(2015) Environmental Science and Technology_Synergetic sustainability enhancement via utilization of carbon dioxide as carbon neutral chemical feedstock in the thermo-chemical processing of biomass

Kwon E.E., Cho S.-H., Kim S.

(American Chemical Society) Environmental Science and Technology ISSN: 0013936X Vol.49 Issue.8 Article No. DOI: 10.1021/es505744n

This study investigated the utilization of CO₂ as carbon neutral chemical feedstock in the thermo-chemical processing (i.e., pyrolysis and gasification) of biomass to enhance sustainability via modification of the composition of end products. To justify the universal function of CO₂ in the thermo-chemical process, the biomass experimented on in this work was not limited to ligno-cellulosic biomass; seaweed (i.e., red macroalgae) was used to expand biofuel feedstock beyond terrestrial biomass. Our experimental results validated the achieved enhanced generation of ∼200% for H₂ and ∼1000% for CO by means of adopting CO₂ in the thermo-chemical process, as compared to the case in N₂. This can be explained by the enhanced thermal cracking of volatile organic carbons (VOCs) evolved from the thermal degradation of biomass and the reaction between CO₂ and VOCs. Considering mass balance under our experimental conditions, we confirmed reaction between CO₂ and VOCs, which was universally observed in pyrolysis of all biomass samples used in this work. Thus, the identified influence of CO₂ in the thermo-chemical process can be directly applied in a variety of research and industrial fields, which would be environmentally desirable. © 2015 American Chemical Society.