Research Progress on Biochar Adsorption of Sewage Pollutants
This article aims to systematically review the research advancements of biochar in the field of wastewater pollutant adsorption and explore its application potential and challenges as an environmentally friendly adsorbent material. With the acceleration of industrialization and urbanization, the massive discharge of various organic and inorganic pollutants into water bodies poses severe threats to both ecosystems and human health, making the development of efficient, cost-effective, and sustainable water treatment technologies a critical focus in environmental engineering. Biochar, a porous carbon material produced through pyrolysis of biomass under oxygen-deficient conditions, demonstrates significant advantages in adsorbing and removing pollutants such as heavy metal ions, organic dyes, drug residues, and nutrients due to its extensive pore structure, large specific surface area, and surface-modifiable functional groups. Starting from theoretical foundations, this paper elucidates how raw materials and pyrolysis conditions critically influence biochar's physicochemical properties, as well as the key mechanisms involved in adsorption—including pore filling, electrostatic attraction, surface complexation, ion exchange, and π-π interactions. Subsequently, it reviews current domestic and international research on biochar's performance in adsorbing various pollutants, analyzes the relationships between raw material selection, modification methods (e.g., acid/alkali treatment, metal loading, composite construction), and adsorption efficiency, and evaluates the effects of adsorption parameters such as pH, temperature, initial pollutant concentration, and contact duration. Although studies confirm biochar's ability to significantly reduce pollutant concentrations, its practical applications face challenges including limited adsorption capacity, insufficient selectivity, unstable regeneration performance, and potential ecological risks. This paper provides a comprehensive review of existing research and emphasizes that future studies should focus on optimizing biochar performance through green modification strategies, investigating its synergistic adsorption mechanisms in complex wastewater systems, evaluating its long-term environmental safety, and facilitating its transition from laboratory research to large-scale water treatment applications, thereby providing more practical technical references for wastewater treatment.