Preparation And Properties Of ZnO@Cu-BTC/PLA Fiber Membranes

With the rapid development of the printing and dyeing industry,the problem of wastewater caused by the large-scale use of organic dyes needs to be solved urgently.As a copper-based metal organic framework material,Cu-BTC has an octahedral structure and a unique "pocket-channel" structure.Because of its ultra-high specific surface area,pore volume and pore size,it is widely used in gas storage,adsorption and other fields.In this paper,influences of different reaction conditions on the structure and surface morphology of Cu-BTC were studied.ZnO nanoparticles were used to improve the adsorption performance of Cu-BTC to Congo red(CR).At the same time,ZnO@Cu-BTC/PLA nanofibrous membrane were prepared by electrospinning technology.The fibrous membrane improves the recycling performance of the adsorbent.In this paper,the Cu-BTC particles were prepared by the hydrothermal synthesis,the mass ratio of reactants,reaction temperature and reaction time were adjusted,and the optimal process parameters for preparing Cu-BTC were determined through SEM,XRD,TGA,BET and adsorption experiments.The optimal conditions were Cu(NO3)2·3H2O:H3BTC=2:1,reaction temperature 120℃,reaction time 12 h.The results show that the Cu-BTC prepared under this condition has the best morphology,uniform size,and minimal impurities.At the same time,the sample had a specific surface area of 1197.5 m2/g,a pore volume of 0.63 cm3/g,and a pore diameter of 2.9 nm.The maximum adsorption capacity for Congo red dye was 745.7 mg·g-1,and the recycling rate of the adsorbent was 60.1%.The ZnO nanoparticles doped into the reaction system,and the electronegativity of ZnO was used to form a linkage effect with Cu2+active sites to improve the adsorption performance of Cu-BTC to anionic dyes.Through the SEM,XRD,TGA,BET and adsorption experiments,it was found that the optimal doping amount of ZnO nanoparticles was 10wt%.Compared with Cu-BTC,the particle size of ZnO@Cu-BTC becomes smaller,and the specific surface area,pore volume and pore diameter increased to 1653.0 m2/g,0.83 cm3/g,and 3.4 nm,respectively.The adsorption capacity of CR increased to 945.5 mg·g-1.After three cycles,the recycling rate of the adsorbent was 68.8%.The ZnO@Cu-BTC/PLA nanofiber membrane was prepared by electrospinning technology.After SEM and mechanical properties tests,it was determined that the optimal PLA concentration and ZnO@Cu-BTC content were 8wt%and 5wt%,respectively.The pure PLA nanofiber prepared by 8wt%PLA had the advantages of porous structure,uniform fiber thickness,good toughness and high strength of the fiber membrane.On the basis of 8wt%PLA,5wt%ZnO@Cu-BTC particles were added to prepare the spinning solution.The ZnO@Cu-BTC/PLA nanofiber membrane prepared by the electrospinning method still had good mechanical properties,and the fiber membrane was made from the original The super-hydrophobic material was transformed into a hydrophilic material,the adsorption capacity of CR can reached 180.8 mg·g-1,and the recycling rate rose to 94.1%.