Fast and selective separation of carbon dioxide from dilute streams by pressure swing adsorption using solid ionic...

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Economically viable carbon capture is crucial for mitigating climate change.
• Physisorption using selective sorbents offers a promising approach.
• Solid Ionic Liquids (SoILs) present tunable properties suitable for operational conditions.

Purpose of the Study:

• To design and synthesize novel Solid Ionic Liquids (SoILs) for selective carbon dioxide (CO₂) capture.
• To evaluate the performance of acetate-based SoILs for CO₂ sorption.
• To assess the economic viability and process implications of using SoILs.

Main Methods:

• Molecular modelling was employed to identify candidate SoIL materials.
• Synthesis of selected acetate anion-based SoILs.
• Experimental evaluation of CO₂ capture selectivity, capacity, and cycling rates under pressure swing conditions (1-10 bar).

Main Results:

• Selected SoILs demonstrated excellent CO₂ selectivity over nitrogen and oxygen.
• Sorption and desorption cycles occurred rapidly, within seconds.
• Moderate sorption capacity was observed.
• Concentrated CO₂ was isolated via pressure release.

Conclusions:

• The rapid sorption cycling rate is more critical than capacity for low-concentration CO₂ capture.
• SoILs enable smaller process equipment and reduced sorbent inventories.
• Low volatility and thermal stability of SoILs contribute to reduced plant and material costs.