Black gold - biochar: transforming agro-based biomasses into sustainable environmental solutions

The escalating waste generated from agriculture, forestry, aquatic, and industrial sectors poses significant challenges, including environmental pollution, increased greenhouse gas emissions, and depletion of valuable resources. In response to these pressing issues, biochar has emerged as a renewable and sustainable biotechnological approach. Biochar, known as the Black Gold, is derived from the pyrolysis of various organic waste materials, reducing waste and creating a useful product for protecting the environment. Agriculture, forestry waste, food and fiber processing residues, and grassland biomass are the main sources for biochar production. Lignocellulosic materials with low moisture content are the preferred feedstock for biochar production. Biochar has diverse applications in carbon sequestration, soil remediation, and water and air purification, including toxic heavy metals (HMs) removal (e.g., chromium, arsenic, and lead). Biochar applications vary depending on the composition of the feedstocks used in the pyrolysis process. Chemically modified pristine biochar exhibits enhanced adsorption capacities for HMs, making it particularly effective for soil and water decontamination applications. This review highlights the important roles of biochar material for sustainable environmental applications, particularly in HMs removal from contaminated water systems. Innovations in biochar technologies are beneficial bioengineering activities to address the intertwined challenges of waste management toward environmental sustainability.