Insight into the synergistic effect of adsorption and photocatalysis for the removal of organic dye pollutants by novel BiFeO3@GO fibers

BiFeO 3 @GO nanocomposite fibers were successfully synthesized by the electrospinning and simple ultrasound method. The structure, morphology, optical, composition and magnetic properties of BiFeO 3 @GO samples were characterized by XRD, FT-IR, SEM, TEM, UV–Vis and XPS analyses. The results showed that the removal of organic dye pollutants was enhanced by novel BiFeO 3 @GO fibers through the adsorption–photocatalytic synergy. The removal rates of methylene blue (MB), Congo red (CR), Rhodamine B (RHB) and norfloxacin (NOR) dyes were increased by 64.5%, 33.6%, 43% and 61.1%, respectively. Then it was a benefit to remove MB when the pH is between 6.0 and 10.0, while it was favorable for adsorption in a neutral environment and photocatalysis in an acidic or alkaline environment. The adsorption process of MB dyes was more in line with the pseudo-second-order kinetic model for BiFeO 3 @GO nanocomposite sample with 3 mg graphene oxide weight (GO 3 ). The adsorption data were well fitted by Langmuir adsorption isotherm, which indicated that the adsorption process was a monolayer adsorption. The adsorption of MB dyes on GO 3 nanocomposite fibers appeared to be a favorable process (0 <  R L  < 1). Moreover, the trapping experiments showed that · OH was the main active substance during photocatalysis, and the FT-IR tests indicated that nanocomposite fibers can degrade MB into CO 2 and H 2 O under the synergistic effect of adsorption and catalysis.