Photocatalytic Ozonation of 2,4-Dichlorophenoxyacetic Acid using LaFeO3 Photocatalyst Under Visible Light Irradiation

Abstract In this paper, LaFeO 3 nanoparticles were used as a visible light photocatalyst for efficient removal of 2,4-dichlorophenoxyacetic acid (2,4-D) with the assist of ozone. The pseudo-first-order kinetic rate constants of degrading 2,4-D removal in 60-PO/Vis in 1 h was 5.72 times as great as the sum of that when using LFO/O 2 /Vis and 60-Oz/Vis at the best concentration of ozone (60 mL/min). This improvement was attributed to the efficient synergistic effect between photocatalysis and ozonation triggered by LaFeO 3 . In PO/Vis, ozone facilitates the photo-generated electrons trapping and improves separation efficiency of photo-generated charges, which enhanced the yield of hydroxyl radical, so as to the degradation efficiency of organic pollutants. In addition, the effects of ozone concentrations on the photocatalytic ozonation processes were also studied. Moreover, we demonstrated the high stability and reusability of LaFeO 3 photocatalyst in photocatalytic ozonation process by circle experiment. Graphical Abstract Schematic illustration of the reaction mechanism of enhanced photocatalytic ozonation of 2,4-D by LaFeO 3 under visible light.