Heavy Metal Remediation by Natural Adsorbents

Global industrialization and urbanization have led to serious, alarming levels of environmental pollution. Due to the property of high solubility in the aqueous solutions, heavy metals can quickly be absorbed by all living organisms. Once they enter the food chain, it is challenging to detoxify them. Metals are a part of the biological systems, but up to a certain permissible limit, beyond that limit, it becomes hazardous. The physical and chemical technologies require special equipment, it is also labor intensive as well as very costly. Whereas biological technologies of remediation are gaining popularity in order to solve the increasing levels of contamination in the environment. During the recent studies, it is clear that lime precipitation proves to be as one of the effective technique in order to treat inorganic effluent having a concentration of metal higher than 1000 mg/L; usage of new adsorbents, as well as the technique of membrane filtration, are frequently studied and is used for the remediation of the heavy metal-contaminated wastewater. Various techniques have been used for the remediation of contaminated wastewater, it is important to select the most effective method for remediation of metal-contaminated wastewater based on criteria of pH, initial metal concentration, the overall result after the treatment when compared with other technologies along with environmental impact and economics parameter including the capital investment and costs of operation. Finally, the technical applicability along with the simplicity of the plant and cost-effectiveness are major key factors that play an important role in the selection of the suitable treatment system for contaminated wastewater.