Biochar for Wastewater Treatment: Preparation, Modification, Characterization, and Its Applications

Water contamination has become a critical issue, resulting in a decline in global water quality that harms both human health and the environment. Biochar, a porous carbon-rich material produced through the thermochemical decomposition of biomass, has attracted significant attention in wastewater treatment. This review provides a comprehensive overview of biochar preparation methods, modification strategies, characterization techniques, and environmental applications in wastewater treatment. Relevant information was gathered from peer-reviewed articles published in reputable databases. Among various production methods, pyrolysis is the most commonly employed technique for biochar production. The type of biomass and operational conditions, such as residence time, heating rate, and temperature, significantly impact the yield, structure, and composition of biochar. Advanced techniques, including FTIR, XRD, XPS, SEM, TGA, and BET, play a crucial role in characterizing biochar and evaluating its potential environmental applications. This review emphasizes the effectiveness of biochar in removing organic and inorganic contaminants from wastewater and highlights its growing role in environmental remediation. However, there is an ongoing debate regarding its long-term stability and potential release of adsorbed pollutants, which may pose risk if not properly managed. Therefore, this review suggests that future research should also consider its environmental safety, lifecycle sustainability, and regeneration potential. Moreover, establishing quality standards and a regulatory framework for safe and effective biochar use is important to ensure its role as a long-term solution for sustainable water management.