Biomass-based adsorbents for post-combustion CO₂ capture: Preparation, performances, modeling, and assessment

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Adsorbents are crucial for post-combustion CO2 capture.
• Biomass-based adsorbents (BAs) offer a sustainable, cost-effective alternative.
• Understanding BA preparation, performance, and application is vital for effective CO2 capture.

Purpose of the Study:

• To comprehensively analyze the methods, theories, and technologies of biomass-based adsorbents for CO2 capture.
• To investigate the preparation, activation, modification, and influencing factors on BA performance.
• To explore adsorption mechanisms, thermodynamics, kinetics, regeneration, and application pathways.

Main Methods:

• Analysis of BA preparation via pyrolysis, chemical activation, and heteroatom modification.
• Correlation studies on feedstock properties (carbon content, moisture) and preparation conditions (temperature, time) with CO2 adsorption capacity.
• Thermodynamic and kinetic modeling using Freundlich isotherm and pseudo-second-order models; quantum chemistry analysis.

Main Results:

• Optimal BAs prepared by pyrolysis and dual heteroatom modification enhance adsorption sites.
• Adsorption capacity is positively correlated with specific surface area (R=0.880) and microporous volume (R=0.773).
• Adsorption capacity decreases with temperature but increases with pressure and CO2 concentration; regeneration is energy-efficient (<3.44 MJ/kg CO2) with low loss (<8%).

Conclusions:

• Biomass-based adsorbents exhibit high efficiency, low cost, and good sustainability for CO2 capture.
• Optimized preparation and modification strategies significantly improve adsorption performance.
• A clear technical pathway for BA application in CO2 capture is proposed, alongside identified challenges.