Preparation Of TiO₂-based Micro-nano Fiber Membranes By Electrostatic Spinning And Study Of Catalytic Properties

With the rapid development of China’s economy,the problem of water pollution has become increasingly serious,causing adverse effects on China’s environment.Researchers have been working on various types of water pollution treatment methods.As a semiconductor catalyst,Ti O₂ has a wide range of applications in the field of photocatalysis.However,Ti O₂ can only be photocatalyzed under ultraviolet light,which limits the scope of its photocatalytic application,and the doping modification of Ti O₂ carbon allows Ti O₂ to be photocatalyzed under visible light.Different crystal forms of Ti O₂ also affect its photocatalytic efficiency.In this paper,cellulose acetate（CA）was used as the carbon source and tetrabutyl titanate was used as the titanium source to make a spinning solution,and the micro-nanofiber was spun by electrospinning technology and calcined to obtain a carbon-doped titanium dioxide fiber film,so that Ti O₂ was correspondingly under visible light,and titanium dioxide with anatase phase and rutile phase mixing effect was prepared by controlling the calcination temperature,which enhanced its photocatalytic degradation ability,which is different from the traditional Ti O₂ catalyst,its shape is film-like,which is conducive to recycling and reuse.The microscopic morphology of the fiber membrane was displayed by scanning electron microscopy（SEM）,the crystal form formed by X-ray diffraction（XRD）,the formation of bonds in the fiber membrane by X-ray photoelectron spectroscopy（XPS）,the characteristic functional groups in the fiber membrane by infrared spectroscopy,and the residual carbon amount by thermogravimetric analysis（TGA）.The photocatalytic degradation performance test was carried out under visible light,and the results showed that carbon-doped titanium dioxide fiber membrane had good photocatalytic degradation of methylene blue dye under visible light,and the degradation rate could reach99.7%within 50 minutes when the mass fraction of Ti O₂ was 18%and the calcination temperature was 750°C.At the same time,the optimal degradation conditions under different conditions of p H,catalyst addition and pollutant concentration were explored,and the alkaline conditions of p H=12,catalyst addition of 0.5 g and MB concentration of 25 mg/L had the best decomposition effects.The quenching experiment confirmed that h⁺and·O₂^-radicals play the main role in the degradation of methylene blue（MB）.Due to the strong hydrophobicity of carbon-doped titanium dioxide fiber membrane,the degradation rate can still reach 81%after five recycles of 120 min,which has good recycling properties.In the experiment of activated persulfate catalytic degradation,it was concluded that 20mmol/L sodium persulfate was added to 100 mg/L methylene blue solution,p H=10,and when the catalyst dosage was 0.2g/L,the MB degradation rate reached 100%at 70min.At the same time,the effects of·OH and·O^2-radicals were studied by quenching experiments in the process of carbon-doped titanium dioxide activated persulfate to degrade MB,and the effects of four inorganic anions(Cl^-,CO₃^2-,SO₄^2-,NO₃^-)on the degradation of methylene blue by carbon-doped titanium dioxide fiber membranes were investigated.CO₃^2-in the water environment has the greatest influence on the degradation efficiency of MB.