New adsorbent captures CO₂ from air and withstands high temperatures

A research team from the Korea Institute of Energy Research (KIER) has successfully developed a new solid adsorbent capable of directly capturing CO₂ from the atmosphere and recovering it at an average high purity of 96.5%. The team, led by Dr. Young Cheol Park also succeeded in demonstrating the recovery of more than 1 kilogram of CO₂ per day, bringing the technology one step closer to commercialization.

The concentration of CO₂ in the atmosphere in Korea first exceeded 400 PPM in 2013 and continued to rise, reaching 427 PPM in 2023. During the same period, the country’s average annual temperature increased by 1.1°C, highlighting the severity of the climate crisis caused by global warming.

Carbon capture technology has already been widely developed and applied to major CO₂-emitting facilities such as power plants and factories. However, reducing dispersed CO₂ in the atmosphere requires new technological approaches. This is why Direct Air Capture (DAC) technology, which directly removes CO₂ from the air, is gaining attention.

DAC technology primarily utilizes amine-based solid adsorbents, which have the selective property of capturing only CO₂. The process works by allowing the adsorbent to capture CO₂ from the air and then exposing it to high temperatures above 100°C to release the captured CO₂, enabling the recovery of high-concentrated CO₂.

However, amine-based adsorbents have a drawback—their durability decreases at high temperatures, leading to reduced performance. To address this issue, alternative technologies, such as recovering CO₂ in a vacuum environment, have been explored. However, these alternatives have yet to reach commercialization.

The research team developed a new amine-based solid adsorbent (SMKIER-1) to address the durability issues of conventional adsorbents in high-temperature environments.

Conventional adsorbents consist of amines which strongly capture CO₂, and a silica support that holds the amines in place. However, the strong bond between CO₂ and the amines requires a significant amount of thermal energy to break. During this process, the amines, which have low heat resistance, are easily damaged, leading to performance degradation.

To address this issue, the research team added a cyclic compound-type additive to the amine. This additive not only reduces the binding strength with carbon dioxide but also protects the amine, preventing heat-induced damage. As a result, the energy required for carbon dioxide capture and recovery is reduced, while high-purity carbon dioxide can be stably recovered even in high-temperature environments exceeding 100°C.

The research team applied the developed adsorbent to the process and conducted a continuous operation demonstration for over 350 hours. As a result, they successfully recovered 1 kilogram of carbon dioxide per day at a high purity of 96.5%, marking the first reported case of its kind in the country.

The research team plans to conduct a demonstration of a process capable of capturing 10 kilograms of carbon dioxide per day this year. Moving forward, they aim to gradually scale up the process to a capacity of 200 kilograms per day, with the goal of securing commercialization technology by 2030. Through this effort, they anticipate establishing a demonstration facility capable of capturing over 1,000 tons of carbon dioxide annually by 2035.

Dr. Young Cheol Park, the lead researcher, stated, “With this technology, we have taken the first step toward a solution that could ultimately reduce millions of tons of carbon dioxide annually in our country.” He added, “This achievement will make a significant contribution to the global efforts toward carbon neutrality.”