Mechanochemically Activated, Calcium Oxide-Based, Magnesium Oxide-Stabilized Carbon Dioxide Sorbents

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Current carbon dioxide capture and storage (CCS) technologies, like amine scrubbing, are prohibitively expensive.
• Calcium looping offers a potentially more affordable alternative for CO2 capture via CaO carbonation.
• Natural CaO sorbents like limestone suffer from deactivation due to thermal sintering.

Purpose of the Study:

• To develop a scalable and cost-effective method for producing stabilized CaO-based CO2 sorbents.
• To investigate the stabilization mechanism of CaO using MgO.
• To improve the CO2 uptake capacity of CaO sorbents.

Main Methods:

• A scalable wet mechanochemical activation route was employed to synthesize MgO-stabilized CaO sorbents.
• Synthesis conditions were optimized based on a detailed understanding of the MgO stabilization mechanism.
• Characterization of sorbent performance for CO2 capture.

Main Results:

• A novel MgO-stabilized CaO sorbent was successfully prepared using wet mechanochemical activation.
• The quantity of MgO required for stabilization was reduced to as low as 15 wt%.
• The developed sorbents demonstrated a CO2 uptake capacity 200% higher than that of reference limestone.

Conclusions:

• Wet mechanochemical activation provides a scalable route for producing highly efficient CaO-based CO2 sorbents.
• MgO stabilization effectively mitigates the deactivation of CaO sorbents, enhancing their long-term performance.
• This advancement offers a more economically viable approach to CO2 capture for climate change mitigation.