Researchers from the School of Chemical & Biomolecular Engineering (ChBE) at Georgia Institute of Technology have published a groundbreaking study in Energy & Environmental Science, demonstrating a new method that uses ultra-cold air and widely available porous adsorbent materials to remove carbon dioxide (CO₂) from the atmosphere more efficiently and economically—offering a fresh approach to mitigating global warming.

Over the past decade, although direct air capture (DAC) has shown promise, high capital and energy costs have hindered large-scale deployment. In this study, the team developed an innovative approach that integrates DAC with liquefied natural gas (LNG) regasification. The regasification process generates extremely low temperatures, and this cryogenic energy is traditionally wasted by heating with seawater. The Georgia Tech researchers cleverly harness this cold energy to cool the air, creating conditions far more favorable for CO₂ capture.

The team employed physical adsorbents—porous solid materials that, compared to the amine-based materials commonly used in current DAC systems, offer longer lifetimes, faster CO₂ uptake rates, and significantly higher capture performance at low temperatures without requiring costly water removal steps. Through simulation and experimentation, the team identified zeolite 13X and CALF-20 as the primary physical adsorbents for this LNG-DAC process. At -78°C (typical for the LNG-DAC system), these materials exhibit strong CO₂ adsorption capacity—approximately three times that of conventional amine materials at ambient temperature—and can release captured and purified CO₂ with much lower energy input.

Economic modeling shows that integrating this LNG-based approach into DAC can reduce the cost of capturing one metric ton of CO₂ to as low as $70—roughly one-third of current DAC methods (typically over $200 per ton). This cost advantage makes the technology highly practical for real-world application.

The study also addresses DAC deployment locations. Traditional DAC systems perform best in dry, cool environments, but by leveraging existing LNG infrastructure, near-cryogenic DAC can be deployed in temperate or even humid coastal regions, dramatically expanding the geographic scope for carbon removal. Estimates suggest that even utilizing only a portion of the cold energy from large-scale LNG regasification facilities along global coastlines could enable the capture of more than 100 million metric tons of CO₂ annually by 2050.

As governments and industries face mounting pressure to achieve net-zero targets, solutions like LNG-coupled near-cryogenic DAC offer a highly promising path forward. The team's next steps will focus on continuous improvement of materials and system design to ensure performance and durability at larger scales.

The research also reveals that the range of materials usable for DAC is far broader than previously thought. Many physical adsorbents previously excluded from DAC due to poor performance at ambient temperature become viable once the temperature is lowered, opening an entirely new design space for carbon-capture materials.

"This is an exciting example of how rethinking energy flows in our existing infrastructure can dramatically reduce carbon footprints at low cost," said Professor Ryan Lively from ChBE@GT.