Synthesis of Nano-NaX Zeolite by Microwave Heating Method for Removal of Lead, Copper, and Cobalt Ions from Aqueous Solution

Nano-NaX zeolite was synthesized by the microwave heating method and its application for the removal of heavy metal ions such as lead [Pb(II)], copper [Cu(II)], and cobalt [Co(II)] from aqueous solutions was investigated. The effect of adsorption variables including contact time, initial concentration, and temperature on adsorption efficiency by the nano-NaX zeolite was studied in a batch mode. The prepared NaX zeolite nanoparticles were characterized by the X-ray powder diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering (DLS), Brunauer-Emmett-Teller (BET), and X-ray fluorescence (XRF) analysis. Based on the results, the homogeneous zeolite nanoparticles with the average diameter and surface area of 95nm and 536m2g-1, respectively, were obtained. The adsorption selectivity of lead, copper, and cobalt ions by the nano-NaX zeolite was in the order of Pb(II)>Cu(II)>Co(II). The pseudo-first-order, pseudo-second-order, and double exponential kinetic models were used to describe the kinetic data. The equilibrium data were also analyzed using isotherm models. The maximum monolayer capacity of the NaX zeolite was found to be 461.61, 144.9, and 125.3mgg-1 for the Pb(II), Cu(II), and Co(II) ions, respectively, at a temperature of 313K. Finally, the thermodynamic parameters were evaluated to obtain the nature of the adsorption process by the nano-NaX zeolite. The results achieved were comparable with other prepared zeolites but with the advantage of requiring a much shorter preparation time.