Adsorption of Fe(II) Ions from Aqueous Solution Using Silica-Supported Organic–Inorganic Hybrid Sorbents

Abstract

A silica-supported organic–inorganic hybrid sorbents were prepared by sol–gel method and characterized by Fourier transmission infrared spectroscopy, scanning electron microscopy with energy dispersive spectrometry and thermal analysis. The adsorption behaviors of Fe(II) ions onto the hybrid sorbents from aqueous media had been investigated. The adsorption capacity of hybrid sorbents for Fe(II) ions was 90.7 mg g−1. Adsorption equilibrium of Fe(II) ions was achieved within 30 min of contact time. Solution pH had a minor effect on Fe(II) ions adsorption in the range of pH 3–6. The highly selective binding of the hybrid sorbents for Fe(II) ions with respective to other competitor ions (such as Cd(II), Zn(II), Co(II), Ni(II), and Pb(II) ions) was due to the high complexation affinity between Fe(II) ions and cyano groups. The adsorption/desorption cycle of hybrid sorbent could be up to three times. Experimental data revealed that Langmuir isotherm and pseudo–second–order models give best fit for Fe(II) ions adsorption with high correlation coefficients (>0.99). The calculation of thermodynamic parameters showed that the adsorption of Fe(II) ions on the hybrid sorbents was an exothermic and spontaneous process. These results confirmed that the hybrid sorbent could be a potential sorbent for the removal of Fe(II) ions from aqueous solutions.