CO₂ to fuel via pyrolysis of banana peel

Considering the global production of banana, a large amount of banana peel (BP) waste is being generated world widely. Thus, pyrolysis of BP was investigated to develop a technically reliable platform for the simultaneous waste management and energy recovery. To synergistically increase the sustainability of BP pyrolysis, this study adopted carbon dioxide (CO₂) as a raw material and examined the production of syngas as a function of temperature in reference to the N₂ environment. CO₂-cofeed pyrolysis expedited the thermal cracking of volatile pyrolysates from BP, resulting in the gas phase homogeneous reaction between CO₂ and the pyrolysates at ≥420 °C. This promoted CO formation in the temperature region, and more than 20 times of CO formation was shown in comparison with pyrolysis in the N₂ environment. These genuine mechanistic roles of CO₂ offer a new mean for converting CO₂ into CO. Also, CO₂-cofeed pyrolysis of BP increased the aromaticity of biocrude (pyrolytic oil), expediting dehydrogenation of liquid pyrolysates without using any catalysts. Moreover, modification of biochar surface morphology under the CO₂ condition was observed. Conclusively, this study informed a key clue for maximizing the carbon exploitation in the carbonaceous waste, which directly leads to the environmental benefits due to the use of CO₂ as a reactant. CO₂-cofeed pyrolysis can be an innovative and strategic thermo-chemical process to valorize food wastes. Copyright © 2019 Elsevier B.V. All rights reserved.