| With polysulfone commercial membrane as substrate material,Fe3O4/PSF magnetic composite ultrafiltration membrane was prepared.Then the properties of the membrane prepared,such as surface morphology,internal structure and separation performance,were characterized.Effects of iron dichloride concentration,sodium hydroxide concentration,reactive temperature and reactive time on average pore diameter of the membrane prepared were investigated.The result of stability experiment showed that the stability of in situ synthesis method was good in experimental conditions;The result of SEM showed that most particles deposited in the pore of the polysulfone membrane; XRD and XPS analysis indicated that particles deposited in the pore were mainly Fe3O4,and the average particle size of the particles calculated from XRD result was about 6.99nm;The result of XPS indicated that Fe-O-S bond was very likely formed in the magnetic composite ultrafiltration membrane prepared;Liquid-liquid displacement method measured that the average pore size declined from 9.36nm without magnetic field to 8.54nm in magnetic field with the intensity of 0.8T.The rejection to uncharged lysozyme of magnetic composite ultrafiltration membrane rose in magnetic field,while the rejection to charged lysozyme declined in magnetic field.After analysis,we realized that the rejection mechanisms of magnetic composite ultrafiltration membrane in magnetic field consisted of the magnetoinductive effect and magnetostrictive effect.Based on the result of single factor test,the optimum preparing conditions were as follows:iron dichloride concentration 0.2mol/L,sodium hydroxide concentration 2mol/L,reactive temperature 60℃,reactive time 45min.The result of orthogonal test indicated that the effectiveness of factors on the average pore diameter of the magnetic composite ultrafiltration membrane were in this order:iron dichloride concentration＞reactive temperature＞sodium hydroxide concentration＞reactive time.
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