Cold Temperatures and Common Materials: A Low-Cost Method for Removing CO2 from the Atmosphere

Researchers at Georgia Tech have developed a method to remove CO2 from the air using cold temperatures and common materials, expanding deployment opportunities for direct air capture. By combining DAC with liquefied natural gas regasification, they created a superior environment for capturing CO2 using physisorbents, which offer longer lifespans and faster CO2 uptake. This approach could reduce the cost of capturing one metric ton of CO2 to as low as $70, a threefold decrease from current costs.

Researchers at Georgia Tech have made a significant breakthrough in the field of carbon dioxide (CO₂) removal from the atmosphere. By combining direct air capture (DAC) with liquefied natural gas (LNG) regasification, they have developed a method that utilizes extremely cold air and common porous sorbent materials, known as physisorbents. This approach promises to expand the deployment opportunities for DAC and significantly reduce the cost of capturing CO₂.

The research, published in Energy & Environmental Science, demonstrates techniques for capturing CO₂ more efficiently and affordably. The team, which includes members from Oak Ridge National Laboratory in Tennessee and universities in South Korea, employed a method that harnesses the cold energy from LNG to chill the air, creating an optimal environment for CO₂ capture. This method is particularly promising as it leverages existing industrial infrastructure and safe, low-cost materials.

Physisorbents, which are porous solids that soak up gases, offer several advantages over the amine-based materials commonly used in DAC today. They provide longer lifespans and faster CO₂ uptake, but have historically struggled in warm, humid conditions. The Georgia Tech study showed that cooling the air to near-cryogenic temperatures for DAC enables physisorbents to achieve higher CO₂ capture performance without the need for expensive water-removal steps.

The economic modeling conducted by the research team suggests that integrating this LNG-based approach into DAC could reduce the cost of capturing one metric ton of CO₂ to as low as $70, approximately a threefold decrease from current DAC methods, which often exceed $200 per ton. The study identified Zeolite 13X and CALF-20 as leading physisorbents for this DAC process. These materials showed strong CO₂ adsorption at -78°C with capacities approximately three times higher than those found in amine materials that operate at ambient conditions.

The study also addresses a key concern for DAC: location. Traditional systems are often best suited for dry, cool environments. However, by leveraging existing LNG infrastructure, near-cryogenic DAC could be deployed in temperate and even humid coastal regions, greatly expanding the geographic scope of carbon removal. According to Professor Ryan Lively of ChBE@GT, "LNG regasification systems are currently an untapped source of cold energy, with terminals operating at a large scale in coastal areas around the world. By harnessing even just a portion of their cold energy, we could potentially capture over 100 million metric tons of CO₂ per year by 2050."

As governments and industries face increasing pressure to meet net-zero emissions goals, solutions like LNG-coupled near-cryogenic DAC offer a promising path forward. The next steps for the team include continued refinement of materials and system designs to ensure performance and durability at larger scales.

The research demonstrates that an expanded range of materials could be employed for DAC. While only a small subset of materials can be used at ambient temperatures, the number that are viable grows substantially at near-cryogenic temperatures. According to Professor Matthew Realff, co-author of the study and professor at ChBE@GT, "Many physisorbents that were previously dismissed for DAC suddenly become viable when you drop the temperature. This unlocks a whole new design space for carbon capture materials."

References:
[1] https://www.chbe.gatech.edu/news/2025/07/study-demonstrates-low-cost-method-remove-co2-air-using-cold-temperatures-common
[2] https://www.datacenterdynamics.com/en/news/microsoft-pilots-use-of-data-center-waste-heat-to-power-direct-air-capture-systems/
[3] https://techxplore.com/news/2025-07-method-air-cold-temperatures-common.html