Preparation And Characterization Of Highly Hydrophilic Eval Ultrafiltration Membrane Via Combining Immersion Precipitation With Microrolling

Ultrafiltration(UF)is a membrane filtration process between the microfiltration and nanofiltration,and also is a kind of separation technology with different steam pressure as driving force.UF has many advantages,such as high efficiency,low energy consumption,no phase transition,et al.Therefore,UF has been widely used in the fields of aqueous solution processing.However,its development is limited due to its high cost,serious membrane fouling,et al.In order to reach the purpose of polluting resistance,seeking good hydrophilic membrane materials and increasing hydrophilicity of membrane meanwhile is a problem to be solved at present.Firstly,the ethylene-vinyl alcohol copolymer(EVAL)is used as the membrane material,dimethyl sulfoxide(DMSo)is used as the solvent,n-octanol is used as the additive,the pure water is used as non-solvent to prepare the common ultrafiltration membrane only by immersion precipitation.The contact angle tests show that the contact angle of the membrane surface with water is 41 °,showing hydrophilicity.Then,a preparation method of highly hydrophilic EVAL ultrafiltration membrane is proposed-combing immersion precipitation with microrolling and roll on the surface of the semi-coagulation membrane and the common ultrafiltration membrane after eroded by the erosion agent respectively.In the semi-coagulation-micro-rolling experiment,after determining the semi-coagulation bath,we use the gel kinetics experiment to predict the semi-coagulation time preliminarily.It is found that the membrane fluid experiences the process of diffusion-mass transfer-physical telescopic deformation(caused by polymer chain motion and molecular relaxation).The period of final mass transfer to the physical telescopic deformation is selected for semi-coagulation time.Finally,the membrane contact angle is as low as 10°.In the erosion-rolling experiment,common ultrafiltration membrane need to be eroded by the DMSo aqueous solution in two ways: spray erosion and immersion erosion.After eroding the membrane surface,the membrane is rolled and then immerse the coagulation bath to obtain a highly hydrophilic ultrafiltration membrane with a contact angle of 12°...