Amine-grafted alumino-siloxane hybrid porous granular media: A potential sol-gel sorbent for treating hazardous Cr(VI) in aqueous environment

Amine grafted alumino-siloxane hybrid was processed first via sol-gel assisted in situ coagulation and poly-condensation reaction. Spherical granular media was then fabricated through nanocasting followed by self assembly techniques. Two kinds of hybrid granular sorbents namely aminated boehmite (A-HB) and boehmite/silica (A-HBS) were prepared and characterized for the chemical, structural and surface properties using FTIR, BET-surface area, SEM, and Zeta potential measurements. Cr(VI) adsorption efficiency of the resulted mesoporous sol gel hybrid sorbents was systematically carried out at varying pH, dosage, concentration, temperature and ionic strength. From the experimental data, the adsorption kinetics and isotherms were studied and verified with standard models such as Lagergren pseudo-first-order and pseudo-second-order kinetic models and Langmuir, Freundlich, Sips, Redlich-Peterson and Toth isotherm models. The adsorption efficiency of the hybrids was also compared with the already reported conventional sorbents from the literature. (C) 2013 Elsevier B.V. All rights reserved.