ABSTRACT

Pollution by heavy metals is one of the major environmental concerns of modern society because of their persistent and bioaccumulative nature unlike organic contaminants. They are nonbiodegradable and highly water solubile that facilitates their interactions and accumulation by living organisms, threatening human health as well as ecosystems. Furthermore, many of these heavy metals are known to have carcinogenic nature [1]. Thus, there is a high demand for 344effective removal and treatment of heavy metals from wastewater to protect the human population and the environment. Several heavy metals like Zn, Cu, Ni, Hg, Cd, Pb, As, and Cr are particularly important in the treatment of industrial wastewaters [2–4]. Various methods have already been utilized for the removal of harmful metal ions. These conventional methods like chemical precipitation, ion-exchange filtration, flotation, electrochemical treatment, reverse osmosis, membrane technologies, and evaporation [5–7] suffer from a major disadvantage, production of toxic chemical sludge, whose treatment becomes a costly affair and is not eco-friendly. Therefore, considerable attention has been devoted to study the removal of heavy metal ions from water by adsorption using eco-friendly materials in an environmentally safe level with cost-effectiveness [8].