US researchers develop ultra-efficient carbon capture material

Researchers in the US have developed an advanced material that they claim could help dramatically improve the efficiency of carbon capture and storage processes.

The material, developed by a team at the University of California, Berkeley, is able to remove carbon dioxide from the atmosphere at a range of different temperatures and then release it at lower temperatures than current carbon-capture materials.

According to Prof Jeffrey Long, who is heading up the work, the material could potentially reduce the energy required by the process by more than fifty per cent and could enable significant reductions in size.

“Carbon dioxide is 15 per cent of the gas coming off a power plant, so a carbon-capture unit is going to be big,” he said in a statement. “With these new materials, that unit could be much smaller, making the capital costs drop tremendously as well as the operating costs.”

The diamine-appended metal-organic framework before and after binding of carbon dioxide.
The diamine-appended metal-organic framework before and after binding of carbon dioxide.

The material, which is described in Nature, is a metal-organic framework (MOF) modified with nitrogen compounds called diamines, and can be tuned to remove carbon dioxide from the room-temperature air of a submarine, for example, or the 100-degree (Fahrenheit) flue gases from a power plant.

The development builds on earlier work carried out by Long’s team, where it developed a way to attach amines to the metals in an MOF to produce pores of sufficient diameter to allow CO2 to penetrate rapidly into the material.

The group found that MOFs with attached diamines are very different from other carbon-capture materials, in that the CO2 seems to load into the material very quickly at a specific temperature and pressure, then come out quickly when the temperature is raised by 50oC.

“This material is unique in that it binds CO2 in a cooperative mechanism,” Long said. “When the first CO2 starts to adsorb at a very specific pressure, all of a sudden it facilitates more CO2 adsorption, and the MOF rapidly saturates. That is really a different property from any other CO2 adsorbent based on amines.

Long has co-founded a startup, Mosaic Materials, to use the new technology to radically reduce the cost of chemical separations, with plans in the works for a pilot study of CO2 separation from power plant emissions.

This would involve creating columns containing millimeter-size pellets made by compressing a crystalline powder of MOFs.He also hopes to develop a device that could be tested in a submarine, and that would pave the way for eventual scale-up to capturing CO2 from natural gas plants. 

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