Amine-functionalized hierarchically porous monolithic adsorbent for carbon dioxide capture in humidity flue gas

For efficient and low-energy CO 2 capture, developing adsorbents with stable performance is of paramount importance. In this study, a hierarchically porous monolithic solid amine adsorbent was successfully prepared. Amines are uniformly immobilized in the mesopores of this structure, while the macropores provide pathways for CO 2 mass transfer, thus endowing the adsorbent with both high adsorption capacity and fast adsorption kinetics. The CO 2 adsorption capacity of the 50 T-MS adsorbent reaches 137.2 mg g −1 under dry condition. Moreover, it remains as high as 137.0 mg g −1 after 50 adsorption-desorption cycles under 100% relative humidity, demonstrating favorable cyclic stability. Further research reveals that appropriate humidity not only enhances CO 2 adsorption capacity and reduces regeneration energy consumption, but also improves long-term stability by inhibiting the formation of urea by-products.