Exploration of structured solid amine adsorbents for CO₂ capture: PEI-loaded composite foam material

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Solid amine adsorbents are crucial for CO2 capture, but their industrial application is limited by challenges in shaping, mechanical strength, and pore structure integrity.
• Existing shaping methods for powdered adsorbents often lack universality, involve complex procedures, and can degrade pore structures, hindering practical use.

Purpose of the Study:

• To develop a scalable, cost-effective strategy for fabricating structured solid amine adsorbents with improved properties for CO2 capture.
• To address limitations of current shaping techniques, focusing on enhanced mechanical strength, pore structure, and CO2 adsorption performance.

Main Methods:

• Fabrication of structured adsorbents using porous materials (biochar), sulfur-aluminum cementitious binders, and hydrogen peroxide (H2O2)-assisted chemical foaming.
• Integration of micro-mesopores from the carrier with macropores generated via foaming and hydration to create a hierarchical pore structure.
• Evaluation of CO2 adsorption capacity, amine utilization, mechanical strength, reusability, and adsorption kinetics.

Main Results:

• The structured adsorbent demonstrated excellent compressive strength (∼77.33 N) and a CO2 adsorption capacity of 60.04 mg/g at 90°C.
• High amine utilization (68.52%) and good reusability with only a 7.59% capacity reduction after five cycles were achieved.
• The method showed strong material adaptability, successfully applied to synthetic resin and nano-fumed silica carriers, with rapid initial CO2 adsorption (76.38% in 2 min).

Conclusions:

• The proposed fabrication strategy offers an effective and scalable pathway for producing structured solid amine adsorbents, overcoming key industrial application barriers.
• This approach enhances mechanical stability and CO2 capture performance, making it suitable for practical CO2 capture technologies.
• The study highlights the importance of amine utilization and introduces a novel evaluation chart for assessing both adsorption capacity and utilization simultaneously.