Synthesis of novel zeolitic imidazolate framework (ZIF-67) – zinc oxide (ZnO) nanocomposite (ZnO@ZIF-67) and potential adsorption of pharmaceutical (tetracycline (TCC)) from water

Abstract

• Novel zeolitic imidazolate framework (ZIF-67) – zinc oxide (ZnO) nanocomposite (ZnO@ZIF-67) was synthesized. • The TCC adsorption process follows the Langmuir isotherm model. • The TCC removal obeys the pseudo-second-order kinetic model. • Maximum removal efficiency for TCC were 84.9%. • ZnO@ZIF-67 nanocomposite is an acceptable adsorbent for the removal of pharmaceutical. Herein, novel zeolitic imidazolate framework (ZIF-67) – zinc oxide (ZnO) nanocomposite (ZnO@ZIF-67) was synthesized with different amounts of ZnO (0.03, 0.05, and 0.09 g denoted as ZnOZ (0.03), ZnOZ (0.05), and ZnOZ (0.09), respectively. ZIF-67 and ZnOZs composites were synthesized at room temperature. The synthesized materials including ZIF-67, ZnO, ZnOZ (0.03), ZnOZ (0.05), and ZnOZ (0.09) were characterized by FTIR (Fourier-transform infrared spectroscopy), SEM (scanning electron microscopy), EDX (Energy-dispersive X-ray spectroscopy), XRD (X-ray powder diffraction), and BET (Brunauer-Emmett-Teller) analyses and used to remove tetracycline (TCC) as a pharmaceutical pollutant from water. The effect of various parameters including pH, contaminant initial concentration, adsorbent dose, contact time, and temperature from the aqueous medium was also investigated. The adsorption data showed that the TCC removal followed the Langmuir isotherm and pseudo-second-order kinetics. In addition, thermodynamic data indicated that TCC adsorption was a spontaneous and endothermic reaction. It could be concluded that ZnO@ZIF-67 nanocomposite was an acceptable adsorbent for the removal of pharmaceutical contaminant from aqueous media.