Novel CO2 Adsorbent Prepared with ZSM-5/MCM-48 as Support: High Adsorption Property and Its Mechanism

• Novel amino-bifunctionalized ZSM-5/MCM-48 adsorbent achieves a high CO2 adsorption capacity of 5.82 mmol·g–1 at 60 °C in 15% CO2. • The combination of APTES grafting and TEPA/PEI impregnation synergistically enhances adsorption performance and amine efficiency. • Chemical adsorption dominates via CO2-amino group reactions, forming carbamate, alkyl ammonium carbamate, and carbonate, with weak physical adsorption. • The composites show outstanding potential for CO2 capture from flue gas after desulfurization.