Preparation And Properties Of Polyvinyl Alcohol / Intercalated Graphene Oxide Composite Nanofiber Membrane

With the progress of industry and the great development of society,the country's requirements for environmental protection have become more and more stringent.While the textile industry has brought huge economic benefits,it has also brought huge pollution problems.Among them,the large amount of wastewater produced by the printing and dyeing industry causes great damage to the environment,so an efficient and low-cost sewage treatment membrane has become an urgently needed technology for current industrial development.However,the currently used Polyvinyl alcohol filter membrane has low adsorption rate,poor hydrolysis resistance,and poor stretch resistance,which limit its application.In this thesis,combining electrospinning and thermal cross-linking technology,and using polyvinyl alcohol(PVA),nano-silica(Si O₂)as raw materials,and tartaric acid(TA)as cross-linking agent to prepare hydrolysis-resistant PVA/Si O₂ cross-linked nanofiber membranes(P/S-CNM).And on this basis,using Si O₂ intercalated GO as the modified layer of P/S-CNM,using electrostatic spray technology to prepare PVA/Si O₂ intercalated GO composite nanofibers with a sandwich structure(P/S@G-CNM).In addition,the microscopic appearance,chemical structure,tensile properties,thermal properties,adsorption properties of the nanofiber membranes,as well as the retention and anti-pollution properties of the dye wastewater were characterized and analyzed,and the results obtained were good retention,high adsorption,and anti-pollution properties.Sewage treatment membranes with strong pollution performance are summarized as follows:1.P/S-CNM was prepared by electrospinning and heating treatment,mainly to explore the influence of the mass ratio of PVA,Si O₂,and TA on the hydrolysis resistance and adsorption properties.SEM shows that when PVA is 9 wt%and Si O₂ is 4 wt%,the thickness of the PVA nanofibers prepared by the blending method is uniform and there are no doubling filaments and bead-like nodules;when the crosslinking agent TA is 35 wt%,the heat treatment temperature 160?,heat treatment time is 15 min,P/S-CNM has the lowest swelling degree(2.16),mass loss rate(3.4%)is small,hydrolysis resistance is greatly improved,and the tensile performance is increased by 6.5 times;when Methylene Blue(MB)At a concentration of 25 mg·L^-1,the adsorption rate of P/S-CNM can reach 82%.2.P/S@G-CNM was prepared by intercalation of Si O₂ with GO,which mainly explored the influence of different GO and Si O₂ concentration ratios(C_GO/C_{Si O2})on the pitch and tensile properties of GO layers,so as to screen out the best C_GO/C_{Si O2}.The results of electron microscopy showed a three-layer structure,and the Si O₂ intercalation GO functional layer could be observed.When the ratio of C_GO/C_{Si O2} is 6:3,the interlayer spacing of GO increases from 0.805 nm to 0.876 nm,and its tensile properties increase from 7.2 N to 8.1 N.3.Mainly explore the pure water flux,rejection rate,membrane stability,anti-pollution performance of P/S@G-CNM.The test results show that the pure water flux of P/S@G-CNM is increased to 21.05 L·m^-2·h^-1·MPa^-1.The rejection rate of Methylene Blue(MB),Methyl Orange(MO),Congo Red(CR),and Eriochrome Black T(EBT)is above90%,P/S@G-CNM has the advantages of both stability and acid and alkali resistance,and the recovery rate of pure water flux can reach 92%,so P/S@G-CNM has good anti-pollution performance.Further research found that the filtering mechanism of P/S@G-CNM mainly consists of three parts,namely physical size effect,adsorption effect and electrostatic interaction.