Removal of Toxic/Heavy Metal Ions Using Ion-Imprinted Aminofunctionalized Silica Gel

The investigation reports the preparation and evaluation of Cr(III) and Fe(III)-imprinted amino-functionalized silica gel adsorbents (APTS-Cr(III)-Si and APTS-Fe(III)-Si) for selective solid- phase extraction of Cr(III) and Fe(III), respectively, from aqueous solutions. The adsorbent materials were prepared by a surface imprinting technique using 3-aminopropyltrimethoxysilane as the surface modifying ligand. The effects of solution pH, sorption time, temperature, and initial metal ion concentration upon adsorption characteristics were investigated. The adsorption isotherms for Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) were evaluated and the thermodynamics of the adsorption processes were correlated. By optimizing the parameters, the synthesized materials could be used successfully for selective removal of trivalent cations from a mixture of cations in dilute aqueous solution.