Sustainable valorization of bamboo sawdust via catalytic pyrolysis into renewable liquid fuel and value-added chemicals

Bamboo biomass is a promising resource for the manufacture of sustainable chemicals and energy due to its quick growth and widespread availability. This study delves into the thermal and catalytic pyrolysis of bamboo sawdust (BBS) using a semi-batch reactor operating at 600 °C, with a heating rate of 30 °C min⁻¹ and a nitrogen flow rate of 100 ml min⁻¹. Various proportions of biomass and catalyst were blended to explore the optimal yield and enhanced characteristics of the pyrolysis oil. Characterisation of BBS and pyrolysis oil involved proximate and elemental analyses, heating value, density, FTIR, XRD, FESEM, BET surface area, GC-MS, viscosity, and moisture content assessments. Results revealed that thermal pyrolysis of BBS yielded 33.35 wt%, while the addition of 5 wt% ZSM-5 catalyst increased the liquid yield to 35.25 wt%. The thermal pyrolysis oil exhibited higher viscosity (63.11 cSt), lower pH (2.02), and increased oxygen content (24.23 wt%), whereas the utilisation of catalysts reduced viscosity (53.95 cSt), increased pH (3.27) and decreased the oxygen content (12.19 wt%). FTIR analysis confirmed the presence of O-H, C-C and C=C functional groups in pyrolysis oils. GC-MS analysis demonstrated that the introduction of catalysts enhanced hydrocarbons, furan-based products, and alcohols while reducing acids, phenols, and nitrogen-containing compounds. Further, characterisation of the biochar revealed 67.63wt%, 31.31 MJ kg⁻¹, 26.86 m² g⁻¹, 9.32, and 18.19% carbon content, HHV, BET surface area, pH, and water holding capacity (WHC). In summary, the study concludes that the pyrolysis of BBS with catalysts improves the properties and yield of the resulting oil, indicating promising opportunities for the utilisation of bamboo biomass in renewable energy and chemical production.