The Preparation And Photocatalytic Properties Of The Cotton Cellulose Nanofibers/ZnO-based Composites

With the development of industry,wastewater pollution has become a thorny issue that seriously threatens human survival.At present,there are many methods to solve the problem of wastewater pollution,in which photocatalytic degradation of pollutants has attracted extensive attention as a non-toxic,environmentally friendly,green technology that can directly utilize light energy.Among many photocatalytic materials,ZnO,as an oxide semiconductor with excellent physical and chemical properties,has important applications in photocatalysis.However,due to its wide band gap,its utilization of light energy has certain limitations,so extending the optical response range of ZnO is a very meaningful work.In addition,monomer ZnO has a high photo-generated carrier recombination rate,so how to reduce its photo-generated carrier recombination rate is also an effective means to improve photocatalytic performance.On the other hand,how to improve the dispersibility of the catalyst is also an important factor to improve the catalytic performance.As a natural polymer material,cotton fiber has the characteristics of non-toxic and non-polluting,and the surface is easily biodegraded.The molecular structure of polyhydroxyl and micro-structure with large specific surface area makes nano-cotton fiber a good base material.1.Preparation and photocatalytic properties of cotton cellulose nanofibers/ZnO/Ag₂S NanocompositesThe cotton cellulose is pulverized and dissolved to prepare a spinning precursor solution,and the spinning precursor liquid is prepared into nano cotton fibers by electrospinning,and the zinc oxide nanorods are loaded on the fibers by hydrothermal method.Ag₂S was deposited on the surface of ZnO nanorods by cyclic ion adsorption method.The prepared samples were characterized by SEM,TEM,XRD,XPS and PL.The results show that Ag₂S is successfully combined with nano-cotton fiber/ZnO.The efficiency of photocatalytic degradation of MB after Ag₂S modification is 3.4 times that of without Ag₂S.It is proved that the photocatalytic performance is obviously improved,which can be attributed to the high photo-generated carrier separation efficiency of ZnO/Ag₂S heterojunction and the excellent visible light response of Ag₂S.After four cycles of recycling,the degradation rate was only 10%reduced,indicating that the composite structure has good cycle stability.2.Preparation and photocatalytic properties of cotton cellulose nanofibers/ZnO/AgCl NanocompositesNano-cotton fiber/ZnO/AgCl was prepared by the method of cyclic ion adsorption with different concentration ratios of AgNO₃/NaCl.The prepared samples were characterized by SEM,TEM,XRD,XPS and PL.The results show that AgCl particles are successfully combined with ZnO,and further explored by photocatalytic degradation experiments.The degradation efficiency of nano-cotton fiber/ZnO/AgCl to rhodamine B is 5.4 times that of without AgCl-modified samples.The photocatalytic efficiency has been significantly improved,which can be attributed to the improvement of the utilization of light energy by AgCl and the high photo-generated carrier separation efficiency of the unique Z-type ZnO/AgCl heterojunction.In addition,nano-cotton fiber/ZnO/AgCl also exhibits high cycle stability.3.Preparation and photocatalytic properties of cotton cellulose nanofibers/ZnO/AgBr nanocompositesNano-cotton fiber/ZnO/AgBr was prepared by the method of cyclic ion adsorption with different concentration ratios of AgNO₃/NaBr.The prepared samples were characterized by SEM,TEM,XRD,XPS and PL.The results show that AgBr particles are successfully combined with ZnO,and further explored by photocatalytic degradation experiments.The degradation efficiency of nano-cotton fiber/ZnO/AgBr to rhodamine B is 5.4 times that of without AgBr-modified samples.The photocatalytic efficiency has been significantly improved,which can be attributed to the improvement of the enhanced visible light response by AgBr and the high photo-generated carrier separation efficiency of the unique Z-type ZnO/AgBr heterojunction.In addition,nano-cotton fiber/ZnO/AgBr also exhibits high cycle stability.