<p>Worldwide, one of the leading environmental concerns is heavy metal contamination in water, which endangers both the ecosystem and human health. The techniques for the remediation of heavy metal contamination are ion exchange, solidification, precipitation, adsorption, and electrochemical reduction. Biochar is an environmentally friendly and cost-effective sorbent that effectively adsorbs heavy metals from water. It is derived from various biomass sources, including sewage sludge, agricultural residues, industrial waste, forest products, and aquatic waste. Despite having properties like functional groups, and potential for heavy metal removal, biochar has limited specific surface area, functional groups, and porosity. Modifying the biochar surface can improve its physicochemical qualities by altering its functional groups, active sites, porosity and enhancing heavy metal adsorption ability. The average removal efficiency of modified biochar ranging from 75 to 95%, depending on modification type, biochar feedstock and experimental conditions. With these qualities, modified biochar can effectively remediate heavy metals via ion exchange, surface precipitation, electrostatic attraction, co-precipitation, complexation, physical adsorption, and π interaction. The review paper presents a comprehensive overview of the diverse feedstocks utilized for biochar synthesis, various methods of biochar production, and the recent physical, chemical, and biological activation techniques. A bibliometric analysis is provided to understand recent trends in using biochar for the remediation of heavy metals at the global level. This article briefly discusses the sorption mechanism involved in heavy metal contaminant removal. Furthermore, regeneration strategies and the reusability of modified biochar are summarized to promote sustainable development. Future research directions are proposed for more efficient use of biochar in practical wastewater treatment.</p> Graphical Abstract <p></p>