Adsorption of Co(II) and Mn(II) Ions on Mesoporous Silica SBA15 Functionalized with Amine Groups

Abstract

The adsorption characteristics of Co(II) and Mn(II) ions on mesoporous silica SBA15 were investigated. SBA15 was synthesized from the silicate precursor tetraethyl-orthosilicate (TEOS), and it was functionalized with ethylene-diamine-tetra-acetic-acid (EDTA) and N,N-dimethyl-acetamide (DMAC), which consists of the amine functional groups. It was also characterized by nitrogen adsorption–desorption analysis, element analysis (EA), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The adsorption capacities of EDTA functionalized SBA15 for Co(II) and DMAC functionalized SBA15 for Mn(II) in a single component system were found to be 10.12 mg/g and 6.8 mg/g, respectively. These values are about 10 times higher than that of as-synthesized SBA15. The adsorption isotherms and kinetics data were found to follow the Langmuir adsorption isotherm model and the Pseudo-second order kinetic model (r² > 0.99). After the 5 adsorption cycles, over 90% regeneration efficiency was achieved for the functionalized SBA15, which would be applied for recovery of the metals.