Waste cotton fiber/Bi2WO6 composite film for dye removal

In this study, the waste cotton fiber (WCF)/Bi2WO6 (BWO) composite film was prepared from BWO and WCF, which is dissolved in ionic liquid ([Amim]Cl). The samples were systematically characterized by scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area and UV-Vis diffuse reflection spectroscopy. The removal efficiency of rhodamine b (RhB) and methylene blue (MB) by the composite film in the dark and under visible light were investigated. The results show that the removal abilities of the composite films for RhB and MB are improved with the rise of BWO content. The removal efficiency of RhB and MB arrives at 93.73% and 97.04% under visible light irradiation when the BWO content is 1.5%, respectively. The degradation rate of MB still reaches 89% after four cycle tests. Superoxide radicals (O-center dot(-2)) and holes (h(+)) plays a major role in the degradation and hydroxyl radicals ((OH)-O-center dot) plays an minor role. The WCF/BWO composite film can be potentially applied in photocatalysis and wastewater treatment fields.