Comparative Adsorption of Pb2+on Nanostructured Iron-Zirconium Oxide with Fe-to-Zr Molar Ratio of 1:1 and 1:2:Thermodynamic and Kinetic Studies

Nanostructured iron-zirconium oxides (NIZOs), with Fe-to-Zr molar ratio of 1:1 and 1:2, have been found to show high adsorption efficiency toward Pb(2+)from aqueous solution. The NIZO was synthesized by the co-precipitation method and characterized in terms of XRD, TEM, SEM-EDX, BET surface area analysis, TGA, FT-IR spectroscopy and zeta potential measurement. The data of adsorption of Pb(2+)on the NIZO, under optimized condition of pH, Pb(2+)concentration, adsorbent amount, time and temperature, were fitted in Langmuir, Freundlich and Temkin adsorption model, and the data showed the best agreement with Langmuir model withR(2) = 0.990 and 0.994 for Fe/Zr molar ratio = 1:1 and 1:2, respectively. The thermodynamic studies showed that the adsorption of Pb(2+)on the NIZO proceeds spontaneously and exothermically through the involvement of weak van der Waals forces. Further, the adsorption of Pb(2+)on the NIZO was found to follow pseudo-second-order kinetics.

Automated summary

Nanostructured iron-zirconium oxides (NIZOs) exhibit high adsorption efficiency towards Pb(2+) from aqueous solution, following Langmuir model. The adsorption process is spontaneous, exothermic, mediated by weak van der Waals forces, and conforms to pseudo-second-order kinetics.