The Study Of Preparation And Photocatalytic Activity Of TiO₂ By Electrospinning

Water is one of the substances for the human survival.And now, the shortage of water resource in the worldwide not only restricts the economic development, but also threatens the survival of mankind. More and more people are devoted to developing technology for waste water treatment. The photocatalytic degradation is one of the new developed techniques. Photocatalytic oxidation technology is usually adopted for its high effciency, low energy consumption, simple operation, mild reaction condition, wide application range, and little secondary pollution.Nano-TiO2 is widely applied in photocatalysis degradation due to its advantages of large specific surface area, non-toxicity, low cost, and long service life. The usage of nano-TiO2 is limited by its strong polar, high surface free energy and easily agglomeration in water and organic solvents, which reduces the effective action area of nano-TiO2. Meanwhile, the coverage rate of organic pollutant on nano-TiO2 surface is very low. And the nano-TiO2 photocatalyst only absorbs the very small ultraviolet part of solar light due to its wide band gap of 3.2eV. All of the above factors results in the low adsorption and photocatalytic degradation efficience of the organic pollutant. Therefore, nano-TiO2 should be modified to solve above problems.The Ti(OC4H9)4/Zn(CH3COO)·2H2O PVP fibers were prepared by electrospinning using polyvinyl pyrrolidone(PVP)/Zn(CH3COO)2·4H2O/Ti(OC4H9)4 sol, and then Ti(OC4H9)4/Zn(CH3COO)2·2H2O PVP fibers were heated at 550℃for 6h to obtain Zn2+ doped TiO2 nanofibers. The structure and properties of the ZnO-TiO2 coaxial fibers were investigated using FTIR,XRD, SEM. The photocatalytic properties of ZnO-TiO2 nanofibers were studied by the degradation of methylene blue under UV irradiation.The photocatalytic degradation of 100mL 2.0mg/L methylene blue by ZnO-TiO2 nanofibers under UV irradiation for 40 minutes showed that ZnO-TiO2 exhibited high photocatalytic activity. The degradation rate of methylene blue was more than 70%.The Ti(OC4H9)4/Ni(CH3COO)2-4H2O PVP fibers were prepared by coaxial electrospinning using PVP/Ni(CH3COO)2·4H2O sol as the core and PVP/Ti(OC4H9)4 sol as the shell, and then Ti(OC4H9)4/Ni(CH3COO)2·4H2O PVP fibers were heated at 550℃for 6h to obtain NiO-TiO2 coaxial nanofibers. The structure and properties of the NiO-TiO2 coaxial fibers were investigated using FTIR, XRD, SEM, and TG. The photocatalytic properties of NiO-TiO2 coaxial nanofibers were studied by the degradation of methylene blue under UV irradiation. In comparing with TiO2 nanofibers, the NiO-TiO2 coaxial nanofibers exhibited higher photocatalytic activity for the degradation of methylene blue. And the catalyst could be used repeatedly.The fabrication of the kryptol nanofibers were investigated, which were made of polyvinylpyrrolidone (PVP) sol using the electrospinning technique. And then they were preoxidized at 250℃and carbonized at 850℃. The carbon nanofibers were soaked by titanium n-butyloxide (Ti(OC4H9)4), then heat-treated at 200℃and calcined at 550℃to obtaine TiO2 nanoparticles loaded on the carbon nanofibers. The morphological structure of the ultrafine fibers were studied by SEM, FT-IR, and XRD. TiO2 loaded on carbon nanofibers degraded 100mL 2.0mg/L methylene blue under UV irradiation for 40 minutes, which indicated that TiO2 loaded on carbon nanofibers exhibited high photo-catalytic activity. The degradation rate of methylene blue was more than 75%. And the TiO2 nanoparticles loaded on the carbon nanofibers were good for reused.