Removal of heavy metals (Zn, Cr, Pb, Cd, Cu and Fe) in aqueous media by calcium carbonate as an adsorbent

Abstract

The adsorption of heavy metals ions in continuous flow column having calcium carbonate as adsorbent was carried at laboratory scale. The aqueous solutions of heavy metal passed through column having bed of precipitated CaCO3. The concentration of each metal was determined by atomic absorption spectrometer before and after treatment. The significant decrease in the concentration of all metal ions was observed after treatment. The initial concentration of metals such as Zn 2+ , Cr 3+ , Pb 2+ , Cd 2+ , Cu 2+ and Fe 3+ were 195, 156, 621, 342, 190 and 168 mg/L which were reduced up to the level of 0.0089, 0.1390, 0.3510, 0.0390, 0.0242 and 0.3397 mg/L, respectively in treated samples. This significant removal of heavy metal ions indicates a remarkable efficiency of calcium carbonate as adsorbent. The adsorption capacity of calcium carbonate was calculated, which were found 400-1500 mg/g, while the effect of initial metal ion concentrations on the adsorption process was not pronounced. It is concluded that this treatment method may holds good in order to reduce metals ions concentration in industrial effluents.