Zeolite monoliths with hierarchical designed pore network structure: Synthesis and performance

Structured adsorbents with attractive characteristics have been developed for use in CO2 capture applications. 5A zeolite monolithic structures with a hierarchical designed channel/pore system and high zeolite content approaching 92 wt% were prepared. The body of the monoliths contained three different sizes of channels and pores; macro, meso and micro. The developed monoliths showed outstanding performance on CO2 separation from CO2/N2 gas mixtures compared to commercial 5A beads. The equilibrium isotherms of pure gas adsorption were collected, CO2/N2 binary gas breakthrough experiments were conducted, and pressure drop along beds packed with the monoliths or 5A beads was measured. The experimental data were simulated and the results showed that effective diffusivity was six times higher and pressure drop was 1.3 times lower for 5A monolith bed compared to 5A beads bed. The high effective diffusivity, low pressure drop and comparable adsorption capacity of the prepared 5A monoliths indicate that they are ideal candidates for rapid pressure swing adsorption applications.