Supercritical ethanol liquefaction of bamboo leaves using functionalized reduced graphene oxides for high quality bio-oil production

The study investigated the supercritical ethanol liquefaction of bamboo leaves using a functionalized reduced graphene oxide catalyst (GOr). The ZrO2-SrO/GO(r) catalyst consisted mostly of mesopores (95%) with only 5% micropores, which enhances the reactant's accessibility to active sites. The supercritical ethanol liquefaction was carried out in a 150 mL reactor and optimised for bio-oil production using an experimental central composite design (CCD). At optimum operating conditions (375 degrees C, a catalyst-to-biomass ratio of 1:2.5 (wt:wt) and a biomass-to-ethanol ratio of 1:10 (wt/vol), the bio-oil yield derived from bamboo leaves was 47%, which was higher than hydrothermal process (27%). A model was developed from analysis of variance (ANOVA) and validated using experimental data. The predicted and experimental data agreed well with an R-2 of 0.99. The bio-oil had a higher heating value of 35.3 MJ/kg, consisting mainly of esters, phenolic and hydrocarbon compounds.