Department of Pure and Industrial Chemistry, Faculty of Physical Sciences, Bayero UniversityKano, PMB, Kano, Nigeria
Agricultural waste is a vital renewable resource that promotes environmental sustainability, global economic growth, and energy security. The focus of this study is on the effect of pyrolysis temperature on physicochemical properties of biochar derived from millet straws as an agricultural wastes pyrolyzed at four different pyrolysis temperatures of 300, 400, 500 and 600 .C for 30, 60, 90, and 105-minutes residence time, respectively. The produced biochars were characterized by proximate and ultimate analysis, Brunauer.Emmett.Teller (BET), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Pyrolysis temperature was shown to have a strong influence on physicochemical characteristic of biochar samples. The experimental data shows that as pyrolysis temperature increased, ash content, pH, electrical conductivity, cation exchange capacity, fixed carbon, BET surface area, and total C content increased while biochar yield, total content of O, H and S significantly decreased. Similarly, the ratios of O/C, H/C, tended to decrease with the upsurge of pyrolysis temperature. The FTIR data indicated an increase in aromaticity and a decrease in polarity of biochar produced at a high temperature. Meanwhile, the XRD showed that with increased in pyrolysis temperature, cellulose component of biomass loss and crystalline mineral components increased. The result suggest that biochar produced at higher pyrolysis temperatures possess stable carbon, which can be used to sequester carbon when used as soil amendment.
• Millet straws biochar was produced from the batch pyrolysis at different temperatures of 300, 400, 500, and 600.
• The produced biochars were characterized for proximate, and ultimate analysis, as well as the BET, FTIR and XRD analyses for surface area, functional groups, and crystalline nature the biochars, respectively.
• Pyrolysis temperature was found to have significant effect on the physicochemical properties of the biochar.
• Base on the physicochemical properties of millet straws biochar, the millet straws biochar could be a source of soil amendment, in carbon sequestration, as an adsorbent for organic and inorganic contaminants from the environments.
Millet straw, Biochar, Pyrolysis, Physicochemical properties
