Biochar: A Pyrolyzed Green Fuel from Paddy Straw

Rice straw is a major by-product that possess significant environmental challenges due to its increasing production and the prevalent practice of open burning for disposal. This practice not only leads to air pollution but also hinders soil fertilization and crop establishment. To address these issues, the conversion of rice straw into biochar has emerged as a potential solution. Biochar is produced from rice straw through a thermochemical conversion known as pyrolysis. Due to the environmental benefits and energy efficiency of biochar, it has acquired great recognization. However, concerns regarding the greenhouse gas (GHG) mitigation potential of biochar production need to be addressed. This chapter provides insights into the synthesis of biochar using agricultural waste. RSB (rice straw biochar) is considered a suitable amendment for the ecological and sustainable development of ecosystems. It offers several advantages, including carbon neutrality, slow-release effects of nutrients, and improved soil water content and porosity. Additionally, RSB has been found effective in wastewater and soil contamination treatment. It acts as a sorbent for inorganic and organic sorbents due to its cation exchange ability and wide surface area. The physical properties of rice straw, such as bulk density and moisture content, plays an important function in its handling as well as storage. Processing methods such as pelletization and briquetting can increase its density and reduce its volume for easier storage and transportation. The thermal properties of rice straw, including calorific value and volatile matter, influence its conversion into biofuels. Chemically, cellulose, hemicellulose, and lignin are major components of lignocellulose found abundantly in biochar. These polymers vary quantitatively and qualitatively based on factors such as variety, season, and geographical location. Understanding the rice straw’s chemical composition is essential for the utilization of it as a feedstock and soil fertility enhancer. The biochar production from rice straw is carried out through thermochemical conversion technologies, including pyrolysis. However, the GHG mitigation potential of biochar production needs further investigation to optimize the process and enhance its environmental benefits. In nutshell, the utilization of rice straw as biochar offers a sustainable and efficient way to manage agricultural waste, improve soil fertility, and mitigate environmental issues. Further research and development are required to optimize the production process and explore the full potential of rice straw biochar in various applications.