An FGDG Functionalized Composite with Enhanced CO2 Adsorption Performance: Facile Fabrication, Kinetics, and Adsorption Isotherm

Mixtures of shell-biochar and calcium silicate slag were firstly impregnated with pentaethylenehexamine, and then were mixed with wet flue gas desulfurization gypsum (FGDG) particles to prepare the adsorbents. The results showed that the crystalline water in FGDG slags changed the CO2 adsorption mechanisms of the amine groups, and the FGDG modified adsorbents exhibited a comparable cyclic recyclability and the adsorption capacity only decreased by 3.61% up to 12 adsorption/desorption cycles. The crystalline water contained in FGDG is successfully supported on the surfaces of the adsorbent. The adsorbent loaded with 35% of FGDG exhibits a higher adsorption capacity than the adsorbent without FGDG, suggesting that the crystalline water promotes the CO2 adsorption performances. It demonstrates a favorable recyclability because its saturated adsorption capacity reduced by 3.61% after twelve adsorption-desorption cycles.