Recent advances in organic waste pyrolysis and gasification in a CO 2 environment to value-added products.

The persistent combustion of fossil fuels has resulted in a widespread greenhouse effect attributable to the continual elevation of carbon dioxide (CO ₂ ) levels in the atmosphere. Recent research indicates that utilizing CO ₂ as a pyrolysis gasification medium diminishes CO ₂ emissions and concurrently augments the value of the resultant pyrolysis gasification products. This paper reviews recent advancements in the pyrolysis gasification of organic solid wastes under a CO ₂ atmosphere. Meanwhile, the mechanisms of CO ₂ influence in the pyrolysis and gasification processes were also discussed. In comparison to noble gases, CO ₂ exhibits reactivity with char at≥710 °C, resulting in additional mass loss of the sample. In addition, CO ₂ was able to increase the specific surface area and stability of biochar and reduce biooil toxicity by lowering the content of cyclic compounds in the biooil, while CO ₂ was able to react with GPRs with some volatile products (e.g., light hydrocarbons) to increase biogas yield. Finally, CO ₂ also prevents catalyst deactivation by reducing secondary coke formation. We also recommend directing future attention toward utilizing unpurified CO ₂ in pyrolysis and gasification. This review aims to expand the utilization of CO ₂ and advocate for applying pyrolysis gasification products.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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