Preparation Of Macromolecular Grafted PAN Nanofiltration Membrane By Microphase Separation And Its Properties

According to the bionics principle,a casting solution was prepared by grafting of acrylonitrile?AN?onto silk fibroin?SF?in ZnCl₂ aqueous solution.SF grafted PAN?SF-g-PAN?filtration membrane was fabricated by phase inversion in water.The formation of membrane pores results from diffusion of the zinc and chloride ions into the water in phase change process.The hydrophilic channel were formed by microphase separation between silk fibroin and PAN.The narrow pore size distribution and good hydrophilicity of SF-g-PAN filtration membrane solved the contradiction between filtration precision and precision.The membranes were characterized by SEM,FTIR,TG-DTG and water contact angle.The membrane filtration performance were studed by the rejection and flux of different molecular weight dyes and the results indicated that the SF-g-PAN membranes have characteristics of fine separation,dye desalination and pH-responsive.The rejection of SF-g-PAN membranes on the Direct yellow 27?Mw=662.62 Da?was 96%above.However,the rejection of Amaranth red?Mw= 604.47 Da?was 30%.The flux of BSA solution was about 86.39%of PWF.The result showed SF-g-PAN membranes have anti-fouling performance.The dextran grafted PAN?De-g-PAN?filtration membrane was prepared by phase inversion in water.Dextran grafted PAN was synthesized using dextran as polymer skeleton,AN as monomer in the ZnCl₂ solution.SEM,FTIR,TG-DTG and water contact angle test were used to characterize the De-g-PAN filtration membrane.The content of dextran on the rejection and flux of membrane on different molecular weight dyes showed that the membrane have good rejection rate for the dyes?Mw?660?,and with the increase of the content of dextran,the rejection rate of the filtration membrane on the dyes was increased,and the flux decreased.BSA solution and oil emulsion were used to investigate its anti-fouling performance.The increase of content of dextran improved the anti fouling property of the membrane.It was found that the PAN played a major role in the filtrating process.Therefore,the filtration performance of membranes preparated by two different methoths were investigated.The PAN filtration membranes with different structures were prepared by two different solvent?ZnCl₂ and DMF?.The surface and cross-section morphology of membranes under both dry and wet condition were observed by SEM,3D ultra-depth microscope and Laser scanning confocal microscope.The structural performances of tow kinds of membranes were compared using XRD,water contact angle and mechanical behavior.The rejection and flux of tow kinds of membranes on different molecular weight dyes demonstrated narrow pore size and good anti-fouling performance of PAN membrane prepared using the ZnCl₂ as solvent.