| Dye wastewater pollution is increasingly serious, and photocatalytic oxidation technology has many advantages in terms of dyes decolorizing. However, because of the granular shape of the ordinary light catalysts and their bigger forbidden band width, it causes difficulty in separation from dye solution after reaction and leads to secondary pollution as well as the problem of limited utilization of visible light. Flexible alumina ultra-fine fiber has the large specific surface area, high chemical stability and high strength, therefore it is suitable for being used as a carrier or support body of the photocatalyst. Compared with the general method of fabricating the inorganic oxide fiber with a higher viscosity sol, electro-blown spinning technology has many advantages such as continuous process, high fiber yield and excellent fiber performance.Flexible Al2O3 ultra-fine fiber was prepared with three steps, which were sol-gel technique, electro-blown spinning and calcination process. The effects of the sol-gel concentration and the parameters during electro-blown spinning on the morphology and the fiber diameter distribution were discussed and optimized by response surface method. The systematic research on calcination process was carried out to optimize the calcination conditions. The comparison between solution blown spinning and electro-blown spinning were performed through fiber morphology and other properties. And the universality of the electro-blown spinning was verified. The results of response surface method demonstrated that the single variable influenced CV values of as-spun fiber diameter was successively decreased by air-flow pressure (C), sol viscosity (A), sol feeding rate (D) and applied voltage (B). The optimized process parameters were sol viscosity 1.57Pas, applied voltage 40.25kV, air-flow pressure 0.15Mpa, and sol feeding rate 29.37ml/h. The predicted CV value (10.90%) was close to the actual one (11.37%) obtained under optimized process parameters. The morphology and crystal property of the resulted alumina fiber were influenced by heating rate and calcined temperature significantly. The fiber surface was smooth and no defects with low heating rate, defects appeared as heating rate further increased. The fiber diameter was decreased with the calcined temperature elevated, and the resluted fiber crystal type was determined by the the calcined temperature. Excellent η-Al2O3 fiber was fabricated after calcined at 1100℃ with 1℃/min heating rate. Compared with solution blowing method, the electro-blown spinning fiber had better morphology, more uniform diameter distribution and mat pore size due to the coupling effects of the electric force and air flow force. With the optimized parameters, the average fiber diameter was 2.75μm and more uniform. Moreover, electro-blown spinning method performed high universalizable, especially for the high concentration sol-gels, such as ZrO2, CeO2 and so on.Loaded Fe2O3/Al2O3 catalyst was obtained via immersing Al2O3 ultra-fine fiber into iron oxide gel, subsequently calcining at high temperature. The degradation of Acid Red in the present of H2O2 and UV-light catalyzed by the obtained catalyst was studied. The results showed that the Fe2O3 sol particles were successfully loaded on the Al2O3 ultra-fine fiber surface. The pore size, impregnation concentration and time had effects on the iron content. High content iron catalyst could be obtained with large pore size, high impregnation concentration and long immersion time. The better catalysis efficiency can be obtained when the iron loaded content was 195.5mg/g, calcined under 500℃. The elevation of initial dye concentration decreased the degradation percentage and the higher decoloration percentage was achieved at pH=6. Additionally, the loaded catalyst possessed good recycling stability. Under the optimized conditions, the decoloration percentage was 95% within 120 min for the first run. And it can be maintained 70% after three rounds.Finally, combined with the coupled photocatalytic effects between CeO2 and CuO, as well as the outstanding fiber forming properties of Al2O3 sol, the CuO-CeO2-Al2O3 composite ultra-fine fiber photocatalyst was successfully prepared via electro-blown spinning and calcination method under different conditions. The effects of various parameters and conditions on the morphology and diameter of the as-spun fibers were investigated, and the process parameters were optimized. The as-spun fibers were treated at high temperature and then different composite catalysts were prepared. The impacts of calcination temperature and copper content on the catalytic effect were studied. At last, the cycle stability and catalytic degradation mechanism of catalyst were analyzed. The results showed that the morphology and diameter distribution of the as-spun composite fibers were significantly affected by the processing parameters and the as-spun fibers formed with alumina sol content 2g, air flow pressure 0.15MPa, applied voltage 40kV, feeding rate 30mL/h and PVP content 4g possessed better morphology and more uniform diameter distribution with average diameter of 3.0μm. The visible light catalytic effect of CuO-CeO2-Al2O3 catalyst was obviously improved by doping of copper element. When the calcination temperature was 400℃ and the molar ratio between Ce and Cu was 1.96, the catalyst showed better catalytic effect. Under the visible light, the dye degradation rate was about 75% with the initial concentration of 80mg/L and reaction time of 180min while the catalyst had good cycle stability, and the dye decolorization rate could be maintained about 50% reaction after three rounds. The addition of alumina sol can effectively improve the flexibility of the composite catalyst, and can play an important role in support of the catalyst to maintain good fiber morphology. The catalysts were readily separated from the dye solution, avoiding secondary contamination.
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