Value-added biocarbon production through slow pyrolysis of mixed bio-oil wastes: studies on their physicochemical characteristics and structure–property–processing co-relation

In this work, mixed bio-oil (MBO) is transformed into valuable biocarbon through slow pyrolysis technique. MBO was accomplished in a semi-batch reactor at 600 and 900 °C temperature, 10 °C min⁻¹ heating rate, and 30 min holding time under a non-oxidizing environment. The produced mixed bio-oil-derived biocarbon (MBOB) was characterized by its surface properties, thermal stability, elemental composition, thermal conductivity, BET surface area, surface morphology, and electrical conductivity. The pyrolysis outcomes established that the temperature has a predominant impact on the variation in yield and properties of MBOB. Characterization results of MBOB exposed increased properties (thermal stability, electrical and thermal conductivity, graphitic content, carbon content, and HHV) at 900 compared to 600 °C. Also, the elemental and EDS investigation of MBOB established a broad diminution in O₂ and H₂ at 900 than 600 °C. The purest form of carbon with enhanced thermal stability, higher carbon content, smoothness, and bigger particles of biocarbon (verified by SEM) is accomplished at 900 °C. The electrical and thermal conductivity (EC and TC) of MBOB increased with increasing the temperature from 600 to 900 °C due to the close contact of biocarbon particles. Finally, an investigation of the particle size of MBOB established that the majority of particles are within 1.5 to 1.7 µm. Graphical abstract: [Figure not available: see fulltext.].