Preparation And Properties Of Polytetrafluoroethylene Ultrafine Fiber Supported Titanium Dioxide Photocatalyst

The traditional method of dyeing wastewater treatment is at low cost and with simply operation, but it also has some shortcomings such as long processing cycle, removing incomplete, easy to cause the secondary pollution and so on. The photocatalytic degradation method can avoid the shortcomings above. Polytetrafluoroethylene (PTFE) is a polymer with high strength, high acid and alkali resistance performance, high temperature resistance performance and other excellent performances, it is suitable for catalyst support. This paper mainly researched the preparation PTFE/PVA/boric acid nanofiber membrane by electrospinning, and then by sintering to prepare PTFE nanofiber membrane and loading TiO2 as the catalyst to degradation methylene blue solution.Firstly, the influencing factors of electrospinning PTFE nanofiber morphology was explored using single factor variable method and through SEM images and diameter distribution we got the best process parameter for the electrospinning. It was that the mass of PTFE and PVA ratio was 15:1, additive boric acid amount was 15 μL, mixing time was 14 h, voltage was 30 kV, receiving rate was 200 r/min, and receiving distance was 15 cm.Secondly, the PTFE/PVA/boric acid nanofiber membrane was permeated into the mixed solution of the tetrabutyl titanate, anhydrous acetic acid and anhydrous ethanol, then after sintering, the TiO2/PTFE photocatalyst was successfully prepared. The existence of TiO2 and PTFE were determined by the testing instruments of SEM, EDS, FT-IR, XPS and XRD.Finally, TiO2/PTFE nanofiber membrane was used to photocatalytic oxidation degradate the methylene blue solution. It was discussed the influences to degradation reaction, the result showed, In light condition the degradation efficiency was greater than the dark state; when irradiation distance was 30 cm, the light intensity was optimum and the degradation efficiency was the highest; Compared with methyl orange and acid red, the degradation efficiency of methylene blue was highest; Degradation efficiency was inversely proportional to the dye concentration; Fiber diameter in 600-700 nm, diameter distribution range was narrow, the degradation efficiency was higher; Under the violet light (300 W,365 nm) irradiation, when dipping time was 7 h, calcination temperature was 450℃, holding time was 15 min, the degradation efficiency was the best. In addition, the effect of the number of cycles on the degradation efficiency was also studied. It was shown the degradation efficiency of methylene blue was still 46% after recycling for 5 times, indicating that the photocatalyst can be reused. It provides a new solution to slove the problem that the pure TiO2 photocatalyst is easy to gather and cause the secondary pollution.