Environmental pollution as a consequence of the industrialization process, is one of the major problems that have to be solved and controlled. Heavy metals have become an ecotoxicological hazard of prime interest and increasing significance owing to their harmful effect on human physiology. Copper has been reported as one of the most widely used heavy metal in electrical industries. A number of technologies for the removal of heavy metal ions from aqueous solutions have been developed over the years. The most important of these techniques include chemical precipitation and filtration. However, all these techniques have their inherent advantages and limitations in application. The process of adsorption has become one of the preferred methods for removal of toxic contaminants from water as it has been found to be very effective, economical and simple.
The ability of natural zeolite (Clinoptilolite) to remove copper from aqueous solutions was studied in batch reactors. The effect of solution pH (1.00-6.00) on the removal of heavy metals was studied. The removal of Cu(II) using clinoptilolite reached 89.7 % , at ambient temperature, initial pH (5.5) and at the agitation speed of 300 rpm, while it was approximately 11.2 % at pH=1. The concentration of metal ions were measured by atomic absorption spectroscopy (AAS). Clinoptilolite was found to be effective for the removal of copper in batch reactors under all the tested conditions. The acidity of the aqueous solution influences the removal of copper by minerals. Isotherms for the adsorption of Cu(II) on clinoptilolite were developed and the equilibrium data fitted well to the Langmiur and Freundlich models.