Preparation of Porous Poly(Vinyl Butyral)-Tio2 Composite Hollow Fiber Membrane for Drinking Water Treatment
Hideto Matsuyama, Department of Chemical Science and Engineering, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe, Japan and Fu Xunyao, Department of Chemival Science and Engineering, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe, Japan.
Membrane separation technology has been becoming an important method in water treatment. However, membrane fouling is a serious problem occurred in water treatment process. It is well known that the hydrophilicity of membrane surface is crucial to reduce the membrane fouling. Previously, we investigated the preparation and characterization of poly (vinyl butyral) (PVB) hollow fiber membranes. The water contact angle of the obtained PVB membrane was about 60°, which was lower than that of membranes made by hydrophobic materials such as polyethylene or poly (vinylidene fluoride). However this hydrophilicity is not necessary enough to prevent the membrane fouling. A new approach to modify PVB membrane by addition of Titanium dioxide (TiO2) is under our study. TiO2 has been focused on its photocatalytic activity, high hydrophilicity and stable chemical property in numerous investigations recently. In this work, PVB- TiO2 composite hollow fiber membranes were prepared via nonsolvent induced phase separation (NIPS) method. TiO2 particle has the property that makes the surface to be hydrophilic by the irradiation of UV. The effect of TiO2 on membrane properties such as water permeability, membrane strength, morphology and water contact angle were investigated. In the membrane preparation, the weight ratio of TiO2 to PVB changed from 0.1 to 1, while the PVB concentration was kept to be 15wt%. Though the water permeability hardly change with the addition of TiO2, the tensile strength and elasticity increased. When PVB concentration is 10wt%, the weight ratio of TiO2 to PVB changed from 1 to 2. The water permeability increased with the increase of TiO2 content. Furthermore, for all of the membranes, with the elapse of time, the water permeability increased, and it became to be constant after about 15days. In addition, for PVB-TiO2 membrane, the water contact angle on the membrane surface decreased after the irradiation of UV, which means that the surface of the composite membrane became to be more hydrophilic. Such a phenomenon didn't take place for the PVB membrane without TiO2.