Photocatalytic dye degradation using BiVO4–paint composite coatings

Abstract

Bismuth vanadate (BiVO₄)–paint composites coated on the aluminium sheet surface were fabricated with different BiVO₄ amounts (0, 20, and 40 wt%) in paint. The degradation capability of the methylene blue (MB) dye using the BiVO₄–paint coated sample was explored. The impact of BiVO₄ content on the dye degradation performance was analyzed. The fabricated materials were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). XRD confirmed the existence of the BiVO₄ crystalline phase in paint. The elemental composition of the sample was determined using X-ray electron diffraction spectroscopy (EDS) inbuilt in SEM. The absorption spectra of BiVO₄ was determined using an UV-Vis-NIR spectrophotometer. As the content of BiVO₄ in the BiVO₄–paint sample increases, there is an increase in the dye degradation efficiency. The 40 wt%-BiVO₄–paint sample exhibited an ∼72% dye degradation efficiency as compared to the 0 wt%-BiVO₄–paint sample (∼27%) in a duration of 240 min of the photocatalysis experiment. The photocatalytic MB dye degradation is in accordance with the pseudo-first-order kinetics attaining the largest k value of 0.00524 min⁻¹. Photocatalytically treated water after the photocatalysis experiment falls in the moderate phytotoxicity level. A germination index study was done using Vigna radiata seeds.