate.
Instead of metabolic energy, scientists applied electricity to initiate the process and boosted mineralization with CO2 injection.
A material that can be denser or more porous
In experiences done, the investigators team not only it achieved transform calcium carbonate and magnesium hydroxide into sandbut also change the composition of the new material through the control of variables, such as voltage and electric current, the duration of CO2 injection or seawater recirculation in the reactor.
Depending on the conditions, The resulting material can be more porous or denser and harderbut is always composed of calcium carbonate and/or magnesium hydroxide.
According to the authors of the study, released in the scientific publication control of the properties of the new material during the production process, such as the chemical composition, size, shape and porosity, It gives “some flexibility” to create materials “suitable for different applications”.
The work has resulted from a partnership between Northwestern University and Cemex, a construction material company based in Mexico, and dedicated to the development of sustainable solutions, representing the United States.
