Facile preparation of MgO-loaded SiO2 nanocomposites for tetracycline removal from aqueous solution

The MgO-loaded SiO2 nanocomposites were successfully synthesized via a facile precipitation and calcination method, and used for the elimination of antibiotics from aqueous solution. Multiple techniques such as X-ray photoelectron spectroscopy (XPS), fourier transform infrared (FT-IR), transmission electron microscope (TEM), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) were employed to characterize the structure and morphology of the obtained nanocomposites. The effects of the loading content of MgO, initial solution pH and temperature on the adsorption performance of MgO-loaded SiO2 nanocomposites were assessed by removing tetracycline from aqueous solution. It was found that 50% MgO-loaded SiO2 exhibited excellent adsorption performance towards tetracycline with a removal rate above 80% in a wide pH range of 4-10, which was much higher than that of individual MgO and mesoporous SiO2. The nanocomposite possessed higher specific surface area (356.02 m(2)g(-1)) and smaller MgO particles compared with pure MgO (81.02 m(2)g(-1)), which can provide more active sites, thus enhancing the adsorption performance towards tetracycline. The electrostatic interaction and inner-sphere complexation between nanocomposites and tetracycline molecules were considered to play important roles in the adsorption process of tetracycline. The as-synthesized nanocomposites as promising adsorbents have a potential application in the removal of antibiotics from aqueous solution. (C) 2019 Elsevier B.V. All rights reserved.