Crystallization method offers new option for carbon capture from ambient air

Scientists at the Department of Energy’s Oak Ridge National Laboratory (ORNL) including Radu Custelcean, an MSU Chemistry Ph.D. graduate from Professor Ned Jackson’s group in 2000, have found a simple, reliable process to capture carbon dioxide directly from ambient air, offering a new option for carbon capture and storage strategies to help combat global warming. 

In the process, they discovered a method to capture and release carbon dioxide that requires minimal energy and chemical input. Their results are published in the journal Angewandte Chemie International Edition. 

“When we left an aqueous solution of the guanidine open to air, beautiful prism-like crystals started to form,” ORNL’s Radu Custelcean said. “After analyzing their structure by X-ray diffraction, we were surprised to find the crystals contained carbonate, which forms when carbon dioxide from air reacts with water.”

“Through our process, we were able to release the bound carbon dioxide by heating the crystals at 80-120 °C, which is relatively mild when compared with current methods,” Dr. Custelcean said. After heating, the crystals reverted to the original guanidine material. The recovered compound was recycled through three consecutive carbon capture and release cycles. 

While the direct air capture method is gaining traction, according to Custelcean, the process needs to be further developed and aggressively implemented to be effective in combatting global warming.

The study titled, “CO2 Capture from Ambient Air by Crystallization with a Guanidine Sorbent,” included Charles Seipp of ORNL and the University of Texas at Austin; Neil Williams of ORNL and the University of Tennessee; and ORNL’s Michelle Kidder and Radu Custelcean.