Fabrication and photocatalytic degradation of reactive blue 19 by CuWO4, Ag3PO4, and CuWO4-Ag3PO4 composites under visible light irradiation

CuWO4 nano-powder was synthesized via a hydrothermal reaction using CuCl2.2H2O and Na2WO4.2H2O in the stoichiometric 1:1 Cu:W molar ratio and sodium citrate as raw materials. In addition, Ag3PO4 was synthesized by a precipitation method using Na2HPO4 and AgNO3. Finally, CuWO4-Ag3PO4 nanocomposite was synthesized in a precipitation route using the as-synthesized CuWO4 and Ag3PO4 as raw materials. The synthesized materials were characterized by powder X-ray diffraction (PXRD) technique. To investigate the effect of concentration of the basic solutions on the morphology of the obtained materials, the morphologies of the synthesized materials was studied by field emission scanning electron microscopy (FESEM) technique. As shown by the FESEM images, the morphology of CuWO4 material was spherical particles. Besides, the photocatalytic performance of the as-synthesized nanocomposites was studied for the degradation of Reactive Blue 19 (RB19) under direct visible light irradiation. For the purpose, several reaction parameters affect the degradation yield, such as catalyst amount, pH value and absence/presence of light were investigated. The data showed that the photocatalytic yield at the presence of light irradiation was more when the pH value of the solution was in the acidic range, the weight percent of silver phosphate in the composite mixture was more, and the catalyst amount was more. The findings revealed that a 0.05 g nanocomposite containing 0.24 mmole of Ag3PO4, with an initial pH of 3 and RB 19 volume and concentration of 100 mL and 30 mg/L, respectively, could achieve approximately complete removal after 30 min under visible light illumination.