Promoting the regeneration of polyethylenimine‐impregnated sorbents through in situ vapor purge for direct air capture
Yongqiang Wang, Qiuran Yang, Paul Webley, Guoping Hu, Gang Kevin LiAbstract
Amine‐impregnated sorbents (AIS) have been extensively investigated for direct air capture (DAC) due to their high adsorption capacity and selectivity toward atmospheric CO 2 . However, there has been limited attention given to efficiently recovering the adsorbed CO 2 from AIS, leading to the regeneration remaining energy‐intensive in DAC systems. Here, we employ a double‐layered adsorption configuration, in situ producing vapors using water synergistically harvested from the air to effectively regenerate polyethylenimine‐impregnated sorbents. This vapor‐promoted regeneration provided a substantial driving force for CO 2 desorption at ambient pressure and 105°C, producing water and 99% purity CO 2 with a high working capacity of 1.61 mmol/g. Only 8.9 MJ/ thermal energy was consumed for sorbent regeneration without the use of vacuum conditions and external purge. This in situ vapor purge enables the recovery of over 95% of the CO 2 adsorbed on AIS, paving the way for the practical application of low‐cost chemisorbents in DAC.