Synthesis of ordered mesoporous SBA-15 and its adsorption of methylene blue

Abstract

The removal of methylene blue (MB) dye pollutant from synthetic wastewater onto mesoporous SBA-15 was studied in batch adsorption systems. The characterization for the prepared adsorbent such as: X-ray diffraction (XRD), scanning electron microscopy (SEM), BET surface area and Fourier transform infrared (FTIR) spectroscopy was achieved. The experiments were carried out to measure the adsorption capacity as a function of contact time, initial concentration (40-110 mg/L), pH (3-11) and adsorbent dose (0.1-2.3 g/L). The equilibrium of the process was achieved within 20 min. Adsorption isotherms were fitted with the Langmuir, Freundlich and Temkin models. The equilibrium data were better represented with Langmuir Isotherm model. The kinetics of the MB sorption on SBA-15 was examined by using pseudo-first and pseudo-second order kinetics models. The kinetics analysis showed that the overall adsorption process was successfully fitted with the pseudo-second-order kinetic model. Good linearization of the data was observed for the initial phase of the reaction in accordance with expected behavior of intraparticle diffusion as the rate-limiting and rate-controlled step. SBA-15 can be effectively recovered by calcinations and reused fourteen times in batch system without significant loss in removal of methylene blue from aqueous solution.