Insight into biochar as sustainable biomass: Production methods, characteristics, and environmental remediation

Industrialization has contributed significantly to the advancement and sustenance of human civilization. However, it has also posed serious challenges to environmental sustainability, notably through heavy metal pollution, which has severely impacted ecological systems. Recent studies have explored the use of biochar for the removal of heavy metals from aqueous solutions. This review underscores the diverse physicochemical and structural characteristics of biochar, derived from various biomass sources through different pyrolysis processes, and their varying adsorption efficiencies. The review aims to investigate current biochar production technologies, their unique properties, and their maximum removal efficiency and adsorption capacity for heavy metals. The primary adsorption mechanisms, adsorption isotherms, and kinetic models have been identified. Furthermore, the study confirms that optimal conditions—such as the choice of precursors, pyrolysis temperature, and an understanding of the advantages and limitations—are crucial for designing biochar with superior structural and physicochemical properties. This review provides an updated overview of biochar-based heavy metal treatment in aquatic systems, highlighting existing research gaps and suggesting future research directions.