Glass fiber supported BiOI thin-film fixed-bed photocatalytic reactor for water decontamination under solar light irradiation.

BiOI powder has been proved to be an efficient photocatalyst, but the difficulty in removing it from water after reaction limits its application in real water treatment. To solve this problem, a thin-film fixed-bed reactor (TFFBR) was set-up by developing a BiOI thin film on glass fiber cloth (GFC). The composition and structure of the as-prepared films were characterized with X-ray diffraction, X-ray photoelectron spectroscopy, field emission microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The BiOI thin film was made by painting a silica sol containing BiOI on GFC, which could be tailored to desired sizes to accommodate the TFFBR. The mass of BiOI on the GFC increased with the number of iterations of the painting process. SiO2 sol glued the BiOI particles tightly onto the GFC, making the thin film strong enough to resist fluid flushing in the TFFBR. The photocatalytic activity of the BiOI thin film was investigated by degrading bisphenol A (BPA) under simulated sunlight. Ninety eight percent of BPA (20 mg/L in 2 L) was degraded by the BiOI thin film sample of seven layers (GFC-7) on the TFFBR within 8 hr irradiation. The GFC-7 displayed good photocatalytic ability toward artificial sewage containing BPA in a wide pH range (5-9), and also demonstrated excellent durability and reusability. The working conditions were optimized and it was found that the thickness of the fluid film and residence time over the thin film were key factors affecting the photocatalytic efficiency.