Synthesis of V Doped Ca Bismuthate Nanoflakes for Photocatalytic Removal of Crystal Violet Dye

Abstract

Background: Crystal violet dye (CV) can cause severe eye irritation and cancer due to its adsorption, ingestion, and inhalation effect. Therefore, CV in wastewater systems has severe risks to human health and environmental safety. It is essential to remove CV before it is discharged into the environment. Methods: Vanadium-doped calcium bismuthate nanoflakes with the vanadium ratio of 1 wt.%, 3 wt.%, 5 wt.%, and 10 wt.% have been synthesized by a simple hydrothermal route using sodium vanadate as the vanadium raw materials. The obtained vanadium-doped calcium bismuthate products were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and solid diffuse reflection spectrum. Results: XRD patterns show that the vanadium in the doped nanoflakes exists as triclinic Bi3.5V1.2O8.25 and monoclinic Ca0.17V2O5 phases. SEM observations show that the morphology of the products is closely related to the vanadium mass ratio. The morphology changes from the nanoflakes to irregular nanoparticles with increasing the vanadium mass ratio. The bandgap of the vanadium-doped calcium bismuthate nanoflakes decreases to 1.46 eV and 1.01 eV when the doped vanadium mass ratio reaches 5 wt.% and 10 wt.%, respectively. The photocatalytic performance for the CV removal can be greatly enhanced using 5 wt.% and 10 wt.% vanadium-doped calcium bismuthate nanoflakes, respectively. Increasing the irradiation time, vanadium mass ratio, and dosage of the nanoflakes, the photocatalytic activity for the CV removal can be improved. Conclusion: A total of 10 wt.% vanadium-doped calcium bismuthate nanoflakes have the best photocatalytic performance for CV removal. Vanadium-doped calcium bismuthate nanoflakes exhibit great application potential for the removal of organic pollutants.