Novel magnetically separable g-C3N4/TiO2/CuFe2O4 photocatalyst for efficient degradation of tetracycline under visible light irradiation: Optimization of process by RSM

Herein, a novel magnetic visible-driven g-C₃N₄/TiO₂/CuFe₂O₄ nanocomposite with excellent photocatalytic performance was successfully prepared and employed for photodegradation of tetracycline. Several analysis including X-Ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), energy dispersive X-ray (EDX), Vibrating-Sample Magnetometer (VSM), and Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV–Vis DRS) were performed in order to study the structural, optical, magnetic, as well as morphological properties of nanocomposite. The optical band gap of g-C₃N₄/TiO₂/CuFe₂O₄ heterostructure was found to be red shifted to 2.45 eV from 3.15 eV for pure TiO₂. Enhanced separation of photoinduced electron-hole pairs and enhanced visible light absorption capacity of nanocomposite lead to a maximum tetracycline photodegradation efficiency. Response surface methodology (RSM) was used to investigate the influence four independent variables, including initial photocatalyst dosage (7–14 g/L), TC concentration (20–30 ppm), solution pH (5.5–7.5), and irradiation time (20–40 min), and optimize the TC degradation efficiency. The g-C₃N₄/TiO₂/CuFe₂O₄ nanocomposite was able to separate and recycle easily using an external magnetic field, and the results of reusability was shown its high stability after 5 cycles. Active species trapping experiments suggested that holes and hydroxyl radicals played a crucial role in the TC degradation process. Finally, a potential photocatalytic mechanism for photodegradation of TC was proposed.