Design and synthesis of g-C3N4/(Cu/TiO2) nanocomposite for the visible light photocatalytic degradation of endosulfan in aqueous solutions

•Successful synthesis of g-C3N4/Cu/TiO2 composite as a photocatalyst.•High photocatalytic performance of the composite under visible light irradiation.•60% degradation of endosulfan in aqueous medium after 80 min irradiation.•Enhanced photocatalytic activity compared to pure g-C3N4 and Cu/TiO2. The g-C3N4/Cu/TiO2 (graphitic-carbon nitride/copper/titanium dioxide) nanocomposite as a photocatalyst was developed to degrade endosulfan, a very poisonous pesticide, in an aqueous medium under visible light irradiation. The structure, morphology, and optical properties of the synthesized nanocomposite were determined using SEM, XRD, FT-IR, DRS, EDX, and PL. The obtained results showed that incorporating the Cu and TiO2 molecules onto g-C3N4 led to enhance absorption ability in the visible region, as well as improved the separation of photo-excited electron–holes. Some operational factors such as initial pesticide concentration, pH, and the presence of anions were studied in the photocatalytic degradation of endosulfan. The 60% photocatalytic performance was achieved by 80 min irradiation of the endosulfan solution, which was three times higher than pure g-C3N4. The improved photodegradation efficiency probably arose from the synergistic effect between three components of the composite photocatalyst.