Effects of biomass components and pyrolysis temperature on the adsorption properties of biochar for heavy metals：A review

Industrial activities have led to the increasing pollution of heavy metals in water bodies, which threatens human health. As an economical and effective heavy metal adsorbent, the performance of biochar is significantly affected by the composition of raw materials and pyrolysis conditions. This paper systematically analyzes the pyrolysis characteristics of biomass components (e.g., cellulose, hemicellulose, and lignin) in agricultural and forestry wastes (straw, woody and manure), along with their mechanistic effects on the physicochemical properties of biochar. The removal mechanisms of heavy metals by biochar produced under varying pyrolysis parameters are also discussed. The analysis showed that lignocellulose composition and pyrolysis temperature synergistically controlled the adsorption mechanism. These findings provide insights into tailoring biochar production to target specific heavy metal contaminants. • The contents and pyrolysis process of biomass components are revealed. • Selecte the suitable biomass and pyrolysis temperature for target heavy metals. • Raw material composition and pyrolysis temperature affect the properties of biochar. • The specific surface area and pore volume increase with increasing cellulose content. • Compared with wood-based biochar, crop waste biochar has a higher CEC and pH value.