The Preparation And Characterizations Of Novel Positively Charged Asymmetric Membranes

Charged membrane is the membrane that has the inherent charges on the membrane surface. The hydrophilicity of the charged membrane is enhanced due to the introduction of the charged groups. Thus, the permeability of the membrane is increased as well. Furthermore, charged membrane can be used to separate charged component with much smaller size than pore size according to electrostatic repulsion. By controlling the pore size, charge species and charge density, the separation of different ions and chemical reaction can be realized. Therefore, charged membrane is attached importance to application in recycling resource and protecting environment.Driven by commercial interests, the negatively charged membrane used for antifouling in the separation of biochemical products has been deserved much attention in recent years. The development of the positively charged membrane is ignored due to its difficulty in preparation. But to separate the species with positive charge such as the separation of bio macromolecules below the isoelectric point, and recover cathode electrophoresis lacquer, etc., positively charged is actually indeed.This dissertation includes six chapters. A series of positively charged asymmetric membrane are prepared by in situ amination and phase inversion in which the organic solution of tertiary amine and brominated PPO were cast and immerged into coagulation medium. The influence of the membrane preparation parameter, such as the proportion of the polymer to amine, charged group species, the concentration and the molecular weight of the PEG additives, as well as the membrane forming conditions on the membrane performance and microstructure have been investigated.Chapter I gives an overview on the research background through the introduction of the preparation and separation mechanism of the charged membrane, and generalization the research status of the positively charged membrane. Then the membrane preparation by phase inversion method (includes the process of the membrane forming and the influence parameters of the membrane performance), the properties of poly (2,6-dimethyl-l,4-phenylen oxide) (PPO) and its application in membrane preparation are elucidated. Finally, the research ideas and outline of the...