Investigation of Lead Retention onto Zeolite As Influenced by Nickel and Copper Ions

ABSTRACT: A laboratory trial was conducted to investigate lead (Pb) retention characteristics onto natural zeolite in the absence or presence of nickel (Ni) or copper (Cu) as competitor ions. Zeolite was equilibrated with different concentrations of Pb in single system without competitor ions or along with Ni or Cu in bi-solue systems. Pb adsorption data for single and bi-solute systems showed relatively desirable fits to the Langmuir and the Freundlich models as evidenced by the relatively high values of coefficients of determination (R2) and low values of standard errors of estimate (SE). The highest monolayer adsorptrion maxima, qm coefficient, was observed under single system condition where no competitor ion was available. Under bi-solute conditions the qm coefficient decreased. The amount of decrease in qm coefficient in the presence of competitor ions was more considerable in the presence of Ni as compared to Cu. The lowest quantity of the bonding energy coefficient, KL, for Pb was observed under single system in the absence of competitor ions. In the presence of competitor ions the quantity of KL coefficient increased demonstrating increase in the Pb bonding energy in the presence of a competitor ion. The amount of increase in KL was higher in the presence of Cu as compared to Ni. Our results demonstrated high adsorption capacity of zeolite for the removal of Pb from the solution. Surprisingly, the KF coefficient, the amounts of Pb adsorbed by zeolite at the equilibrium concentration of unity, was the least for the single system, in the absence of competitor ions. In the presence of competitor ions the KF coefficient increased. The amount of increase was higher in the presence of Cu as compared to Ni. High adsorption capacity, being natural, abundant and inexpensive make zeolite an appropriate adsorbent for the removal of Pb from different waste systems polluted with this metal.