Novel Pb(II) ion-imprinted materials based on bis-pyrazolyl functionalized mesoporous silica for the selective removal of Pb(II) in water samples

Abstract

Three highly efficient adsorbents Pb-IIMS-SBA-15, Pb-IIMS-MCM-41 and Pb-IIMS-FDU-12 for Pb(II) were prepared by grafting the functional monomer 4-(di (1H-pyrazol-1-yl) methyl) phenol (DPP) on corresponding mesoporous silicas with Pb(II) as temple. All these three Pb(II) ion-imprinted mesoporous silica (Pb-IIMS) were characterized by Fourier transform-infrared spectroscopy (FT-IR), solid-state 29Si and 13C NMR spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), N2 adsorption–desorption analysis and small angel X-ray diffraction (XRD). The adsorption experiments revealed three Pb-IIMS all possessed considerable adsorption performance for Pb(II), their adsorption profiles obeyed pseudo-second-order kinetics and Langmuir isotherm model. Compared with their corresponding non-imprinted materials, three Pb-IIMS displayed satisfactory selectivity to Pb(II) over seven competing metal ions. Among them, Pb-IIMS-MCM-41 particularly owned outstanding adsorption performance and selectivity, the maximum adsorption capacity as high as 344.8 mg g−1, as well as excellent reusability through twelve adsorption-desorption cycles. Additionally, Pb-IIMS-MCM-41 was employed as packing material to construct a solid-phase extraction column for detection of Pb(II), which exhibited detection limit of 0.015 μg L−1, then method was successfully applied to the removal and determination of trace Pb(II) in practical water samples.