About this website 50 mL of 20 mg/L MB solution was then added to the tubes. The mixed solutions were placed in the photocatalytic reactor, stirred in the dark for 60 min, and then exposed to UV light irradiation. UV–vis spectroscopy was
used to detect the solution absorption. Results and discussion Thermoanalysis of composite fibers TG-DSC was performed on the PVP-Ti composite fibers mat. The curve in Figure 1 shows three weight loss stages corresponding to 240°C, 374°C, and 479°C are present. The first weight loss stage occurred below 240°C, and an endothermic band related to the DSC curve was obtained buy Pevonedistat because of desorption of water and decomposition of crystal water. The rate of weight loss between 240°C and 374°C was faster than at any other temperature, and an TGF-beta inhibitor clinical trial exothermic peak attributed to the decomposition of organic components was observed. Above 479°C, no significant weight loss was observed, which indicates that the organic portion of the PVP/butyl titanate composite fibers had been
completely removed. According to the DSC results from 374°C to 479°C, the curve exhibited two endothermic peaks: one from anatase structure formation and the other from phase transformation. Figure 1 the TGA/DSC diagram for the composite fibers. Phase analysis of calcined fibers Figure 2 shows the XRD patterns of composite fibers calcined at different temperatures (500°C, 550°C, 600°C, and 650°C). After preservation in N2 at 500°C, a pure anatase phase was produced. The peaks of rutile phase of TiO2 appeared with increasing temperature. Only check details the pure rutile phase remained when the temperature increased to 650°C. After preservation in NH3 for 4 h, the samples showed a similar change process; the anatase phase with a small amount of the rutile phase appeared at 550°C.
The extent of crystal transformation (from anatase phase to rutile phase) of samples under preservation heating in NH3 was lower than that of samples under preservation heating in N2. At 650°C, a small amount of anatase phase remained. A smaller degree of crystal transition was observed at this temperature because ammonia has high activity in the atmospheres, and the nitriding extent of fibers is higher than fibers in N2, so N atoms get into substitution position. The diffraction peak at 2θ = 20.9°, which corresponds to the crystalline phase of PVP, cannot be observed in the figure. These findings are consistent with the TG results, which indicate no obvious losses in the mass above 500°C . According to the XRD patterns obtained, no obvious doping-related peaks appeared despite the doped samples showing characteristic TiO2 peaks, which may be due to the lower concentration of the doped species under nitrogen atmosphere.