Study On Preparation And Photocatalytic Of Titanium Dioxide Loaded Nanofiber Aggregate

Titanium dioxide?TiO₂?is widely used in sewage treatment,sterilization and disinfection,anti-fog and self-cleaning and other fields due to its green,cheap price and excellent photocatalytic activity.However,the TiO₂ nanocrystalline powder is prone to agglomeration during use.At the same time,due to the small size of the nanoparticles,it cannot be recycled after use,and it is easy to cause secondary pollution.Electrospinning is the unique method that can prepare nanofibers continuously,the nanofibers produced by it have high aspect ratio and large specific surface area.On the one hand,it can solve the problem of easy agglomeration of TiO₂ nanocrystalline powders,on the other hand,it can provide more active sites for TiO₂ photocatalytic reaction,which makes it very versatile.Firstly,the sol-gel method was used to successfully prepare mixed-crystal TiO₂ nanocrystalline powders with different anatase/rutile ratios by adjusting the calcination temperature?550-750°C?.The SEM results showed that the micro-morphology of the nanocrystalline powder was spherical.As the calcination temperature increases,the anatase gradually changes to rutile.The TiO₂nanocrystalline powders prepared at 550°C are pure anatase,the TiO₂ prepared at 750°C are pure rutile,and the TiO₂ prepared at 600,650,675 and 700°C are all mixed-crystal structure.At the same time,as the temperature increases,the particle size of the nanoparticles increases.The photocatalytic activity of TiO₂ nanocrystalline powders with different mixed crystal ratios was studied using 12%PAN as a carrier and photocatalytic degradation of rhodamine B as a model.The results show that the 1%TiO₂?650°C?/PAN sub-micron fiber membrane exhibits the best photocatalytic activity.Under the irradiation of 500W UV lamp,100mg of this sample,the degradation rate of 100ml 5mg/L rhodamine B solution was 95.6%after 210min,the ratio of anatase to rutile is 75%:25%at this temperature.Secondly,the average diameter of the sub-micron fiber decreases from 241.5nm to 153.3nm as the mass fraction of TiO₂ increases.According to the photocatalytic activity test of TiO₂/PAN sub-micron fiber membrane with different mass fractions,when the mass fraction of TiO₂ is 3%,the degradation rate of rhodamine B is as high as 99.9%after 150 minutes of ultraviolet light irradiation,showing good photocatalytic performance.Besides,when the mass fraction was 3%,the antibacterial rate of sub-micron fiber membrane against E.coli and S.aureus after 18 hours of cultivation under 3000±5 Lux fluorescent lamps was 93.17%and 92.85%,respectively.Using rhodamine B solution and methylene blue solution to visually evaluate the self-cleaning performance of the TiO₂/PAN sub-micron fiber membrane with a mass fraction of 3%,it was found that with the extension of the light time,the color of rhodamine B solution and methylene blue solution gradually faded and finally faded.Finally,the sub-micron fiber/cotton blended yarn and core-spun yarn were successfully prepared using electrospinning.The results show that the strength and elongation of the blended yarn are almost unchanged compared to the pure cotton yarn,while the strength and elongation of the core-spun yarn are significantly higher.In addition,the antibacterial test results showed that the antibacterial rate against E.coli and Staphylococcus aureus of core-spun yarns covered with one-time is 62.70%and 56.80%,respectively,while the blended yarns had only 15.08%and 14.50 of two bacteria.In order to further improve the antibacterial performance of the core-spun yarn,the thickness of the sub-micron fiber/cotton core-spun yarn is increased by controlling the number of coatings.As a result,as the thickness increases,the strength and elongation of the core-spun yarn become larger.The average strength increased from 250.0cN of pure cotton yarn to 411.6cN covered10 times,and the average elongation increased from 13.9%to 16.6%.The antibacterial test results found that when covered 10 times,the sub-micron fiber/cotton core-spun yarn had 87.97%and85.80%antibacterial activity against E.coli and Staphylococcus aureus.Finally,the photocatalytic activity test showed that 100mg of this composite yarn degraded 100 ml of 5 mg/L rhodamine B solution for 150 min,and the degradation rate was 85.7%.This result indicates that the sub-micron fiber/cotton core-spun yarn has a better self-cleaning effect.