Ultrasonic‐Swing Carbon Dioxide Release Using Aralkylamines for Direct Air Capture

Direct air capture (DAC) is a promising approach for removing CO 2 from ambient air, but the energy required for CO 2 release from sorbents remains a major challenge. In this study, we investigated ultrasonic‐assisted CO 2 release using aralkylamines containing aromatic moieties, with the aim of expanding the library of regeneration methods available for DAC systems. The aralkylamines underwent solidification after CO 2 absorption, enabling rapid CO 2 desorption under ultrasonic irradiation. Compared with previously reported ultrasonic‐assisted CO 2 release systems based on monoethanolamine, the present system exhibited faster CO 2 liberation, suggesting that the solid‐state characteristics of the CO 2 ‐loaded amines contributed to enhanced desorption. In addition, cyclic absorption–desorption experiments demonstrated that the CO 2 recovery capacity was maintained over four consecutive cycles. These results indicate that aralkylamine‐based phase‐changing sorbents combined with ultrasonic stimulation provide a promising strategy for CO 2 regeneration under mild, low‐temperature conditions in DAC processes.