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Σάββατο 26 Ιανουαρίου 2019

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

Abstract

CeO2/Ag2CrO4 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/Ag2CrO4 composite used photocatalytic performance in the sonophotodegradation of rhodamine B in aqueous solution under visible-light (LED) irradiation. DRS analysis illustrates that CeO2/Ag2CrO4 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 Ag2CrO4, which lead to a better mass transfer and higher efficiency of charge electron–hole separation, respectively.



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