Sonophotocatalytic treatment of diazinon using visible light‐driven Ce:Cu‐1,4‐BDOAH2 photocatalyst in a batch‐mode process: Response surface methodology and optimization

Abstract

Cu–1,4‐benzenedioxyacetic acid (Cu‐1,4‐BDOAH2) with a narrow band gap (2.52 eV) was synthesized and doped with Ce to afford Ce:Cu‐1,4‐BDOAH2 as an efficient photocatalyst with narrower band gap (2.39 eV). The prepared Cu‐1,4‐BDOAH2 and Ce:Cu‐1,4‐BDOAH2 were characterized using Fourier transform infrared, energy‐dispersive X‐ray, diffuse reflectance spectroscopies, scanning electron microscopy and X‐ray diffraction. The sonophotocatalytic degradation of diazinon was carried out in a batch‐mode reactor using visible light‐driven Ce:Cu‐1,4‐BDOAH2 photocatalyst as well as ultrasonic irradiation. The narrow band gap of the photocatalyst means that it can be activated under visible light illumination. The effects of operational parameters such as initial diazinon concentration (5–25 mg l−1), pH (2–10), photocatalyst dosage (10–30 mg) and irradiation time (10–30 min) on the sonophotocatalytic degradation efficiency were investigated using central composite design under response surface methodology. The optimization process was studied using desirability function and the results indicated 99.8% degradation, which was obtained at optimum values of 25 mg l−1, 6, 20 mg and 20 min for the initial concentration of diazinon, pH, photocatalyst dosage and irradiation time, respectively. Reusability experiments of Ce:Cu‐1,4‐BDOAH2 photocatalyst showed that it is quite stable with excellent catalytic activity even after five cycles.