Biochar from Agricultural Waste: Enhancing Environmental Sustainability and Economic Feasibility

Biochar is a porous, carbonaceous material that can be derived from agricultural wastes such as straw, husk, stover, stalks, hulls, shells, leaves, etc. Biochar has gained prominence as an environmentally sustainable tool. In this chapter, synthesis of biochar, its characterization, applications, environmental sustainability, techno-economic assessment (TEA), etc., are outlined. Synthesis of biochar, particularly using thermochemical methods like pyrolysis, carbonization, torrefaction, gasification, etc., is highlighted, and their studies are compiled. Moreover, focus has been laid on various techniques (activation or modification) for the production of modified or engineered biochar, which has diverse applications due to improved physicochemical properties. Characterization techniques like scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, etc., which are essential for morphology, porosity, and confirmation of functional groups, are also elaborated in this chapter. Biochar, being an environmentally sustainable material, has wide applications in soil remediation, wastewater and air treatment, greenhouse gas (GHG) removal, energy storage, carbon sequestration, etc. Studies related to all these applications have been examined along with life cycle assessment (LCA) and TEA. The usefulness of an integrated biorefinery is also highlighted in this chapter. Overall, this study underscores the importance of biochar in attaining sustainability and achieving circular-economy goals by valorizing waste material for the synthesis of biochar for various applications.