| Bacterial cellulose is a kind of high purity of cellulose, which is based on the production of gluconacetobacter xylinum strain. Compared to the cellulose exist in nature, bacterial cellulose have high purity, high crystalline, strong water absorption, high tensile strength and biocompatibility. The main structure features of bacterial cellulose fiber bundles for the nano-scale entanglement with a random arrangement of the three-dimensional network-like. Based on the structure, the preparation of bacterial cellulose membrane is a new research filed.In this work, the preparation and performance of bacterial cellulose membrane were studied. BC / Chitosan composite film was prepared with the chitosan cross-linked bacterial cellulose, Moreover, BC / PVA blend composite membrane was prepared by homogenized bacterial cellulose and blending PVA. Using bovine serum albumin as a separate object, the macromoleculesto separation of two kinds of membrane were examined. The research works are as follows:1. Different concentrations of chitosan on bacterial cellulose membrane cross-linking were researched. Chitosan molecules enhanced the mechanical properties of bacterial cellulose membranes by the hydrogen bonding. When the chitosan content was 2%, the tensile strength of the composite membrane reached 73MPa. With the increase of concentration of chitosan , the membrane flux, pore size and porosity radiate trend to decrease.2. The separation properties for metal ions and bovine serum albumin were investigated. The chitosan concentration, water pressure and filtration time on the performance of membrane separation were investigated. The results show that the membrane performed a bad separation ability on metal ions, but a good separation ability on bovine serum albumin. With the increase of chitosan concentration and the water pressure, the rejection ratio of bovine serum albumin increased. And with the time extended, the flux declined, but the rejection ratio increased. The best process condition was confirmed: the chitosan concentration is 2wt%, the pressure is 0.2MPa and the filter time is 20min.3. Homogenate treated bacterial cellulose membrane and PVA composite membranes were prepared by blending. As a structure of bacterial cellulose gel, PVA gel present widely in the formation of particles. The combination of the structure works with hydroxyl and carboxyl groups through hydrogen bonding. When the proportion of BC / PVA is 5:1, the tensile strength reaches 26 MPa.4. The PVA concentration, filtration pressure and filtration time on the BC / PVA blend composite membrane filtration of bovine serum albumin were studied. The higher of the PVA concentration, the higher retention rate and the filtration pressure of the composite membrane stands for a better flux of bovine serum albumin; when the pressure increased, the higher retention rate was slowed. And when the filtration time increased, the filtration performance of blend membrane was degraded. When the BC / PVA was 5:3, the composite film has a good filtering performance.5. The effect of membrane cleaning and regeneration the BC / Chitosan composite film and the BC / PVA blend composite membranes were studied by using NaOH solution. Because with different combination ways, BC / Chitosan composite membrane have a flux recovery after a relatively short time(<30min), while the BC / PVA blend composite film has a better recovery in a long time. After 120min cleaning, the WFR (Water Flux Recovery) of two composite membranes were of 84% and 89% respectively.
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