In-situ catalytic bio-oil production from hydrothermal liquefaction of Cu-impregnated water hyacinth: Screening of reaction parameters

Abstract

The rapid growth of water hyacinth (WH) is a major concern worldwide as it adversely affects the aquatic world's life by lowering the oxygen level or depleting the water's nutrients. In this study, the hydrothermal liquefaction of WH was performed by impregnating it with Cu and Co to enhance bio-oil production. It has been found that the Cu-impregnated-WH exhibited a high bio-oil yield in comparison to Co-impregnated-WH. The influence of reaction parameters e.g., reaction residence time, temperature, and the biomass-to-water ratio were also screened to achieve the maximum liquefaction. Further, the water-to-biomass ratio significantly tailored the bio-oil yields. It has been found that 0.2M-Cu-impregnated-WH with a 1:9 biomass-to-water ratio and 270 °C/30 min were the best-optimized conditions for the highest total bio-oil yield (41 wt%) and conversion (83%). The isolated optimum bio-oils were characterized by the GC-MS analysis to ascertain the composition of compounds that attributed to the maximum area% of N-containing and phenolics compounds. The maximum amount of both types of bio-oils was found to be high from the liquefaction of Cu-impregnated WH compared to non-catalytic. Moreover, the char was characterized by XRD, FT-IR, and TEM analysis, which confirmed the breaking of linkages of WH, and the presence of Cu in the form of CuO. The findings of the study clearly signify the potential of WH for sustainable energy production and the char obtained can be used for various other applications.