Preparation And Performance Of A New Type Of Hollow Membranes For Sewage Treatment Application

This paper presented the results of investigation concerning the formation, structure and transport properties of fiber membranes made of polymer vinyl chloride and thermoplastic Polyurethane. DMAC was used as solvent. The miscibility of the polymer blends PVC and TPU was discussed. Furthermore, effects of dope composition and temperature, composition of coagulation bath and spinning conditions on structures and properties of PVC/TPU hollow fiber membranes were also investigated. At last, the stability of PVC/TPL hollow fiber membranes was discussed. The porosity of the PVC/TPU membranes was determined by SEM observations and porosity, the transport separation properties of membranes were determined by measuring the water flux and retention coefficient of BSA solution.Results stated that the polymer blends PVC and TPU were partial miscibility. The structures of membranes could be controlled by changing the ratio and concentration of polymers in the casting solution, by using PEG, PVP, Tween-80 as additives to the casting solution and the composition and temperature of coagulation bath. When the miscibility of polymer was better, a co-blend membrane with greatly improved flux or retention would be obtained. The condition of the coagulation bath is a very important factor and decides the morphology of the microporous membranes by phase-conversion process. We changed the composition of core liquid and replaced with ethanol solution or add solvent DMAC into core liquid, then we observed that the holes of interior wall were changed into crackle holes from round holes. It was also observed that the morphology of the obtained membranes, which could be sponge-like or both finger-like and sponge-like depended on the condition of coagulation bath used. Thechemical stability of PVC/TPU mixture membranes was very excellent. Results also indicated blended membranes had high water flux, a good intensity, low price, pressure-opposed and high elastic performance, so could be suitable for application in the sewage treatment.Zhu yamin (Environment engineering) Supervised by Professor Xi Danli...