Preparation And Photocatalytic Performance Of Carbon Nitride/carbon Nanofiber Composite Membran

Photocatalytic technology has outstanding advantages such as low toxicity,high efficiency,mild reaction,and is widely used in the removal and treatment of organic dyes in textile printing and dyeing wastewater.However,the powdered photocatalyst is difficult to recycle and easily causes secondary pollution,which is greatly restricted in practical applications.To solve the above problems,our study used polyacrylonitrile（PAN）-based nanofiber membrane as a carrier to construct a graphite carbon nitride（g-C₃N₄）photocatalytic material with a heterogeneous structure,and prepared nanofibers with photocatalytic properties.The photocatalytic performance of the nanofiber composite film to degrade Rhodamine B（Rh B）and other organic dyes was studied.The main research contents are as follows:First,g-C₃N₄@PAN/PEO nanofiber membranes were prepared by loading g-C₃N₄on PAN/PEO（polyacrylonitrile/polyethylene oxide）nanofiber membranes based on the blending electrospinning technology.The influence of g-C₃N₄ addition amount on the photocatalytic performance of g-C₃N₄@PAN/PEO nanofiber membrane was emphatically discussed.When the amount of g-C₃N₄ added was 12%,g-C₃N₄@PAN/PEO nanofiber membrane can degrade 93%of Rh B under visible light irradiation.Moreover,the g-C₃N₄@PAN/PEO nanofiber membrane had good reusability,and maintained 80%of the original activity after repeated 5 times.To improve the photocatalytic performance of the nanofiber membrane,a combination of high-temperature calcination and vapor deposition was used to load g-C₃N₄ onto carbon fibers prepared a C-C₃N₄ nanofiber membrane.The prepared carbon fiber had excellent visible light absorption performance and the adsorption capacity.The best adsorption degradation rate of C-C₃N₄ nanofiber membrane for Rh B increased from 93%to 98%,which is mainly due to the synergistic effect of adsorption and photocatalysis.In addition,after 4 cycles of experiments,the photocatalytic activity of C-C₃N₄ nanofiber membranes also remained above 70%,which proved that C-C₃N₄composite nanofiber membranes and nanofibers had good reusability.In order to further improve the photocatalytic performance,Ti₃C₂ nanosheets were introduced to construct TM-CN（Ti3C2/g-C3N4）powder with a heterogeneous structure.The C-TM-CN nanofiber composite membrane was constructed by combining TM-CN and carbon nanofiber membrane.Among them,TM-CN powder reduced the separation and recombination efficiency of photogenerated electron-hole pairs.Therefore,the photocatalytic degradation performance of Rh B was further improved.Finally,the C-TM-CN nanofiber composite film had the best photocatalytic degradation rate of Rh B as high as 99%,and it had good reusability.After the composite membrane was repeated 5 times,the photocatalytic degradation ability of Rh B still remained above 95%.In summary,the composite nanofiber membrane was prepared based on the advantages of photocatalytic nanomaterials had excellent photocatalytic performance and reusability,and could effectively degrade organic dyes in printing and dyeing wastewater.And,this study provides new research ideas for the preparation of high-performance catalytic composite materials,and further broadens the practical application of catalytic materials.