Polyallylamine and NaOH as a novel binder to pelletize amine-functionalized mesoporous silicas for CO2 capture

A binder solution containing polyallylamine (PAA) and NaOH is proposed to construct pellets from powdered amine-functionalized mesoporous silica, thereby providing active sites for CO2 capture. Various powdered amine-functionalized adsorbents were prepared and pelletized, including 3-aminopropyl-triethoxysilane-functionalized MCM-41 obtained through post-modification and direct synthesis, and polyethylenimine-loaded MCM-41 obtained through impregnation. The effects of the concentrations of FAA and NaOH on the strength, durability, and CO2 adsorption capacity of the pellets were evaluated, as the anhydrous and humid CO2 adsorption behavior and cyclic thermal stability. The pellets prepared after mixing the powdered adsorbents with an aqueous solution of 3 wt% FAA and 2 wt% NaOH exhibited the CO2 adsorption capacity slightly lower than the powdered adsorbent, a recovery of greater than 90% of the powdered adsorbents was observed, while their mechanical strength was over 0.4 MPa and the weight could be retained over 90% in durability tests. Moreover, the pelletized adsorbents possessed the high thermal stability in cyclic adsorption/desorption. As a result, the proposed binder formula can be used to provide pelletized amine-functionalized adsorbents for CO2 capture from power plants. (C) 2014 Elsevier Inc. All rights reserved.