ZeoliteNaX Adsorbent for Recovery of Heavy Metal Ions

Abstract

The industrial waste water laden with heavy metal ions is one of the major culprits in polluting the environment. The natural process of transportation of metal ions from wastewater to soil results in accumulation of metal contaminants that severely affects the ecosystem. The heavy metal ions enter into streams, lakes, rivers and groundwater through industrial and social activity wastes or even from acidic rains. According to World Health Organization(WHO) the heavy metal ions of the most immediate concern to human beings are Chromium(Cr), Nickel(Ni), Lead(Pb), Copper(Cu), Mercury(Hg), Arsenic(As) and Zinc(Zn). According to CPCB(March,2012), permissible limits for Ni(II),Cr (VI), Pb(II) and Cu(II) are 3.0, 0.1, 0.1 and 3.0 mg/L respectively. The concentration of these ions should, therefore, be reduced in the effluent before its discharge on land or into water bodies. newline newlineThe adsorption technique is cost effective and efficient compared to the other alternate techniques therefore it gaining prominence. In the literature different adsorbents used for adsorption include Activated Carbon, Activated carbon from agricultural waste (such as baggase, coconut shell, rice husk etc.), Alumina, Synthetic Polymeric Adsorbents, Chitosan, Clay, Fly Ash, Algae and Zeolite etc. newlineZeoliteNaX was selected as an adsorbent for the recovery of heavy metal ions such as Lead, Copper, Nickel and Chromium from wastewater. The adsorption study was carried out in both the batch and the column mode to find out the effect of parameters such as contact time, pH, initial concentration, temperature, adsorbent amount. The removal efficiency and adsorption capacity of ZeoliteNaX for heavy metal ions such as Lead, Copper, Nickel and Chromium was studied. It was shown that the ZeoliteNaX could be used as an efficient and cost effective adsorbent for the removal of Pb (II), Cu (II), Ni (II) and Cr (VI) ions from aqueous solutions with maximum uptake of 14.22, 10.977, 8.85 and 6.414 mg/g for Pb (II), Ni (II), Cu (II) and Cr (VI) respectively.