Green and hydrothermal assembly of reduced graphene oxide (rGO)-coated ZnO and Fe hybrid nanocomposite for the removal of nitrate and phosphate

Abstract This study aimed to achieve an innovative, environmentally friendly, and effectual method for preparing a hybrid nanocomposite using reduced graphene oxide (rGO)-coated iron-doped zinc oxide (rGO/ZnO/Fe) to remove nitrate and phosphate from the reaction mixture. Prunus × yedoensis leaf extract was used as a reducer and was calcined at different temperatures (80 and 160 °C) for 24 and 48 h in a hydrothermal reactor. The physical characteristics of the rGO/ZnO/Fe composite nanostructure were studied by high-resolution transmission electron microscopy (HR-TEM). Elemental mapping and energy-dispersive X-ray spectroscopy (EDS) demonstrated the occurrence of elements, their distribution, and the magnitudes. The functional groups were confirmed by Fourier transform infrared spectroscopy (FTIR). The composite was further characterized using the Brunauer–Emmett–Teller (BET) technique, X-ray powder diffraction (XRD), and Raman spectroscopy. The composites treated at 80 °C for 24 h, 160 °C for 24 h, 80 °C for 48 h, and 160 °C for 48 h remove nitrate up to 82%, 86%, 92%, 96%, and phosphate up to 72%, 84%, 68%, 90%, respectively.