Biochar as a Sustainable Adsorbent for Heavy Metal Removal From Polluted Waters: A Comprehensive Outlook

Biochar is a promising solution in the competent removal of such toxicants due to its cost-effectiveness, natural properties, biologically rich composition, and environment-friendly characteristics. All the possible heavy metals found in industrial effluents and how to treat them with biochar-based adsorption strategies to lead to a cleaner hydrosphere system were analyzed. Biochar interactions in heavy metal adsorption are studied and profiled to a small extent to allow regional knowledge of how these interactions occur and how biochar studies are taking place. Industrial effluents possess various toxic pollutants that extend their exposure to all kinds of living organisms, contaminating and degrading the biosphere. Adsorption helps mitigate difficulties such as wastewater treatment, remediation studies, and hazardous waste management, providing a sustainable and quality life. The characteristics of biochar produced through pyrolysis using different biomasses analyzed are carbon 35–90 wt%, surface area 5–2100 m2/g, and total pore volume 0.001–50 cm3/g at the temperature range of 400°C–750ºC. The optimum conditions required for maximum adsorption efficiency (96%–99%) of heavy metals majorly lie under the range of temperature 30°C–60°C, pH 5–8, and time 30 min to 1 h. The outcome of this review has significant results on remediation techniques, highlighting biochar’s potential as a flexible tool and as an adsorbent in addressing the challenges related to the possible threats implied by heavy metal contamination in industrial effluents.