Effects of pyrolysis parameters on the yield and properties of biochar from pelletized sunflower husk

Pyrolysis of biomass residues from agriculture and food processing industry allows production of biochars with diverse physical and chemical properties for a wide range of applications in agriculture and environmental protection. Biochars produced from pelletized sunflower husks through slow pyrolysis in the range of temperatures (480–580°C) showed total carbon of 70.53%–81.96%, total nitrogen of 1.2%, alkaline pH (9.37–10.32), low surface area (0.93–2.91 m2 g-1) and porosity of 13.23–15.43%. Higher pyrolysis temperatures resulted in lower biochar yields. With the increase in temperature the content of organic matter, nitrogen, Ca and Mg decreased whereas the increase in temperature resulted in higher contents of total carbon and phosphorus. Produced biochars showed potential for agricultural applications