Effect of microwave-assisted wet torrefaction on liquefaction of biomass from palm oil and sugarcane wastes to bio-oil and carbon nanodotsinanoflakes by hydrothermolysis and solvothermolysis

This study aimed to produce bio-oils from various lignocellulosic biomass, namely palm empty fruit bunch (EFB), palm fiber (PF), sugarcane bagasse (SB), and sugarcane leaves (SL). Hydrothermal liquefaction, an environmentally benign process, was applied for converting wet bio-resources to bio-oils. The effect of Na2CO3 and La2O3 catalysts were investigated at 300 degrees C, the results showed higher bio-oil yield from Na2CO3 compared to La2O3. The use of glycerol solvent as a hydrogen donor substantially enhanced bio-oil yield for 300% compared to aqueous solvent. Furthermore, the microwave-assisted wet torrefaction (800 W for 20 min) pretreatment employed for EFB helps to increase aliphatic and aromatic compounds and enhance the light and heavy bio-oils yields to 76.80 wt%. SB and EFB are promising biomass for solvothermolysis liquefaction giving the highest energy ratio. A substantial amount of carbon nanodots and nanoflakes were produced from hydrothermolysis and solvothermolysis liquefaction of EFB with average mean diameters of 49.5 and 100.4 nm, respectively. (C) 2020 Elsevier Ltd. All rights reserved.