Preparation And Application Of Magnetic Composite Based PVDF Functional Films

With the rapid improvement of social environment awareness made people deeply realized the harmful effects of dye wastewater,heavy metal ions and oily waste liquid on the human environment,and membrane separation technology could solves the above problems.Among many polymers,PVDF(polyvinylidene fluoride)film is favored by many scientific researchers because of its outstanding chemical properties.However,due to its natural hydropHobic properties,it is easily contaminated by organic matter in practical applications.Therefore,in order to be widely used in practice,the first step is to modify it which improves its hydropHilic properties.Therefore,it is of great significance to develop new,manufacturing simple and good separation membranes.In view of the blending modified PVDF membrane has the characteristics of simple operation and performance superior.in this paper,the blending method and blending method under magnetic field conditions were used to improve the membrane hydropHilic performance,meanwhile preparing a composite membrane with strong anti-pollution performance and high separation efficiency.In this paper,a double-layer core-shell composite matetial with halloysite nanotubes as the framework and triiron tetroxide as the intermediate layer,DA and APTES as the derived layer were prepared and characterized by FT-IR,XRD,TGA and TEM.It was added to the PVDF membrane and blended modification,the surface of the membrane was studied by FT-IR,SEM,AFM and EDS.In addition,the hydropHilicity,pure water flux,membrane radius and porosity,anti-pollution performance and BSA rejection of the membrane were evaluated.The membrane was found to have strong hydropHilicity,high BSA rejection and strong anti-pollution.Finally,it was applied to the separation of methylene blue wastewater and oil-water emulsion wastewater.The experimental results show that the modified membrane has high separation efficiency and could be used in practice for a long time.This article also applied ethylenediamine graft ?-Cyclodextrin,which modified Fe3O4/GO to obtain magnetic composite material ?-MGO(?-cyclodextrin magnetic grapHene),and characterized by FT-IR,XRD,TEM,Raman,XPS and VSM.In the experiment,the excellent performance of the magnetic composite material was fully exerted,which is not only the easy magnetic separation performance but also the PVDF film was modified under the magnetic field condition,and the magnetic composite material was adsorbed to the film surface by the magnetic field force under the magnetic field condition.The effects of magnetic field on the retention of BSA,hydropHilicity,pure water flux and surface morpHology of the composite membrane were discussed.The surface structure and chemical components of the modified membrane were studied by FT-IR,SEM,EDS,AFM and XPS.Finally,it was applied to the separation of Cu2+ waste liquid.It was found that the composite membrane prepared under the magnetic field condition and the blended membrane prepared without magnetic field conditions had little difference in Cu2+ rejection rate.However,the water flux of the composite membrane under magnetic field conditions has been greatly improved,which means that the composite membrane prepared under magnetic field conditions not only maintains high rejection but also has a large flux.This greatly improves the processing efficiency of the composite film in practice.Finally,the effects of PH,initial concentration and contact time on the Cu2+ separation of the composite membrane prepared under magnetic field conditions were discussed.In addition,the composite membrane was found to maintain high separation efficiency in the experiments of multiple separation of Cu2+wastewater.