Silica-coated magnetic Fe3O4 nanoparticles as efficient nano-adsorbents for the improvement of the vapor-phase adsorption of benzene

Abstract

This study focused on the synthesis of silica-coated magnetic Fe3O4 (Fe3O4@SiO2) nanoparticles and their application for the improvement of the vapor-phase adsorption of benzene. The magnetic Fe3O4@SiO2 nanoparticles were synthesized according to the co-precipitation method, while their characterization was performed using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) surface area analyses. The experimental parameters were optimized to achieve the maximum adsorption capacity for the vapor-phase benzene by Box-Behnken design (BBD) under response surface methodology (RSM). The magnetic Fe3O4@SiO2 nanoparticles adsorbed 197.50 mg/g of the vapor-phase benzene under the following optimum conditions: 39.48 min residence time, 14.21 ppm initial benzene concentration and 26.51°C temperature. The Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were used to evaluate the adsorption equilibrium data, and the results were found to be well fitted to the D-R model. The kinetic data obeyed the pseudo-second-order kinetic model for the vapor-phase adsorption of benzene by magnetic Fe3O4@SiO2 nanoparticles. This study demonstrated the application potential of magnetic Fe3O4@SiO2 nanoparticles as promising low-cost nano-adsorbents for the vapor-phase adsorption of benzene.