Investigating innovative techniques for biochar modification to enhance the removal of heavy metals from aqueous environments: a comprehensive review

The prevalence of heavy metals in aquatic ecosystems threatens health and the environment, highlighting the need for sustainable removal methods. Biochar is emerging as a promising eco-friendly adsorbent due to its unique physicochemical properties. This study extensively evaluates innovative strategies and novel approaches to enhance biochar's effectiveness in heavy metal removal. The fundamental theories underlying heavy metal adsorption onto biochar and the critical variables influencing this process are thoroughly analysed. Various modification methods, encompassing physical, chemical, and biological approaches, are explored to enhance the selectivity and adsorption capacity of biochar. The significance of employing diverse feedstock materials in biochar production and their impact on adsorption efficiency is emphasized. The study investigates the synergistic effects of incorporating metal oxides and other nanomaterials into the biochar matrix for improved heavy metal removal. Additionally, the application of surface functionalization, introducing functional groups to enhance interactions between heavy metals and biochar, is critically examined. This research addresses comprehensive biochar modifications to achieve the dual objectives of environmental sustainability and economic viability in heavy metal remediation. A meticulous evaluation is conducted on potential drawbacks and challenges associated with biochar-based remediation procedures. The study provides valuable insights into the promising future of biochar as a cost-effective and environmentally friendly solution for removing heavy metals from aquatic environments. This study addresses comprehensive biochar modifications, encompassing the latest five-year updates and well-documented case studies, providing a holistic understanding of heavy metal remediation and emphasizing environmental sustainability and economic viability. The subject mainly aligns with Sustainable Development Goals (SDGs): Clean Water and Sanitation (SDG 6). The objective is to guide environmental remediation experts, legislators, and academics towards more sustainable and effective approaches to addressing heavy metal pollution.