Adsorptive removal studies of lead(II) ions using functionalized silica

An adsorbent was prepared by the functionalization of 2-hydroxyacetophenone-3-thiosemicarbazone onto 3-aminopropyl silica by diazotation and characterized by Fourier transmission infra red spectrometry. The functionalized silica was evaluated for removal of lead(II) ions in aqueous solutions. The maximum adsorption capacity 385 mu g/g was obtained with an initial concentration of 1,000 mu g/L by the Langmuir isotherm. The results indicated that adsorption data could be fitted better by the Langmuir than the Freundlich isotherm. The adsorption kinetics followed pseudo-second-order reaction and the rate constants of kinetic model were calculated. The experimental results implied that functionalized silica has the potential to work as a good adsorbent for the removal of the heavy metals from contaminated water. This novel adsorbent was found to be easy to synthesize, simple, cost-effective and highly efficient and has potential application in the water purification field.