Keywords: bichromate removal, adsorption thermodynamics, adsorption isotherms, adsorption kinetics, nano SBA–15, amine functionalised
Application of amine–functionalised nano SBA–15 for removal of bichromate from aqueous solutions
In this research, molecular sieve SBA–15 was synthesised and functionalised with 3–aminopropyltrimethoxysilane (N–silane) and [1–(2–aminoethyl)–3–aminopropyl] trimethoxysilane (NN–silane). The materials were characterised by X–ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FT–IR), and thermogravimetric analysis methods (TGA). The Brunauer–Emmett–Teller (BET) surface area of the samples was also measured. Bichromate adsorption behaviour of the resultant adsorbents was examined by a batch wise method. The effect of several variables such as contact time, pH, anion concentration and temperature on the adsorption capacity was studied and optimised. The adsorption results analysed by Freundlich and Langmuir isotherm models showed that the data was fitted by the Langmuir isotherm. Thermodynamic studies indicated that the adsorption process was endothermic and spontaneous in nature.