| Membrane fouling is one of the obstacles which limit severely membrane technology to be applied widely in liquid separation. One efficient approach is to modify the hydrophilic property of membranes. On the basis of the rapid development of nano-technology, a new way is opened up for overcome this problem. The author of this dissertation used polyaniline (PANI) nanofibers as the functional component to improve the hydrophilic property of polysulfone (PSf) materials by blending, while the immersion-phase inversion method was adopted to prepare the blended membrane. PANI/PSf blended membranes with excellent hydrophilic and anti-fouling properties were obtained.The effects of several basic factors in preparing process on morphology and performances of blended membrane were explored. DMAc was chosen as the solvent. Blended membrane had higher rejection and lower pure water flux with increasing PSf content, and the optimal mass ratio of PSf to total blended solution was 15~18%. When the coagulation-bath component diverted from pure water to 50% ethanol, 100% ethanol and 100% isopropanol, blended membrane went to compact structure and the permeability declined gradually. In the investigative scope the blended membrane with 20℃coagulation-bath temperature showed higher permselectivity. PVP was proved to be an efficient additive, which could enhance the porosity and pure water flux of blended membrane without selectivity falling. Blended membrane had lower permeability with prolonging pre-evaporation time and increasing casting thickness. However, too short pre-evaporation time and too thin casting thickness will lead to membrane defect. Thus, the appropriate pre-evaporation time and casting thickness were 30 seconds and 250~300μm respectively.The influences of PANI nanofiber content, nanofiber morphology and doped-dedoped states of PANI on structure and performances of blended membrane were investigated. With adding PANI nanofiber in the casting system, the thermodynamics instability became strengthened which was illuminated by the cloud-point phase diagram, the viscosity of casting solution became higher and the type of fluid turned from Newton to non-Newton. Compared with pure PSf membrane, blended membranes (mass ratios of PANI: PSf were 1:100 ~15:100) displayed a little larger pore size, higher porosity, better hydrophilic property and connectivity of pores. Blended membranes with different PANI contents showed 1.6~2.4 times pure water flux as high as that of pure PSf membrane with similar BSA, AE and PEG-35K rejections. During the filtration of BSA solution, blended membranes presented higher permeate flux, flux retention and flux recovery after simple water flush, all of which testified a remarkable anti-fouling property. With the rise of PANI nanofiber content, breaking strength increased and elongation ratio at break decreased gradually. Blended membranes showed an obvious predominance of thermal stability over pure PSf membrane in higher scope of temperature. In addition, blended membrane using shorter PANI nanofiber had higher pure water flux and porosity, better hydrophilic and anti-fouling properties than using the longer one. In acid condition blended membrane surface had positive charge attributed to PANI at doped state, while in alkalescence condition blended membrane surface had no charge because of PANI at dedoped state. Blended membrane with PANI at doped state showed a little lower pure water flux, higher rejection and flux retention during the filtration of BSA solution than that with PANI at dedoped state.
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