Review of the Pyrolysis Process and Factors Influencing Biochar Production and Properties, with Emphasis on Agricultural Applications

The unprecedented growth of the global population, accompanied by increasing solid waste generation, has heightened the need for sustainable approaches to the management and valorization of these materials. Among available approaches, thermochemical processes such as pyrolysis have attracted considerable attention as effective methods for converting waste biomass into value-added products, including biochar, bio-oil, and syngas. Pyrolysis is a thermochemical process conducted under oxygen-limited conditions, typically at ۳۰۰-۷۰۰ °C, during which the major biomass components, including cellulose, hemicellulose, and lignin, undergo thermal decomposition, carbonization, and aromatization. As the solid product of pyrolysis, biochar has been widely applied to improve soil quality, enhance nutrient retention, remediate degraded soils, and promote carbon sequestration owing to its stable carbon structure, porosity, cation exchange capacity, and abundance of active functional groups. However, biochar properties and performance depend on multiple factors, including biomass type, pyrolysis conditions, and production methods. This study reviews the pyrolysis process, factors influencing biochar production and properties, and its role in agricultural applications. The literature indicates that slow pyrolysis is more favorable for agricultural applications because of its higher biochar yield and production of a relatively stable carbonaceous product. Increasing pyrolysis temperature generally decreases biochar yield while increasing specific surface area, aromaticity, and carbon stability, whereas feedstock characteristics and other process parameters strongly influence the final product quality. Despite its benefits, challenges such as variability in biochar properties, lack of well-defined standards, modification costs, and limited long-term field studies have constrained the widespread application of this technology. Future optimization of pyrolysis conditions, development of engineered biochars, adoption of emerging technologies, and comprehensive economic and environmental assessments could facilitate the broader application of biochar in sustainable agriculture and waste management.

کلیدواژه ها:

Pyrolysis ، Biochar ، Waste Biomass ، Biochar Properties ، Sustainable Agriculture