Tailoring biochar surface functionalities via pyrolysis temperature for enhanced sustainable soil remediation

Biochar has gained considerable attention as an environmentally friendly and sustainable material for soil remediation due to its unique physicochemical properties and versatile adsorption capabilities. Among the factors influencing biochar performance, pyrolysis temperature is one of the most critical parameters, as it governs the development of surface functional groups, pore structure, aromaticity, surface area, and mineral composition. This study examines the role of pyrolysis temperature in tailoring the surface functionalities of biochar and its subsequent impact on the remediation of contaminated soils. Biochar produced at lower pyrolysis temperatures generally exhibits abundant oxygen-containing functional groups, which enhance nutrient retention and facilitate the complexation of heavy metals. In contrast, higher pyrolysis temperatures promote greater surface area, pore volume, and aromatic carbon structures, thereby improving the adsorption of organic pollutants and increasing long-term stability in soil. The findings demonstrate that optimizing pyrolysis temperature enables the production of biochar with application-specific properties capable of effectively immobilizing contaminants while improving soil fertility, microbial activity, and overall soil health. Furthermore, the use of biomass-derived biochar supports waste valorization, carbon sequestration, and circular economy principles, making it a promising strategy for sustainable environmental management. Despite these advances, gaps remain in understanding the long-term stability and transformation of biochar surface functionalities under real soil-plant conditions, warranting further mechanistic and field-based investigations. Overall, tailoring biochar surface functionalities through controlled pyrolysis temperature offers an effective approach for enhancing soil remediation efficiency, guiding future research toward optimized, contaminant-specific biochar design for sustainable agricultural and environmental practices.