Pyrolysis-catalysis of medical waste over metal-doping porous biochar to co-harvest jet fuel range hydrocarbons and H2-rich fuel gas

Abstract

This study developed a dual-stage pyrolysis-catalysis pathway to valorize disposal syringe waste into liquid hydrocarbons and H2-rich fuel gas. Two typical biomass sources (corn stover and cotton stalk) were used to synthesize metal-doping porous biochar catalysts through in situ carbothermal reduction treatment. For corn stover-derived biochar catalysts, Fe/C1 (Fe-doping corn stover biochar catalyst) presented a high yield (61.06 wt%) of liquid hydrocarbons with over 78% of jet fuel range (C8 – C16) hydrocarbons, and the 2,4-dimethyl-1-heptene (C9H18) yield reached 101.6 mg/gsyringe. Bimetallic Zn-Fe/C1 (Zn-Fe co-doped corn stover biochar catalyst) was in favor of H2 production, with a proportion of over 37 vol%. Among the cotton stalk-derived biochar catalysts, bimetallic Zn-Fe/C2 (Zn-Fe co-doped cotton stalk biochar catalyst) achieved a highest yield (62.76 wt%) of liquid hydrocarbons, indicating a positive synergistic effect of bimetallic Zn-Fe composite on liquid hydrocarbons production. However, Fe/C2 (Fe-doping cotton stalk biochar catalyst) was responsible for a high yield (over 93 mg/gsyringe) of 2,4-dimethyl-1-heptene and a high selectivity (over 76%) of jet fuel range hydrocarbons. Additionally, a logical reaction mechanism was provided for dual-stage pyrolysis-catalysis of syringe waste over metal-doping porous biochar catalysts. Briefly, this work provides a green route by using metal-doping biochar for valorization of medical wastes into liquid hydrocarbons and H2-rich fuel gas.