Due to the scientific and technological progress, toxic metal contamination is a serious problem threatening human health. Heavy metal ions such as Pb(II), Cd(II), Hg(II) and Ni(II) are toxic and carcinogenic at even relatively low concentrations. They are not biodegradable and can accumulate in living organisms causing various diseases and disorders. Therefore, these heavy metals can be considered as one of the most toxic pollutants for water and wastewaters. Heavy metals are generally discharged to the environments via automobile emissions, mining activities, battery industry, fossil fuels, metal plating and electronic industries with diverse routes.