Effect of Pyrolysis Temperature on Physicochemical Properties of Millet Straw Derived Biochar

Agricultural waste is an essential renewable resource that fosters environmental sustainability, global economic development, and energy security. This study aims to examine how the pyrolysis temperature affects the physicochemical characteristics of biochar made from millet straws that have been pyrolyzed at four distinct temperatures: 300, 400, 500, and 600 ◦C. Proximate and ultimate analysis, Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) were used to characterize the generated biochars. The physicochemical properties of the generated biochar were shown to be significantly influenced by the pyrolysis temperature. Ash content, pH, electrical conductivity, fixed carbon, BET surface area, and total C content all rose with increasing pyrolysis temperature, according to the experimental data, but biochar yield, total, cation exchange capacity, and content of O, H, and S all sharply declined. Likewise, when the temperature of pyrolysis increased, the ratios of O/C and H/C tended to decrease. The FTIR measurements showed that biochar produced at a high temperature had a decrease in polarity and an increase in aromaticity. In the meantime, the XRD and SEM examinations demonstrated that the crystalline mineral components and cellulose component of biomass loss increased as the pyrolysis temperature rose.