| In this paper, the structure and properties of Polyurethane (PU)-SiO2, Polyethersulfone(PES)-SiO2 composite membrane. including composite flat membrane and composite hollow fiber membrane, and responsivity of composite PU hollow fiber membrane pore size to pressure were studied.The studies on stability of PU-SiO2, PES-SiO2 suspensions and influence coagulant bath temperature on flat membrane were carried out. The results indicate the even blended, clear suspensions owned a good stability and flowability, and can used as casting membrane solutions. Both the stability of active carbon power suspensions and the integration properties of membrane being made from them were bad. Coagulant bath temperature had a strong influence on PU, PES composite flat membrane. If coagulant bath temperature was too high, flat membranes would have presented themselves with all kinds of defects. When coagulant bath temperature was at 15 C, the flat membrane was smooth, and the defects disappeared.The determination of the cloud point of PU-SiO2, PES-SiO2 suspensions was obtained by titration. The results showed that the addition of Si02 with a high specific surface made polymer chains adsorbed at the surface, influenced the phase behavior of suspensions, shifted the bimodal to lower nonsolvent concentrations, and the water tolerance became bad.The studies on the influence addition of SiO2 on structure and properties of PU, PES membranes were fulfilled. The results showed that the addition of SiO2 resulted in acute enhancement of pure water flux combined with unchanged rejection properties, and the improving factor of PES membrane flux was above 4. This is due to three reasons: (1)SiO2 influenced the phase behavior of suspensions, shifted the bimodal to lower nonsolvLTil concentrations, so that it changed the skin characteristics and pore structure. (2)There was a kind of interfaeial micro-void (this is thespaces between the phase of polymer matrix and distributive SiO2 particles or CA phase) existing in the membrane. This enhanced interconnectivity of the membrane pores. (3)A lot of Si-OH existing in the surface of SiO2 improved the hydrophilicity of composite membrane.The adsorption of polymer chains at the SiO2 surface avoided the coherence between the nascent hollow fibers, improved spinning conditions and hollow fiber bearing. The addition of CA further improved mechanical property of membrane, but pressure-resiposivity became weak.By controlling polymer and SiO2. concentrations, bore flow rate, dope solution temperature, coagulant bath temperature, 5 types of composite PU hollow fiber membranes were prepared. The recovery extent of different composition hollow fiber membrane pore size is different. The ability to recover of type. 1, type. 2 and type. 3 were weak. Compared with them, type. 4 and type. 5 have a better recovery.The flux-transmembrane pressure curves of several kinds of PU composite hollow fiber membranes differed completely from non-deformation membranes, deviated from the linear relation obviously. This strongly indicated that, due to PU characteristics, such as good elasticity and strong recovery, PU-SiO2 composite hollow fiber membranes have a comparatively good pressure-responsivity. This is to say, PU composite hollow fiber membranes pore size can become large with transmembrane pressure increasing, and can recover completely with transmembrane pressure reverting to original pressure at a specification condition.From the Hagen-Poiseuille equal ion, PU composite hollow fiber membrane pore radius magnification was calculated. In our experiment, the variation of membrane pore radius attained to much six times larger than the primitive membrane pore radius. In addii ion, the pressure-responsivity of type 3, 4, 5 was different due to the variation of SiO2 content. SiO2 play an important role to pressure-rvsponsi vity of PE composite hollow fibermembranes.Oil-water emulsion was treated using as-spun PU composite ho] low fiber membranes. The flux decline was very severe compare...
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