Photocatalytic degradation of azo dye acid red G by KNb3O8 and the role of potassium in the photocatalysis

Abstract The layered photocatalyst KNb 3 O 8 was prepared using a solid-state reaction method. Scanning electron microscope (SEM) and X-ray diffractometer (XRD) were used to characterize the photocatalyst. The photocatalytic degradation of acid red G over the photocatalyst under UV irradiation was studied. The influences of catalyst dosage, initial concentration of acid red G were determined as well. The kinetics of photocatalytic degradation of acid red G follows first-order kinetics. The H + -exchanged KNb 3 O 8 was prepared and its photocatalytic activity is much lower than that of the KNb 3 O 8 . The roles of the layered structure of the KNb 3 O 8 and the potassium ions between the layers in the photocatalytic reaction were discussed.