Removal of Ni(II), Cd(II), and Pb(II) from a ternary aqueous solution by amino functionalized mesoporous and nano mesoporous silica

In the present study, the application for the removal of Ni(II), Cd(II) and Pb(II) ions from aqueous solution by using mesoporous silica materials, namely, MCM-41, nanoparticle of MCM-41, NH₂-MCM-41 (amino functionalized MCM-41) and nano NH₂-MCM-41 was investigated. Suitable adsorbents preparation techniques were developed in the laboratory. The effects of the solution pH, metal ion concentrations, adsorbent dosages, and contact time were studied. It was found that NH₂-MCM-41 showed the highest uptake for metal ions in aqueous solution. The results indicated that the adsorption of Ni(II), Cd(II) and Pb(II) ions on the surface of the adsorbent was increased with increasing solution pH. The experimental data were analyzed using the Langmuir and Freundlich equations. Correlation coefficients were determined by analyzing each isotherm. It was found that the Langmuir equation showed better correlation with the experimental data than the Freundlich. According to the parameters of the Langmuir isotherm, the maximum adsorption capacity of NH₂-MCM-41 for Ni(II), Cd(II) and Pb(II) was found to be 12.36, 18.25 and 57.74 mg/g, respectively. The kinetic data of adsorption reactions and the evaluation of adsorption equilibrium parameters were described by pseudo-first-order and pseudo-second-order equations. The synthesized solid sorbents were characterized by Fourier transform infrared (FT-IR) spectrometry, X-ray diffraction (XRD), scanning electron microscopy (SEM) and nitrogen sorption measurements.