Solution volume effect of photodegradation by 1-D WO₃ nanorods via microwave-assisted solvothermal heating under the UV irradiation

The 1-D nanorods of WO₃ was synthesized by solvothermal-assisted microwave system. These nanorods was employed as photocatalysts in the photodecomposition reaction of methyl orange under the UV light. The powder was characterized by XRD, SEM and TEM. UVVisible diffuse reflection spectroscopy was used to measure the degradation efficiency. Different total solution volumes ranging between 400-1000 mL were responsible for the change in organic pollutants' photocatalysis efficiency. Furthermore, the effect of changing the concentration of methyl orange from 100-400 ppm was also studied in the context of large solution volume. The results suggested that apparent pseudo-first-order homogeneous reaction model can be used for describing the kinetic behaviour and higher photocatalytic activities induced through large solution volumes; kapp is 5.34 × 10-2 min-1 for 250 ppm catalyst at 800 mL methyl orange solution. In addition, the photocatalytic activity of WO₃ nanorods was 3.6 times higher than that of commercial P25 TiO₂ powder.