Microwave-enhanced pyrolysis of algae under CO₂

Algae were microwave-enhanced pyrolyzed under a CO 2 atmosphere at three standard temperatures: 400, 550, and 700 °C. The distribution and makeup of gas and bio-oil in N 2 and CO 2 atmospheres were also compared. To maximize product dispersion increase syngas output during algal pyrolysis and support sustainable biomass consumption, this work explores CO 2 as a reactive carrier gas. While gas output was greater under N 2 (90.8 wt.% vs. 86.5 wt.%), bio-oil yield rose somewhat under CO 2 (from 18.3% to 20.6%). Interestingly, under CO 2 , the syngas content of Dunaliella rose by 23.4-30.4% whereas that of spirulina fell by 60.8-69.7%. Crucially, bio-oil from three microalgae and two macroalgae samples under CO 2 showed almost no PAHs, suggesting safer products.