The porous chemcial material made of melamine can effectively capture CO2 in flue gas

Today, although energy intensive, the dominant method of carbon dioxide capture and storage is the industrial emission of bubbles through liquid amines. MOFs and other porous chemical materials have good prospects and higher energy efficiency. Now, researchers have found a cheaper and equally effective carbon dioxide capture chemical material: porous melamine networks. As the main component of bakelite, melamine has lower regeneration cost than other alternatives and can be used to capture carbon dioxide from automobile exhaust.

Using a cheap polymer called melamine, the main component of bakelite, chemists have created a cheap, simple and energy-saving way to capture carbon dioxide from chimneys, a key goal of the United States and other countries seeking to reduce greenhouse gas emissions.

The process of synthesizing melamine materials, published in the journal science advances this week, may be scaled down to capture emissions from automobile exhaust or other mobile carbon dioxide sources. The carbon dioxide produced by fossil fuel combustion accounts for about 75% of the greenhouse gas produced in the United States

This new chemical material is simple to make, and mainly needs melamine powder on the market – the price of this powder is about $40 per ton today – as well as formaldehyde and melamine acid. One of the other uses of melamine acid is to add it to swimming pools together with chlorine.

“We want a carbon capture material, which is very cheap and easy to obtain. So we decided to start with melamine,” said Jeffrey Reimer, a professor at the Graduate School of Chemical and Biomolecular Engineering at the University of California, Berkeley, and one of the corresponding authors of the paper.

The efficiency of the so-called melamine porous network to capture carbon dioxide is comparable to the early results of another relatively new carbon capture material, metal organic frameworks (MOFs). Chemists at the University of California, Berkeley, created the first such carbon capture MOF in 2015, and later versions proved to be more effective in removing carbon dioxide from flue gases (such as coal-fired power plants).

However, Mao Haiyan, the first author of the paper and a postdoctoral fellow at the University of California, Berkeley, said that melamine based materials use cheaper raw materials, are easier to make, and are more energy-saving than most MOFs. The low cost of porous melamine means that the chemical material can be widely used.

“In this study, we focused on the design of cheaper capture and storage materials and clarified the interaction mechanism between carbon dioxide and materials,” Mao said. “This work has created a general industrial method to achieve sustainable carbon dioxide capture using porous networks. We hope that we can design an accessory for capturing automobile exhaust, or a coating for building accessories, or even furniture surfaces.”

The study was conducted by a team at the University of California, Berkeley, led by Raymer; The research team led by Cui Yi, director of the precourt Energy Research Institute of Stanford University, visiting professor somorjai Miller of the University of California, Berkeley, and former Postdoctoral Fellow of the University of California, Berkeley; Alexander pine, Professor, Graduate School, University of California, Berkeley; And a group led by Hong Cai Zhou of Texas A & M University. Tang Jing, a postdoctoral fellow of Stanford University and Stanford Linear Accelerator Center, is a visiting scholar of the University of California, Berkeley. Together with Mao, he is the first author.

Carbon neutrality in 2050

Although the elimination of fossil fuel combustion is crucial to curbing climate change, an important interim strategy is to capture the emissions of carbon dioxide (the main greenhouse gas) and store it underground or convert it into usable products. The US Department of energy has announced a project with a total amount of 3.18 billion US dollars to promote advanced and commercially scalable carbon capture, utilization and storage (CCUs) technology to achieve the ambitious goal of 90% carbon dioxide capture efficiency in flue gas. The ultimate goal of the United States is to achieve zero carbon emissions by 2050.

But carbon capture technology is far from commercially viable. The best technology today is to pipe the flue gas through the liquid amine, which can bind carbon dioxide. But it requires a lot of energy to release the carbon dioxide bound to the amine so that it can be concentrated and stored underground. The amine mixture must be heated to 120 – 150 degrees Celsius (250 – 300 degrees Fahrenheit) to regenerate carbon dioxide.

In contrast, the melamine porous network modified with deta and melamine acid captured carbon dioxide at about 40 ° C, slightly higher than room temperature, and released at 80 ° C, lower than the boiling point of water. The energy saved comes from the fact that the material does not need to be heated to a high temperature.
In their research, the Berkeley / Stanford / Texas team focused on the common polymer melamine, which is not only used for bakelite, but also for cheap tableware and tableware, industrial coatings and other plastics. Treating melamine powder with formaldehyde – which researchers measured in kilograms – creates nanoscale pores in the melamine that researchers believe can absorb carbon dioxide.

Mao said that the test confirmed that formaldehyde treated melamine has a certain adsorption effect on carbon dioxide, but adding another amine-containing chemical substance deta (diethylenetriamine) to combine with carbon dioxide can greatly improve the adsorption effect. She and her colleagues later found that adding trimeric acid to the polymerization reaction would significantly increase the pore size and fundamentally improve the carbon dioxide capture efficiency: almost all carbon dioxide in the simulated flue gas mixture was absorbed within about 3 minutes.

The addition of trimeric acid also makes this material reusable.

The research shows that the trimeric acid forms a strong hydrogen bond with the melamine network, which helps to stabilize deta and prevent it from leaching from the melamine pores in the repeated cycle of carbon capture and regeneration.

“Haiyan and her colleagues can use these elegant technologies to show how these groups are mixed and how carbon dioxide reacts with them. In the presence of this kind of open-ended trimeric acid, she can cycle carbon dioxide repeatedly with very good ability.” “Compared with other materials, the carbon dioxide adsorption rate is actually quite fast. Therefore, all practical aspects of the carbon dioxide capture material in the laboratory scale have been satisfied, and it is very cheap and easy to manufacture.”

“By using solid-state NMR technology, we have systematically elucidated the mechanism of the reaction between amorphous networks and carbon dioxide in unprecedented and atomic details,” Mao said. “For the energy and environmental communities, this work creates a family of high-performance solid-state networks and a thorough understanding of the mechanism, but also encourages the evolution of porous material research from trial and error methods to rational, step-by-step, atomic level modulation.”

Reimer and Cui’s team are continuing to adjust the pore size and amine groups to improve the carbon capture efficiency of the melamine porous network while maintaining energy efficiency. This involves using a technology called dynamic combinatorial chemistry to change the proportion of components to achieve efficient, scalable, recyclable and high-capacity carbon dioxide capture.

Reimer specially developed solid-state NMR to characterize the mechanism of interaction between solid materials and carbon dioxide, so as to design better materials to capture carbon from the environment and store energy. Cui has developed a powerful and sustainable solid-state platform and manufacturing technology for manufacturing new materials to cope with climate change and energy storage.