Statistically optimized synthesis of cadmium tungstate nanoplates for use as a photocatalyst

An orthogonal array design (OAD) was used for optimizing the controlled and facile precipitation of cadmium tungstate nano-plates as flower-like clusters. The reaction was performed by adding cadmium ion solutions to those of tungstate. The OAD was used to optimize the influence of the concentrations of cadmium and tungstate solutions, the rate of adding the cation solution to that of the anion and the reactor temperature on the properties of the product. These effects quantitatively were evaluated through the analysis of variance (ANOVA), while it was revealed that concentration of the cation solution, flow rate and reactor temperature have considerable effects on the qualities of the product and their optimal values were hence determined. ANOVA exhibited that under the favorable experimental condition, the thickness of cadmium tungstate nanoplates will be about 21 ± 2.9 nm. The morphology and composition of the optimal product were assessed using X-ray diffraction, scanning electron microscopy, FT-IR spectroscopy, and diffuse reflectance/transmittance spectroscopy. This product was also evaluated as a photocatalyst for the photo-induced removal of methylene blue and metyl orange and the results revealed that CdWO₄ can be decolorize 90 and 86% of MB and MO after 100 and 50 min, respectively.