Novel salt-based strategy may efficiently capture and store carbon dioxide

"Our team made it possible to carry CO2 in a solid form without the need for refrigeration or pressure."
Mrigakshi Dixit
Aerial view of a coal fired power station.
Aerial view of a coal fired power station.


With the rising greenhouse gas emissions, it has become inevitable to develop cutting-edge solutions to remove the lingering carbon dioxide from the Earth's atmosphere. 

To address this urgent global crisis, an international team of researchers has developed a promising strategy to store and capture carbon dioxide (CO2). 

They developed a guanidinium sulfate salt-based method for carbon capture and storage at room temperature and pressure. Scientists used this salt to make "lattice-like structures" called clathrates, which enabled the capturing of CO2 molecules. 

"The guanidinium sulfate serves to organize and trap the CO2 molecules without reacting with them. We have discovered a rare example of a clathrate that is stable and non-corrosive at ambient temperature and pressure, a highly desirable feature compared with ethanol amine, ammonia, and other solutions that are commonly used in carbon capture,” explained Cafer Yavuz, professor of chemistry, and director of the KAUST Oxide and Organic Nanomaterials for Energy & Environment (ONE) Laboratory, in an official statement

The salt-based, clathrate technique allows for quick CO2 solidification, making it easier to store. Conventionally, CO2 is stored as a solid in the form of dry ice in gas cylinders or as mineral carbonates. In contrast, the clathrate method felicitates the CO2 to be stored as a solid powder. 

"Our team made it possible to carry CO2 in a solid form without the need for refrigeration or pressure. You will be able to literally shovel CO2-loaded solids from now on. The impact is wide and strong, as the global fuel industry and the Kingdom entities are actively looking for ways to capture, store and transport CO2 without significant energy penalties," said Yavuz. 

The new method is considered energy-efficient as the entire process requires little energy input. Furthermore, the salt-based strategy is less expensive than large, bulky machines that capture this global warming gas. 

In the future, this novel method of capturing, transporting, and storing carbon dioxide could be a game changer for many industries.

Various universities conducted this new study; the Southern University of Science and Technology, the University of Science and Technology of China, and the King Abdullah University of Science and Technology. 

The results have been reported in the journal Cell Reports Physical Science.

Study abstract:

Reversible CO2 capture and release under ambient conditions is crucial for energy-efficient carbon capture and storage. Here, we report the pressure swing crystallization of CO2 in a single-crystalline guanidinium sulfate-based clathrate salt under practical conditions of 52 kPa and 298 K, with a high CO2 density (0.252 g cm−3) and capacity (17 wt %). The captured CO2 is released as a pure stream through moderate means of pressure or temperature stimulation, all while the desorbed Gua2SO4 is ready for another cycle. The clathrate is selective exclusively to CO2 even in the presence of common flue gas components, such as water vapor and N2, owing to the specific electrostatic interaction between the CO2 and guanidinium cations. The mechanism unraveled through single-crystal studies is distinctively different from physisorption or chemisorption, opening up a promising venue for future carbon capture and storage technologies through rapid CO2 solidification using an abundant salt.

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