Study on the prepared bio-oil by catalytic hydrothermal liquefaction of antibiotic residues in ethanol-water reaction system with transition metal modified HZSM-5

• Catalytic hydrothermal liquefaction of antibiotic residue was carried out by modifying HZSM-5 with different transition metals. • Fe/HZSM-5 showed better hydrogenation function, while Cu/HZSM-5 showed better nitrogen removal function. • The catalytic mechanism of modified HZSM-5 is changed in the valence state of the transition metal. In this study, the raw materials of antibiotic residues and the catalysts of transition metals (Fe, Cu and Co) modified HZSM-5 were used to prepare bio-oil in the ethanol–water (50/50, v/v) reaction system. The results showed that the bio-oil produced by catalysis was mainly composed of esters and single metal modified HZSM-5 was more effective than multi-metal modified HZSM-5. Among all the modified HZSM-5 catalysts, Fe/HZSM-5 showed better hydrogenation effect and Cu/HZSM-5 showed better denitrification effect. And the addition of Fe/HZSM-5 could lead to the H content of 9.20 wt% in bio-oil and the high calorific value of 39.35 MJ/kg. In addition, the catalytic mechanism of Fe/HZSM-5, Cu/HZSM-5, and Co/HZSM-5 was inferred in this study. These results may provide a new idea for the study of hydrothermal liquefaction of antibiotic residues.