Comparative Carbonization Study of Pyrolyzed Biomass: New Insights Into the Structure and Composition Evolution of Biochar

Abstract

This study investigates the structural and functional transformation of biochar derived from eucalyptus wood powder, rice bran, and bagasse under pyrolysis temperatures of 500 °C, 700 °C, and 900 °C. Using BET, XRD, Raman, FTIR, and particle size analysis, we quantified changes in porosity, crystallinity, and surface chemistry. BET analysis revealed that the highest specific surface area was observed at 500 °C, with eucalyptus biochar achieving 243.2 m²/g. However, at 900 °C, mesopore and macropore formation dominated, with a notable decrease in surface area. XRD and Raman data showed increased graphitization at higher temperatures, with eucalyptus biochar exhibiting the greatest graphitic structure at 900 °C. FTIR results indicated a significant reduction in functional groups at elevated temperatures, enhancing the biochar’s aromatic stability. Resistivity measurements showed a decrease in resistivity, with the resistivity of eucalyptus biochar after 900 °C pyrolysis and ball milling being as low as 0.0196 Ω/cm under 27.3 MPa pressure test, indicating its strong potential in conductive applications. These findings provide quantitative insights into optimizing biochar properties for environmental and energy applications.