A review on application of biochar (biological coal) bioabsorbent in environmental sustainability with the approach of energy, water, and agriculture

Providing sustainable sources of energy, global warming, and maintaining soil health are the main challenges of the 21st century. Biochar has great potential in addressing these global issues and can be effective in achieving sustainable development goals. Biochar obtained from waste biomass (plant residues, urban and rural wastes) is a catalyst for the anaerobic digestion process and increases bioenergy production due to its mineral content and buffering capacity. This article is the result of reviewing valid online papers from Google Scholar, Science Direct, Research Gate, Elsevier, and Springer. The Results showed high advantages of biochar for using in the production of renewable energy and reducing greenhouse gases. Biochar potentially increases methane and hydrogen productions in anaerobic digestion and is efficient in on-site biogas enrichment, leading to biomethane production with a purity of more than 90%. On the other hand, it can be a cheap and potential replacement for the electrode of microbial fuel cells and reduce the cost of ion-based batteries. The application of biochar in the agricultural ecosystem increases carbon sequestration in soil and reduces methane and nitrogen oxide emission. The structural characteristics such as high surface area, optimal pore distribution, surface reactivity, hydrophobicity, and many functional groups make this adsorbent a suitable choice for the remediation of heavy metals from aqueous solutions. The potential of sustainable use of biochar in biological energy production (biogas and biohydrogen), reduction of greenhouse gases, carbon sequestration and soil health, and wastewater treatment along with its future challenges and perspectives is necessary with the Nexus approach of energy, water, and agriculture.