Comparative thermal and structural analysis of biochar from rapeseed meal and Fraxinus excelsior sawdust
Mohammad Meysami, Amin Rabie, Reza Amini Najafabadi, Amirhossein Meysami, Taghi Isfahani
Abstract
This study investigates the production and thermal characterization of biochar derived from two biomass sources: rapeseed meal and sawdust of Fraxinus excelsior. Biochars were produced through slow pyrolysis at 350°C, and their chemical composition, thermal stability, and carbon structure were analyzed using FTIR, Raman spectroscopy, CHNS analysis, TGA/DTG, and DSC. The results showed high fixed carbon contents of 59.3% for rapeseed meal and 57.6% for wood-based biochars, with sulfur contents below 0.1%. FTIR and Raman analyses confirmed the formation of stable carbonaceous structures with characteristic functional groups. TGA revealed strong thermal stability, with residual masses of 42% and 47% at 1000°C for rapeseed and wood biochars, respectively. DSC analysis demonstrated that wood-derived biochar retained more energy, while rapeseed biochar exhibited higher carbon content. A statistical comparison using bootstrap, effect size, and Bayesian estimation confirmed these trends. Overall, both biochars demonstrate strong potential as sustainable, carbon-rich alternatives for high-temperature industrial applications.