Advanced Solid Amine Adsorbents with Exceptional Oxidative Stability for Efficient Capture of Low-concentration CO₂

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Developing effective solid amine adsorbents for capturing trace carbon dioxide (CO2) is crucial.
• Existing adsorbents often struggle with a balance between high CO2 adsorption capacity and oxidative stability.
• Urea formation and metal-catalyzed oxidation are key challenges limiting adsorbent performance.

Purpose of the Study:

• To introduce an innovative solid adsorbent, ED-PEI/PEG@FS-TBP, designed for enhanced CO2 capture.
• To improve the oxidative stability and CO2 adsorption capacity of solid amine adsorbents.
• To address the limitations of urea formation and metal-catalyzed oxidation in CO2 capture materials.

Main Methods:

• Functionalization of polyethyleneimine (PEI) with 1,2-epoxydodecane (ED) to form secondary amines.
• Incorporation of a chelator within fumed silica (FS) supports to sequester catalytic metallic impurities.
• Integration of polyethylene glycol (PEG) to form hydrogen bonds with PEI, hindering oxygen access.

Main Results:

• The ED-PEI/PEG@FS-TBP adsorbent achieved a high CO2 adsorption capacity of 1.49 mmol g⁻¹ at 298 K and 0.0004 bar.
• Demonstrated remarkable oxidative stability, with a 93% lower deactivation rate constant (kdeact) compared to PEI@FS after 20 days of oxidative aging.
• Exhibited excellent cycling stability and high thermal stability.

Conclusions:

• ED-PEI/PEG@FS-TBP presents a highly stable and efficient material for capturing low-concentration CO2.
• The strategic modifications effectively mitigate urea formation and prevent metal-catalyzed oxidation.
• This adsorbent shows significant potential for practical applications in CO2 capture technologies.