Photocatalytic degradation of diazinon under visible light using TiO 2 /Fe 2 O 3 nanocomposite synthesized by ultrasonic-assisted impregnation method

Abstract

Abstract Diazinon is one of the organophosphorus pesticides. It can threaten human and animal health, if stays in water and soil resources. Herein, the photocatalytic degradation of Diazinon under visible light was accomplished using TiO 2 /Fe 2 O 3 nanocomposite, which has been never employed for diazinon degradation. Firstly, TiO 2 /Fe 2 O 3 nanopowder was synthesized via ultrasonic-assisted impregnation method. To achieve this goal, TiO 2 nanoparticles were effectively dispersed in the solution. Then, Fe 3+ was impregnated on TiO 2 nanopowder under sonication process and calcined at 300 °C. The prepared photocatalyst was authenticated by XRD, EDX, FESEM, TEM, PL, and DRS analysis methods yielding following results: Anatase and maghemite crystalline structure of TiO 2 /Fe 2 O 3 nanoparticles, successful impregnation of Fe 2 O 3 on the surface of TiO 2 nanopowder, mean diameter size of 17 nm, extended absorption spectra of Fe 2 O 3 /TiO 2 nanocomposite in the visible region, and the better inhibition of electron and electron-hole recombination. Secondly, Kinetics of degradation was systematically optimized by multi variable central composite design based on response surface method. Degradation efficiency was highly affected by Diazinon dosage. The maximum experimental degradation efficiency was 95.07%. Optimum condition which was determined by software, included 0.1 g/L catalyst, 10 ppm Diazinon dosage, 45 min reaction time and 14 W/cm 2 light intensity and predicted 88.93% degradation efficiency with desirability of 0.873.