Sonophotocatalytic treatment of rhodamine B using visible-light-driven CeO 2 /Ag 2 CrO 4 composite in a batch mode based on ribbon-like CeO 2 nanofibers via electrospinning.

CeO2 /Ag2 CrO4 composite photocatalyst was successfully fabricated using electrospinning and calcination and chemical precipitation method based on CeO2 ribbon-like fibers and characterized by field-emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS) and Fourier-transform infrared spectroscopy (FT-IR). The as-obtained CeO2 /Ag2 CrO4 composite used photocatalytic performance in the sonophotodegradation of rhodamine B in aqueous solution under visible-light (LED) irradiation. DRS analysis illustrates that CeO2 /Ag2 CrO4 composite exhibited enhanced absorption in the visible region-attributed CeO2 nanofibers. The effect of four effective parameters including initial concentration of rhodamine B (RhB), photocatalyst dosage, pH, and irradiation time was studied and optimized using central composite design. The kinetic studies confirmed ability of pseudo first-order reaction based on the Langmuir-Hinshelwood model for fitting empirical data, while its rate constant (kobs ), L-H rate constants (kr ), and L-H adsorption constants (KA ) were 0.0449 min-1 , 11.66 mg L-1  min-1 and 1.09E-3 mg L-1 , respectively. The enhanced photocatalytic activity could be ascribed to the ultrasound field and formation of a heterojunction system among CeO2 and Ag2 CrO4 , which lead to a better mass transfer and higher efficiency of charge electron-hole separation, respectively.