Facilely Grafting Small Amine Molecules into Co-Exchanged Zeolite for Enhancing CO₂ Adsorption

Zeolites are promising materials for CO2 adsorption, yet they still face the challenges of low adsorption capacity and selectivity. Herein, we report a strategy of grafting ethylenediamine to a Co-exchanged Y zeolite to improve the CO2 adsorption capacity of Y zeolite via strong interactions between Co2+ and amine groups. Functionalization of zeolite Y with amines (Co-Y-EN) enables significant improvement in the CO2 adsorption capacity (4.36 mmol/g at 1 bar and 298 K), which is 1.73 times higher than that of pristine Na-Y zeolite. Moreover, Co-Y-EN demonstrates enhanced CO2 selectivity, as confirmed by both single-component gas adsorption experiments and breakthrough tests. The superior selectivity is attributed to the strong affinity between the amine sites and CO2 molecules, as well as the optimized pore sizes for CO2 adsorption. Overall, this study presents a straightforward approach to enhancing the CO2 adsorption performance of zeolite materials.