Optimizing CaO-based CO₂ adsorption: Impact of operating parameters.

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Industrial CO2 emissions pose significant environmental challenges.
• Calcium oxide (CaO)-based materials offer a potential solution for CO2 capture.
• Effective CO2 capture technologies are crucial for climate change mitigation.

Purpose of the Study:

• To systematically investigate the impact of key parameters on CO2 capture efficiency using CaO.
• To determine optimal conditions for CO2 adsorption using commercial CaO.
• To understand the underlying mechanisms and limitations of CaO-based CO2 capture.

Main Methods:

• Thermogravimetric analysis (TGA) was employed to study CO2 capture efficiency.
• Commercial CaO was characterized using SEM, BET, and FTIR techniques.
• Kinetic modeling (pseudo-second-order) was used to analyze adsorption mechanisms.

Main Results:

• Optimal CO2 capture capacity of 0.62 g/g and a rate of 0.14 g/g/min were achieved at 750°C, 7 mg CaO, 20% CO2, and 20 mL/min flow rate.
• High-temperature adsorption (750°C) preserved CaO's hierarchical pore structure, enhancing surface area and mitigating sintering.
• Kinetic analysis confirmed that chemisorption is the dominant mechanism for CO2 capture.

Conclusions:

• The study identified optimal conditions for efficient CO2 capture using CaO adsorbents.
• Preserving pore structure at elevated temperatures is key to maintaining adsorbent performance.
• Findings provide insights into mass/heat transfer limitations, guiding the development of advanced Carbon Capture, Utilization, and Storage (CCUS) systems.