Influence of cation exchange on the selective CO2 adsorption performance of Zeolite-Y over CH4 and N2

Abstract

Carbon dioxide capture from a post-combustion process is challenging and henceforth adsorbents with high adsorption capacities are required. For such applications, cation-loaded zeolites offer significant carbon dioxide capture potential. In this article, the cations (Li⁺, Na⁺, and K⁺) were loaded onto Zeolite-Y with the wet-impregnation method and the synthesized adsorbents were characterized using FTIR, XRD, BET, FETEM, and XPS, and were analyzed with the gravimetric adsorption system. The effect of cation, pressure, and temperature was particularly targeted and assessed. Accordingly, for a 5 wt% cation loading, the CO₂ adsorption capacity reduced from 2.89 to 0.79 mmol g⁻¹ for the temperature alteration from 303 to 343 K, highlighting the impact of temperature on adsorption performance for the synthesized adsorbents. The adsorption data was analyzed with two distinct modeling approaches for the visualization of the adsorption behavior. Additionally, the Ideal Adsorbed Solution Theory (IAST) has been applied to determine the selectivity of the cation-loaded zeolites for CO₂ with respect to other gases. The analysis provided valuable insights into the adsorbents’ potential for gas separation applications. Among the synthesized adsorbents, KYZC with 10 wt% potassium loading exhibited the highest CO₂ adsorption capacity of 2.89 mmol g⁻¹ at 303 K and 1 bar, which was higher than NaYZC (2.74 mmol g⁻¹), LiYZC (2.37 mmol g⁻¹), and HYZC (2.19 mmol g⁻¹). KYZC also demonstrated superior selectivity for CO₂/CH₄ (219.59) and CO₂/N₂ (140.62) gas mixtures compared to the other adsorbents, highlighting its potential for gas separation applications. The study confirmed that the Zeolite-Y was loaded with alkali metal cations and has been effective for carbon dioxide capture. Adsorbents for CO₂ capture in real-world industrial processes have been developed with the mentioned simple yet effective methodology.