Remediation of Heavy Metals Using Biochar and its Modified Forms

Abstract

Heavy metal contamination has affected various life forms on earth due to their toxic, carcinogenic and bio-assimilative nature. Heavy metals are rapidly transported by various water bodies in our environment. Thus, the remediation of heavy metals in water bodies is essential for sustaining our ecosystems. The treatment technologies available for treating the heavy metals undergoing dynamic biochemical transformations in the environment are a challenge as well as an opportunity for developing alternate cost-effective technologies. Adsorption has emerged as an environment-friendly and cost-effective technology. Biochar, a sustainable and low-cost adsorbent, has shown encouraging results for the remediation of these environmental contaminants. It stands out as a promising adsorbent due to chelating functional moieties apart from high surface area and porosity. These physicochemical attributes of biochar can be modulated using various physicochemical treatments to achieve higher heavy metal removal efficiencies. Biochar is a carbon-neutral material, which can be regenerated and disposed-off easily in an adsorption-based remediation process. This chapter brings out the modifications characteristic of biochar, a comparative statement of properties vis-a-vis biochar and their use in the adsorption of heavy metals, and various mechanisms accounting for their removal.