Removal of Pb (II) from aqueous solution using hydrotalcite-like nanostructured material

Novel nanostructured hydrotalcite (HT) adsorption medium was prepared and its ability to remove Pb(II) from aqueous solution was demonstrated. The media was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscope (TEM) and Themogravimetric Analysis (TGA). Batch adsorption was chosen in which changes in solution pH, initial concentration and temperature were the main variables. In addition, the adsorption of Pb(II) in binary component systems was explored. Results reveal that Pb(II) adsorption was rapid and favoured at increased temperature and pH. It was observed, in comparison with single component system (Pb only), that the presence of co-ions reduces the Pb(II) adsorption suggesting a competitive adsorption at the water-hydrotalcite (HT) interface. The kinetic data fitted well to Ho pseudo second order model while the equilibrium data were satisfactorily described by the Langmuir isotherm. The Langmuir maximum adsorption capacity of Pb(II) at pH 6.0 was found to be 333 mg/g at 298 K and 500 mg/g at 308 K and 318 K. From the uptake values, this study reveals that nanostructured HT is an effective adsorbent for the removal of Pb(II) from aqueous solutions.