A new melamine-based material for carbon dioxide sequestration

Hello dear friends.

Global warming continues at an accelerated pace due to our dependence on fossil fuels to supply the energy we need for our mobility and lifestyle, which only increases the concentration of greenhouse gases in the atmosphere, especially carbon dioxide emissions, which has had the environmental repercussions we already know. That is why many organizations have set a global goal of carbon neutrality by 2050, which seems very difficult if we do not prevent more carbon dioxide from reaching the atmosphere. Now, thanks to a very inexpensive polymer called melanin, a group of chemists have developed a cheap and energy-efficient way to capture carbon dioxide at the point of generation.

New melamine-based material could be used to capture CO2. Source: Image edited at Poerpoint, original from Pixabay.com.

Aqueous polyamines have been widely investigated in this field of development, due to their ease of spontaneous CO₂ fixation and their low cost. However, they have presented important disadvantages, such as decomposition into volatile amines and the amount of energy required to regenerate the solvent, in addition to other problems that have arisen from their use, such as corrosion of lines and equipment, and the generation of emissions that are hazardous to people's health.

Among the proposals made to solve these limitations of polyamines and improve their applicability in carbon capture is the use of amine-functionalized adsorbents instead of using aqueous polyamines, since this would avoid the generation of hazardous and corrosive substances without affecting the selectivity of amines for CO₂.

Now, although amine functionalization with metal-organic frameworks have demonstrated high adsorption capacity, there is great interest in developing porous adsorbents based on polymers, since they can be synthesized without the presence of metals, which makes them more economical and sustainable, characteristics highly desired for mass production.

Therefore, a team of researchers, mainly from Berkeley and Stanford Universities, has been working on the production of a solid-state melamine nanoporous network (MNNs), with added polyamines and stabilized with cyanuric acid, to achieve more efficient, high-capacity and scalable CO₂ capture. The results of their research were recently published in the journal Sciences Advances.

This new material is very easy to produce, as it basically requires melamine powder, an aminoresin that is the main component of the adhesive used to make chipboard and formica, which is widely available on the market, and is also very cheap, while formaldehyde and cyanuric acid are also affordable chemicals, the latter even being added as a stabilizer for chlorine in swimming pools.

Melamine structure. Source: wikipedia.org.

By treating melamine powder with formaldehyde they were able to create nanoscale pores that allowed the melamine to adsorb some CO₂, but by adding diethylenetriamine (DETA), another amine-containing substance, they were able to improve adsorption on this material. Subsequently, it was found that adding cyanuric acid during the polymerization reaction greatly increased the pore size and adsorption of CO₂, finding that a simulated combustion mixture was adsorbed almost completely in a short time.

The DETA-modified MNNs structure acts as a CO2 capture network. Source: Powerpoint image.

Adsorption isotherms were measured at 298K with CO₂ as the carrier gas, finding that the coordination of polyamine and cyanuric acid provides the porous network with a high adsorption capacity, registering 1.82 millimoles per gram at 1 bar, in an adsorption time of less than 1 minute, representing an extraordinary stability to flue gas cycling.

On the other hand, the porous melamine lattice modified with DETA and cyanuric acid achieved CO₂ capture capture at 40 °C, and achieved its release from the lattice at 80 °C, considerably low temperatures that represent considerable lower energy consumption compared to other amine systems where the mixture must be heated to approximately 150 °C to release the CO₂ and regenerate the adsorbent.

Llet's hope that this research continues to progress and that new techniques are developed for the manufacture of economical and sustainable materials to address on a larger scale the problem of global warming due to CO₂ emissions.

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Thanks for coming by to read friends, I hope you liked the information. See you next time.

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