g-C3N4/TiO2 Nanocomposites for Degradation of Ciprofloxacin under Visible Light Irradiation

The graphitic carbon nitride (g-C3N4), possessing the suitable band gap (2.7 eV), is benefit for TiO2 modification and improving photocatalytic efficiency for the degradation of organic pollutants under visible light irradiation. In this work, the g-C3N4/TiO2 nanocomposites were synthesized by using a simple sol-gel method. It was demonstrated that the hybridization between TiO2 nanoparticles and g-C3N4 was successfully formed. The DRS analysis showed that the addition of g-C3N4 improved the optical absorption of TiO2 in the visible region, and it means that more light energy could be absorbed for enhancing the photocatalytic activity. The g-C3N4/TiO2 nanocomposites showed superior photocatalytic performance for the degradation of ciprofloxacin (CIP) under visible light irradiation, compared with pure TiO2 and commercial P25 (Degussa). Moreover, radical trap experiment was carried out, which indicated that the hole acted as the main reactive species for the photocatalytic degradation of CIP. A possible photocatalytic mechanism of g-C3N4/TiO2 nanocomposite for the enhanced degradation of CIP under visible light irradiation was also proposed.