Study of Adsorption process of Zinc Ions from Aqueous Solutions by Almond Shell Powder

The problems of the ecosystem are increasing with developing technology. Heavy metal pollution is one of the main problems [1]. Industrial waste water represents the main source of environmental pollution with heavy metals, e.g. Cu, Pb, Fe, Cd, Mn, etc [2]. As a result, it is necessary to remove of heavy metals from aqueous environment, by a simple and cost-effective method[3]. The main goal of this research study was the removal of Zn(II) from aqueous solutions using almond shell powder. The different parameters such as solution pH, almond shell powder and Zn(II) concentrations, contact time, ionic strength and temperature were studied to determine the influence of these parameters on the adsorption capacity of the Zn(II) from water. Also, kinetic studies and equilibrium isotherms were investigated, too. About 90 % of Zn(II) ions were removed from aqueous solutions at pH 5 after 50 min contact time and at room temperature (~25º). Results show that removal efficiency of the Zn(II) decreased by increasing Zn(II) concentration and ionic strength of solution and increased by increasing the concentration of almond shell powder. The equilibrium isotherm was better described by Freundlich model . The kinetic studies indicate the adsorption of Zn(II) onto almond shell powder is followed a pseudo-second order kinetic.