Georgia Tech Pioneers New Method for Extracting Carbon Dioxide

To help reduce global warming, researchers at Georgia Institute of Technology’s School of Chemical and Biomolecular Engineering (ChBE) have developed a method for capturing carbon dioxide (CO₂) from the atmosphere.

Although direct air capture (DAC) technologies have emerged over the past decade, high capital and energy costs have limited their large-scale use.

In this study, the team demonstrated a way to capture CO₂ more efficiently and at lower cost. They used very cold air and widely available porous sorbent materials, which could improve the feasibility of future DAC systems.

Harnessing Already Available Energy

The research team included members from Jeonbuk National University and Chonnam National University in South Korea, as well as Oak Ridge National Laboratory in Tennessee. They combined DAC with the regasification of liquefied natural gas (LNG), a common industrial process that produces very cold temperatures.

LNG is natural gas that has been cooled into a liquid for transport. Before use, it must be reheated into a gas. This process often uses seawater as a heat source, which wastes the cold energy stored in the LNG.

Instead, the Georgia Tech team used this cold energy to create better conditions for CO₂ capture. They cooled the air using materials called “physisorbents”—porous solids that physically absorb gases.

Most current DAC systems use amine-based materials that chemically bind CO₂. These materials have limited pore space, degrade over time, and require a large amount of energy to operate efficiently. Physisorbents, by contrast, offer longer lifespans and faster CO₂ uptake. However, their performance declines in warm, humid conditions.

The study showed that when air is cooled to near-cryogenic temperatures, almost all water vapor condenses out. This reduces humidity and allows physisorbents to capture more CO₂ without the need for energy-intensive water removal steps.

This is an exciting step forward. We’re showing that you can capture carbon at low costs using existing infrastructure and safe, low-cost materials.

Ryan Lively, Thomas C. DeLoach Professor, School of Chemical and Biomolecular Engineering, Georgia Institute of Technology

Cost and Energy Savings

According to economic modeling by Lively’s team, integrating the LNG-based approach into DAC could reduce the cost of capturing one metric ton of CO₂ to as low as $70. This is about three times lower than current DAC methods, which often exceed $200 per ton.

Through simulations and experiments, the researchers identified Zeolite 13X and CALF-20 as the most effective physisorbents for this process. CALF-20 is a metal-organic framework (MOF) known for its stability and ability to capture CO₂ from flue gas, though it is less studied for air capture. Zeolite 13X is a cost-effective, durable desiccant commonly used in water treatment.

At –78 °C, a typical operating temperature for the LNG-DAC system, both materials showed CO₂ adsorption capacities about three times higher than those of amine-based materials at room temperature. They also released the captured CO₂ with minimal energy input, making them promising for practical use.

Beyond their high CO₂ capacities, both physisorbents exhibit critical characteristics such as low desorption enthalpy, cost efficiency, scalability, and long-term stability, all of which are essential for real-world applications.

Seo-Yul Kim, Study Lead Author and Postdoctoral Researcher, Georgia Institute of Technology

Leveraging Existing Infrastructure

The study also addresses a key consideration for DAC: location. Traditional systems perform best in dry, cool climates. However, by using existing LNG infrastructure, near-cryogenic DAC could be applied in temperate or humid coastal areas. This would significantly expand the range of locations suitable for carbon removal.

“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,” stated Lively.

The study also addresses a key consideration for DAC: location. Traditional systems perform best in dry, cool climates. However, by using existing LNG infrastructure, near-cryogenic DAC could be applied in temperate or humid coastal areas. This would significantly expand the range of locations suitable for carbon removal.

“This is an exciting example of how rethinking energy flows in our existing infrastructure can lead to low-cost reductions in carbon footprint,” added Lively.

The study also found that a broader range of materials can be used for DAC at lower temperatures. At ambient temperatures, only a limited number of materials are effective. Near-cryogenic conditions significantly increase the number of viable options.

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.

Matthew Realff, Study Co-Author and Professor, School of Chemical and Biomolecular Engineering, Georgia Institute of Technology

Journal Reference:

Kim, S.-Y., et al. (2025). Near-cryogenic direct air capture using adsorbents. Energy & Environmental Science. doi.org/10.1039/D5EE01473E.