Removal of methylene blue using tungsten(VI)-oxide immobilized on commercial PVC in the presence of simulated solar radiation

In this paper, the efficiency of six tungsten oxide/polyvinyl chloride (WO 3 /PVC) composites with a different mass ratio of WO 3 to PVC (1, 1.75, 2.5, 3.75, 5 and 7.5%) for methylene blue ( c 0 = 2.45 × 10 −2 mM) removal in the presence/absence of simulated solar radiation was investigated. The composites were used in the form of tablets with a diameter of 5 mm and a thickness of 2 mm. The optimal mass ratio of WO 3 toward PVC, in the presence of the simulated solar radiation, was 2.5%, with the highest total removal efficiency of 57.7% after 30 min. The adsorption and photodegradation efficiencies were determined by the difference in relation to the total removal efficiency. The methylene blue removal kinetics were monitored by UV/Vis spectrophotometry, and also, the chemical oxygen demand (COD) removal efficiency was determined. The photocatalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV/Vis diffuse reflectance (UV/Vis DRS), and Raman spectroscopy. Finally, for the most efficient 2.5%WO 3 /PVC composite, the possibility of photo-cleaning and reusing tablets was also examined. The possible photodegradation mechanism of methylene blue dye with (WO 3 )/PVC was assumed using the scavenger test. Graphical abstract