Effect of pyrolysis temperature on the physiochemical properties of wheat straw biochar

The wheat straw (BCW) generated by slow pyrolysis at 300, 400, 500, and 600 °C for one hour residence time at a heating rate of 10 °C/min was characterised to assess the impact of pyrolysis temperature on the biochar yield and its physicochemical properties. Proximate and elemental analyses, Brunauer-Emmett-Teller (BET) surface area analysis, Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) analyses were employed to characterize the biochar samples. Increased in pyrolysis temeperature had significant negative correlation with biochar yield, volatile matter (VM), moisture content (MC), cation exchange capacity (CEC), O, H, and N atoms, as well as the ratios of O/C, H/C, and N/C, but showed positirive correlations with content of fixed carbon (C), the C content, ash, pH, and electrical conductivity (EC). Moreover, the FTIR result showed that as the temperature of pyrolysis increased, O-containing functional groups declined. The BET surface area increases at higher pyrolysis temperatures mostly as a result of increased micropore volume and surface area. Conclusively, the result demonstrated that, pyrolysis temperature has a significant impact on the characteristics of biochar, hence, different pyrolysis temperatures result in biochar with distinctive qualities that can be used for various purposes.