Preparation And Desalination Performance Of Electrospun PVDF Composite Nanofibers Membranes For Pervaporation

The global water scarcity is an undeniable fact that must be faced.To solve human water use and increase freshwater resources,a number of approaches have been taken.Among them,desalination is an effective and sustainable method.In recent years,membrane technology has been rapidly developed due to its advantages of energy saving and high efficiency.The pervaporation desalination technology due to it’s high separation efficiency,low energy consumption and other advantages by more and more attention,but there are many difficulties,is still in the research stage.In this paper,the PVDF/PDMS,PVDF/PDMS@NaA organic-inorganic composite membranes were successfully prepared by combining the electrospun nanofibers with the organic coating,and used for pervaporation desalination.The results of SEM,FTIR,TG,DSC and XRD show that the composite membrane has a three-layer structure,and the PVDF nanofiber layer can be well combined with the PDMS coating.The composite membrane retains the advantages of high porosity and chemical resistance of two pure membranes,but is superior to pure membrane in terms of thermal stability and crystallinity.The results of pervaporation desalination showed that the maximum flux of 6.46 L·m^-2·h^-1was obtained at 25℃with 5g/L Na Cl solution for PVDF/PDMS composite membranes,with a rejection of 98.8%.PVDF/PDM@NaA composite membrane,using 5g/L Na Cl solution,the optimum results were as follows:flux 13.89 L·m^-2·h^-1and retention rate 95.8%at the operating temperature of 75℃.The best infiltration results of PVDF/PDM@NaA composite membranes with 35g/L Na Cl solution were:flux of 8.99 L·m^-2·h^-1and retention of 99.05%.The desalination test results show that PVDF/PDMS series composite membranes have better performance and have great application value in pervaporation desalination.