| Membrane bioreactor(MBR) is a efficient wastewater treatment technology with many advantages such as high separation efficiency, high quality effluent, high sludge concentration and high biochemical ability, etc. However, membrane fouling of MBR will reduce separation efficiency and the service life of membrane, increasing the cost of separation. In this paper, regarding to the problem of the membrane fouling and low strength, this paper use organic additives, inorganic additives and organic/inorganic composite additives to prepare casting membrane liquid, by changing the type of casting solution and additives content change ultrafiltration membrane stain resistance and mechanical strength, producing a high strength, stain resistance ultrafiltration membrane.This paper selected the PSF as membrane material, N,N-dimethyl acetamide as organic solvent, Twain80 as surfactant, systematically studied the effect of Polyethylene glycol(PEG), Polyvinyl pyrrolidone(PVP), Lithium chloride(LiCl) and PVP/LiCl as additive on the structure and performance of polysulfone ultrafiltration membrane, discussing different factors such as the types and content of additive, polysulfone content, surfactant content, mixing temperature and coagulation bath temperature and anti-fouling and mechanical strength of ultrafiltration membrane. Studied and determined the suitable preparation process of polysulfone ultrafiltration membrane with high strength and anti-fouling by immersion precipitation phase catalysis to prepare hollow fiber polysulfone ultrafiltration membrane with high strength and anti-fouling. The pure water flux, filtrate rate and fouling resistance were measured by homemade membrane performance evaluation device, scanning electron microscopy(SEM) characterized membrane surface and cross section structure.(1)This chapter studied the various factors systematically affecting the preparation of polysulfone ultrafiltration membrane using polyethylene glycol(PEG) as additive, determined the technological parameters of the preparation-- the content of PSF was 14 wt%, the mixing temperature was 80℃, the content of PEG400 was 15 wt%, the content of Twain80 was 1 wt%, coagulation bath temperature was 35 ℃. Under these conditions, the pure water flux of ultrafiltration membrane was 402.18 L/m2·h, the filtrate rate was 91.76%, membrane resistance increased coefficient was 1.94 and the contact Angle was 84.6°. Therefore, the performance of separation and anti-fouling were better than polysulfone ultrafiltration membrane without additive.(2)This chapter studied the various factors systematically which affects the preparation of polysulfone ultrafiltration membrane using polyvinyl pyrrolidone(PVP) as additive, determined the technological parameters of the preparation-- the content of PSF was 13 wt%, the mixing temperature was 70℃, the content of PVP-K30 was 6 wt%, coagulation bath temperature was 30 ℃. Under these conditions, the pure water flux of ultrafiltration membrane was 902.07 L/m2·h, the filtrate rate was 91.18%, membrane resistance increased coefficient was 1.35 and the contact Angle was 70.5°. Therefore, the performance of separation and anti-fouling were far better than polysulfone ultrafiltration membrane without additive.(3)This chapter studied the various factors systematically which affects the preparation of polysulfone ultrafiltration membrane using lithium chloride(LiCl) as additive, determined the technological parameters of the preparation-- the content of PSF was 14 wt%, the mixing temperature was 80 ℃, the content of LiCl was 2.5 wt%, coagulation bath temperature was 30 ℃. Under these conditions, the pure water flux of ultrafiltration membrane was 480.09 L/m2·h, the filtrate rate was 91.79%, membrane resistance increased coefficient was 2.16 and the contact Angle was 83.4°. Therefore, the performance of separation and anti-fouling were better than polysulfone ultrafiltration membrane without additive.(4)This chapter was based on the study of PVP and LiCl as additive, studied the various factors systematically which affects the preparation of polysulfone ultrafiltration membrane using PVP/LiCl as additive, determined the technological parameters of the preparation: the content ratio of PVP/LiCl was 9:1, the total content of PVP/LiCl was 6 wt%. Under these conditions, the pure water flux of ultrafiltration membrane was 1158.44 L/m2·h, the filtrate rate was 83.22%, membrane resistance increased coefficient was 1.65 and the contact Angle was 80.5°, fouling resistance was excellent.The anti-fouling was worse than the polysulfone ultrafiltration membrane using PVP as additive, but it was better than the polysulfone ultrafiltration membrane using PEG, LiCl as additive and polysulfone ultrafiltration membrane without additive.(5)This chapter was based on previous studies, studied and determined the technological parameters of hollow fiber ultrafiltration membranes using PVP/LiCl as additive, to prepare the external pressure hollow fiber PSF ultrafiltration Membrane with high strength and anti-fouling performance. The pure water flux was 305.47 L/m2·h, the filtrate rate was 91.62%, the breaking strength was 873 cN, the tensile rate was 197%, membrane resistance increased coefficient was 1.86 and the contact Angle was 81.4°, the performance of separation, mechanical and anti-fouling were better than polysulfone hollow fiber ultrafiltration membrane without additive and the internal pressure commercialization polysulfone hollow fiber ultrafiltration membrane. |
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