Hydrothermal synthesis and crystal structure of a new organic-inorganic magnesium complex for the removal of tetracycline

Abstract

A new organic-inorganic complex, [Mg(phen)(H2O)4]bdc. phen. H2O (1) where phen = 1, 10-phenanthroline and bdc2- = isophthalato was synthesized by hydrothermal method. Complex 1 has been characterized by elemental analysis, thermal gravimetric analysis (TGA), differential thermal analysis (DTA) and single-crystal X-ray diffraction (SCXRD). The results of SCXRD analysis revealed that complex 1 crystallizes in space group P21/n of a monoclinic system. In the crystal packing of complex 1 there are high amounts of strong O–H···O and O–H···N hydrogen bonds, weaker C–H···O and C–H···π hydrogen bonds and π···π stacking interactions. The MgO/SiO2 nanocomposite was successfully synthesized by thermal decomposition of complex 1 at 550°C. The Fourier-transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett –Teller (BET) specific surface area were used to characterize the structure and morphology of MgO/SiO2 nanocomposite. The adsorption of tetracycline (TC) by nanocomposite of MgO/SiO2 was studied and the influencing parameters including ionic strength, pH value, initial concentration of TC and temperature were investigated. It was found that the adsorption of TC onto MgO/SiO2 is favorable and reaches a maximum value at pH of 6. The electrostatic interaction between TC molecule and the nanocomposite is probably the main adsorption mechanism. The current work shows that the nanocomposite of MgO/SiO2 acts as a good case for the removal of TC due to high removal efficiency and excellent recycling capability.