Carbon capture from petrol-engine flue gas: Reviving algae-based sequestration with integrated microbial fuel cells

Strengthening the existing CO2 capture technologies is crucial for averting the imminent climate crisis. The present study undertakes the algae-assisted microbial fuel cell (MFC) for indirect CO2 capture via bicarbonate utilization through natural photosynthesis process. The flue gas is first cooled using a heat exchanger and then directed to a sieve-plate absorption column where sodium carbonate supplemented wastewater absorbs CO2 generating flue gas-derived bicarbonates (FGDBs). The FGDBs are added in the plastic bag photobioreactors (PBRs) coupled with the MFC for absorption by Chlorella vulgaris. Adding FGDB at the MFC cathode increased the algae biomass productivity two times (0.677 +/- 0.086 Kg/m3/d) compared to the cathode without FGDB. The algae could efficiently utilize 76.84 +/- 1.23 %. More than 50 % of sodium carbonate can be recycled for the next round of CO2 capture. FGDB supplementation at the cathode improved MFC's electrical energy production (0.0066 kWh/m3) by 1.5 times through enhanced anodic and cathodic currents. Therefore, the present study offers a biochemical CO2 sequestration process that generates power, algae biomass, and treats water by utilizing algae-assisted MFC for flue gas carbon capture.