Synergistic effect of graphene oxide based nitrogen-doped nano-titanium oxide for effective adsorption and photo catalysis of dibutyl phthalate and organic pollutants from water

Graphene oxide loaded N-TiO2 was prepared by one step colloidal blending approach. The prepared material was characterized by FT-IR (Fourier transform infrared spectroscopy), XRD (X-ray diffraction), SEM (Scanning electron microscopy), EDS (Electron dispersive spectroscopy), XPS (X-ray photoelectron spectroscopy) and BET (Brunauer–Emmett–Teller). Employing Tauc’s method, the optical band gaps are investigated, demonstrating that the composite material's spectrum responses were expanded to the visible-light region and show notable band gap energy reduction from 2.9 to 2.1 eV. The effects of different pH values and contact periods were thoroughly examined on the removal activity of GO/N-TiO2 for methylene blue (MB), rhodamine-B (RB), dibutyl phthalate (DBP), and 4-chlorophenol (4-CP). An enhanced removal ratio of 99.6%, 92.4%, 99.4%, and 67.7% was achieved for MB, RB, DBP, and 4-CP, respectively, by GO/N-TiO2 after 180 min of illumination. The exceptional effectiveness of the GO/N-TiO2 composite in the visible range may be due to its lowered band gap. Furthermore, the quenching tests were conducted to understand the removal mechanism in better manner, and the results showed that the most reactive species in this system were hydroxyl, superoxide radicals, and holes, which were confirmed by trapping studies. Additionally, a potential mechanism for the elimination of different contaminants by composite material was also proposed and discussed.