Integrated CO₂ capture and conversion via H₂-driven CO₂ biomethanation: Cyclic performance and microbial community...

Area of Science:

• Biotechnology
• Environmental Science
• Microbiology

Background:

• Carbon dioxide (CO2) emissions pose significant environmental challenges.
• Integrated CO2 capture and conversion (iCCC) offers a promising solution for CO2 mitigation.
• Biomethanation presents a sustainable pathway for CO2 utilization.

Purpose of the Study:

• To investigate hydrogen-driven CO2 biomethanation for iCCC.
• To evaluate the cyclic performance and stability of CO2 absorption and carbonate regeneration.
• To identify microbial communities involved in the process.

Main Methods:

• Enrichment of anaerobic microbial communities in H2-supplied, Na2CO3-amended media.
• Performance evaluation of CO2 absorption and regeneration cycles at different pH values (9.0, 9.5, 10.0).
• Analysis of microbial community structure and function.

Main Results:

• Successful CO2 capture and conversion to methane via biomethanation.
• Effective restoration of CO2 absorption capacity and stable carbonate recycling over multiple cycles.
• The pH=10.0 group exhibited the highest CO2 absorption capacity (65.3 mmol/L in the 5th cycle).
• Alkalitolerant microbial communities dominated, facilitating CO2 biomethanation under varying pH conditions.

Conclusions:

• Hydrogen-driven CO2 biomethanation is a viable strategy for iCCC.
• The process demonstrates stable cyclic performance and efficient carbonate recycling.
• Alkali-tolerant microorganisms play a crucial role in the success of this iCCC approach.