Schiff base-functionalized mesoporous silicas (MCM-41, HMS) as Pb(ii) adsorbents

Abstract

Three Schiff base-functionalized mesoporous silicas: MCM-41@salen, HMS-C12@salen and HMS-C16@salen have been synthesized by a post-synthetic grafting strategy and their sorption capacities toward Pb(ii) from synthetic aqueous solutions have been assessed. FTIR spectra, TG/DSC analyses, X-ray powder diffraction, X-ray photoelectron spectroscopy (XPS), N2 adsorption isotherms and HRTEM micrographs were used to characterize the novel functionalized mesoporous silicas. The novel adsorbents have been tested for their capability in the remediation of synthetic aqueous systems containing Pb(ii). The Langmuir maximum values of sorption capacities of these adsorbents toward Pb(ii) are: 138.88 mg Pb(ii) per g MCM-41@salen, 144.92 mg Pb(ii) per g HMS-C12@salen, and 181.81 mg Pb(ii) per g HMS-C16@salen, therefore, the functionalized silicas (MCM-41@salen, HMS-C12@salen, HMS-C16@salen) could be used as effective adsorbents of Pb(ii) ions from wastewater.