Melamine modified P25 with heating method and enhanced the photocatalytic activity on degradation of ciprofloxacin

The graphitic carbon nitride (g-C ₃ N ₄ ), as one photocatalyst which possess the suitable band gap, is better for modified TiO ₂ and enhanced photocatalytic degradation of organic pollutants. In this work, the g-C ₃ N ₄ /TiO ₂ were successfully prepared via directly calcined the mixture of melamine and P25. The as-prepared g-C ₃ N ₄ /TiO ₂ photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and high resolution electron microscopy (HRTEM), Raman and Fourier transform-infrared spectroscopy (FT-IR). The photocatalytic performances of g-C ₃ N ₄ /TiO ₂ composites were investigated by degradation of ciprofloxacin. The results showed that the g-C ₃ N ₄ and P25 were successfully composited, and the bond of C-N was well formed, the calcined temperature for as-prepared photocatalysts and the ratio of melamine and P25 were important to the degradation rate of ciprofloxacin. When the mixture of melamine and P25 with 1:2, and calcined temperature at 600 °C, the degradation rate of ciprofloxacin could reach 95% in 60 min. The enhanced photocatalytic performances could be mainly attributed to the suitable band gap structure with heterojunction of CN-P25. Finally, the possible transferred processes of photoelectrons and photoholes were proposed.