Exploring a Novel Adsorbent for CO₂ Capture and Gas Separation.

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Growing need for effective carbon capture technologies to mitigate carbon emissions.
• Small-pore zeolites are promising solid adsorbents for CO2 capture in postcombustion and biogas separation.
• Levyne (LEV-type) zeolite remains largely unexplored for CO2 adsorption applications.

Purpose of the Study:

• To investigate levyne (LEV-type) zeolite as a novel adsorbent for CO2 capture and gas separation.
• To synthesize and characterize nanosized and micron-sized LEV zeolites.
• To evaluate the impact of synthesis conditions, Si/Al ratio, and particle size on CO2 adsorption and separation performance.

Main Methods:

• Seed-assisted synthesis of LEV zeolites under varying conditions.
• Characterization of synthesized zeolites (morphology, crystal size, chemical composition).
• Dynamic adsorption measurements using breakthrough curve analysis and in situ FTIR spectroscopy.

Main Results:

• Micron-sized LEV (Si/Al=3.5, high Na+ content) demonstrated superior CO2 uptake and selectivity over nanosized LEV (Si/Al=6.6).
• Micron-sized LEV exhibited twice the CO2 adsorption capacity and higher CO2/N2 and CO2/CH4 selectivities compared to nanosized LEV.
• FTIR analysis indicated both physisorption and chemisorption of CO2 in micron-sized LEV, versus predominantly physisorption in nanosized LEV.

Conclusions:

• Synthesis strategies significantly influence LEV zeolite properties for gas separation.
• LEV zeolites, particularly micron-sized with optimized Si/Al ratios, are promising physical adsorbents for CO2 capture.
• Controlling zeolite framework composition and cation content is crucial for enhancing CO2 adsorption and separation.