Dynamic CO2 separation performance of nano-sized CHA zeolites under multi-component gas mixtures

To identify and evaluate promising adsorbents for CO2 separation, we synthesized CHA zeolites with different cations (Na+, K+, Cs+) and crystal sizes (45 nm - CHA45 and 500 nm - CHA500), and evaluated their explored CO2 adsorption performance from CO2/N2/He and CO2/CH4/He mixtures. Grand Canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations predicted CO2, N2, and CH4 adsorption isotherms and CO2 mobilities, respectively, which were compared to experimental data. Breakthrough curve analysis was used to assess the CO2 dynamic adsorption performance. The breakthrough curve analysis shows the smaller crystal sizes (45 nm) enhance the CO2 separation due to shorter interacrystalline diffusion pathways. Notably, Cs-CHA45 removed 2.2 times more CO2 from CO2/N2/He than Cs-CHA500. K-CHA45 showed the highest CO2/N2 selectivity (108) and achieved 841mmol g- 1 for CO2 capture from N2 and 721mmol g- 1 for CO2 from CH4. These findings underscore the potential of CHA nanocrystals for effective CO2 separation in various applications.