Application of Natural Zeolites in Removal of Heavy Metals from Industrial Wastewaters of Iron and Steel Production Plants

Industrial wastewater of Iron and Steel production plants contain a variety of heavy metals such as Pb, Cd, Hg, Cu, Ni, Zn and Cr and have a high potential of contaminating the receiving water bodies. The aim of this research was to investigate the performance of natural zeolites as low cost adsorbents in removing heavy metals from industrial wastewater of Zob Ahan company. Concentrations of Pb, Cd and Zn in industrial wastewater from agglomeration unit were measured to be 7, 1.5 and about 1.5 times higher than the standard concentrations for irrigation. Results obtained by conducting batch adsorption tests indicated that natural zeolites can adsorb and remove heavy metals. It was also concluded that Freundlich isotherm model was successful in describing the experimental results. Results from Column laboratory test showed that removal efficiencies of natural zeolite column for removal of Pb, Cd, and Zn were 45%, 58%, and 42% , respectively.