Abstract

Landfill leachate is one of the most contaminated waste types, which has created excessive health and environmental concerns due to the widespread use of urban landfill for final wastes disposal. One of the important environmental parameters in waste leachate is soluble heavy metals. Presence of heavy metals due to biological accumulation property of these materials endangered the health of living creatures especially human. In this study one kind of natural zeolite called clinopteliolit in both form of unmodified (crude) and modified by hexadecyl trimethyl ammonium- bromide surfactant (HDTMA-Br) were used for removing the lead and cadmium metals. Adsorption experiments were performed in unsteady flow reactors and the impact of contact time and concentration variables were examined. Also, different models of absorption isotherms and kinetics of uptake reactions such as degree, were studied.In this study approved that the unmodified zeolite has the limited ability in lead and cadmium metals uptake, But in comparison to unmodified zeolite, modified zeolite with hexadecyl trimethyl ammonium- bromide show significant capacity in adsorption of these metals and compared between these two metals, cadmium was adsorbed in higher efficiency than lead. Adsorption efficiency of Pb with initial concentration of 1.61 mg / l equals to 71.64 and the Adsorption efficiency of cadmium with initial concentration of 1.98 mg / l 75.2 obtained in this method. the results of reaction kinetics showed that rate of cadmium adsorption by modified zeolite with surfactant is more rapid than rate of lead adsorption. © IDOSI Publications, 2011.