Modification of hydrothermal liquefaction products from Arthrospira platensis by using carbon dioxide

This study mainly reports that utilizing CO₂ as a reaction medium in hydrothermal liquefaction of Arthrospira platensis, as a model feedstock of microalgal biomass, provides a means for modifying the chemical constituents in microalgal bio-oil produced via hydrothermal liquefaction. Prior to hydrothermal liquefaction, the total lipid content of A. platensis was measured as ~ 3.5 wt% (dry basis). Thermal degradation of A. platensis and the major pyrolytic gases from the thermal degradation of A. platensis were characterized to gain an insight into the physico-chemical influences of CO₂ in hydrothermal liquefaction. Based on the experiment's findings, hydrothermal liquefaction of A. platensis was conducted to evaluate the influence of CO₂. Hydrothermal liquefaction of A. platensis in CO₂ decreased the composition of N-containing species from 63 to 59% and that of O-containing species from 31 to 27% in the bio-oil, significantly suggesting that using CO₂ improves the quality of bio-oil as a transportation fuel. Copyright © 2017 Elsevier B.V. All rights reserved.