Recent advances in water remediation from toxic heavy metals using biochar as a green and efficient adsorbent: A review

Heavy metal pollution is a serious environmental problem that poses a threat to human health and the environment. Water pollution by toxic heavy metals is a major cause of this problem, and it can destroy ecosystems, spread disease, and make drinking water unsafe. Biochar is a promising green adsorbent for removing heavy metals from water. It is derived from various biomasses, including agricultural and organic wastes, and has high carbon content, surface area, and stability. These properties enable biochar to effectively remove heavy metals through cation exchange and adsorption. This review summarizes recent advances in biochar modification for enhanced adsorption of heavy metals. It discusses the advantages, applications, challenges, and prospects of this method. Biochar-based advanced oxidation processes (AOPs) have shown promise in the decomposition of heavy metal complexes and the enhancement of the adsorption capacity of free heavy metal ions from industrial wastewater. The review also highlights research gaps and limitations of biochar for water remediation from heavy metals and proposes future research directions. Future research should focus on developing environmentally friendly and cost-effective technologies for scaling up biochar-based heavy metal removal applications. Scheme 1 illustrates the overall summarized presentation of this review article as a graphical abstract.