Photocatalytic Removal of Metribuzin Using Titanium Dioxide/Silver Nanocomposite

 In the present study, titanium dioxide/silver nanocomposites (TiO2/Ag) were synthesized by sol-gel method and their performance for photocatalytic removal of metribuzin was compared with commercial TiO2 catalysts P25 Degussa.

The synthesized nanocomposites were evaluated using X-ray diffraction spectroscopy (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray analysis (EDX). The effect of operating parameters including reaction time (0-240 minutes), pH (9-4), catalyst dose (0.005-0.015 g), temperature (10-60 ºC), visible light and UV light radiation, concentration Initial metribuzin (10-25 mg/L), the catalyst effect in the dark, and the amount of silver in TiO2/Ag nanocomposites (0.10-7% by weight) were investigated on the photocatalytic removal of metribuzin from artificial and real aqueous solutions.

Laboratory investigations showed that TiO2/Ag nanocomposite containing 10% by weight of silver, reaction time of 120 minutes, pH equal to 6, catalyst mass of 0.013 g, and initial concentration of 10 mg/L metribuzin are the best properties to maximize the removal of metribuzin in the presence of UV light. The obtained results showed that the synthesized TiO2/Ag nanocomposite has a higher potential in the degradation of herbicides compared to the commercial TiO2 nano-catalyst. In addition, the proposed method was used to remove metribuzin injected into the water of the Karun and Zohreh rivers and the wastewater of the sugarcane factory under optimal conditions, and successful results were obtained. Also, the results of using and regenerating the titanium dioxide/silver catalyst three times to remove metribuzin show the high efficiency of this photocatalyst in removing metribuzin from water samples. Comparing the methods available in the literature for the removal of metribuzin with the present method showed that the proposed method is better or comparable to the reported methods.