Biochar: Porous Carbon Material, Its Role to Maintain Sustainable Environment

Of late, the conversion of agricultural residues into biochar has been considered a sustainable solution to burning of biomass worldwide. Biochar, a carbon-rich soil additive, has been recommended as a useful residue management approach for carbon accretion, modification of soil fertility, and pollutant immobilization. It contributes significantly to enhance soil physicochemical and biological qualities, as well as to check climate change by decreasing harmful gas emissions from the environment. Biochar is made by thermally decomposing different biomasses, like straw, manure, wood, or leaves at temperatures ranging from 300 to 700 ℃ with a limited supply of oxygen. Biochar application into the soil can enrich the soil with nutrients by promoting better soil aggregation, water retention, microbial growth, and betterment of other soil physical, chemical, and biological properties. Biochar is an alternate option for heavy metal reclamation in polluted soils and water because of its porous structure, alkaline nature, and greater surface area containing numerous functional groups. Biochar treated soils are very effective in adsorption of major organic–inorganic pollutants and environmental contaminants from soil. Biochar is useful as a sorbent to expel different heavy metals and other organic pollutants from waste water because it includes different oxygen-bearing functional groups such as phenolic, hydroxyl, and carboxyl. As a whole, biochar addition helps to maintain the sustainability of the environment. However, a paucity of prolonged, well-planned field reports on the efficiency of biochar on various soil types and agro climatic zones limits our perceptions of ability of biochar to improve nutrient retention, crop productivity, remediate contaminated soil, and mitigate climate change. This chapter has discussed the biochar production processes, its uses in agriculture and the functions in alleviating climate change, and the potential challenges associated with their long-term applications.