Zeolites as Selective Adsorbents for CO₂ Separation

Zeolites are a very versatile class of materials that can display selective CO2 adsorption behavior and thus find applications in carbon capture, storage, and utilization (CCSU). In this contribution, the properties of zeolites as CO2 adsorbents are reviewed by critically presenting and discussing their assets and limitations. For this purpose, we first provide an overview of the CO2 adsorption mechanisms on different types of zeolites. Then, we systematically discuss the relationship between the physicochemical properties of zeolites (framework type, Si/Al ratio, and extra-framework cations) and their performance as CO2 adsorbents for the separation of CO2/CH4 (biogas) and CO2/N2 (flue gas) mixtures. Based on the trends and properties identified, we provide a comparison of the different zeolites and highlight their advantages and drawbacks for applicability in CO2 adsorption. Finally, we present the state of the art in the shaping of zeolites in macroscopic format, which is a key step toward their industrial utilization as adsorbents.