| Membrane separation technology is a new and interdisciplinary separation. Compared with the traditional separation processes, membrane separation with high efficiency, energy saving, no secondary pollution, continuous operation at room temperature, especially suitable for thermal treatment of substances, changes in size and capacity, low operation cost, equipment size small and high reliability. Therefore, in chemical, electronics, light industry, food processing, medicine, metallurgy, petrochemical and other industries have wide applications.The film has already been industrialized process, microfiltration plays a decisive role. Microfiltration largest market share and most versatile.PTFE, PVDF, polypropylene, cellulose acetate, nitrocellulose, polyvinyl chloride, polyamide, polycarbonate, etc. can be used as preparation of microporous polymer membrane. But the application of microporous membranes of goods are still high cost, poor drainage, poor acid and alkali resistance, chemical stability of the disadvantages such as poor and low porosity, the use is restricted. Therefore the development of a low cost, chemical stability and thermal stability, good performance membrane separation membrane researchers as problems to be solved.Suitable microporous filter membrane material aperture range of 0.01 ~ 10um, method of preparation of microporous membranes main phase inversion method, stretching, sintering and the nuclear track method. One nuclear track membrane prepared by a narrow pore size distribution, uniform pore size, but low porosity and restriction of membrane material. Other methods of preparation of the final membrane pore size distribution is very wide, often a film the difference between macroporous and holes up to several hundred times, and the preparation method is rather complicated.Preparation of this paper, porous paper support layer manufacturing process, use of different film materials using mature manufacturing process of composite preparation of a paper copy of composite porous membrane. Plant fiber lower prices, reduce production costs microporous membrane, and plant fiber is a renewable resource, but also played a role in environmental protection.In this research, paper serves as the base membrane of MF composite membrane, and suitable membrane materials were selected and coated on the surface of base membrane to prepare MF composite membrane.Through the study influence of the kind of pulp, the way of beating free pulp, the degree of beating, base weight and calender on on pore diameter, porosity and water flux, 10oSR paper with 90 g/m2 base weight was selected as base membrane. Serials of membrane materials were coated on the base membrane to make composite membranes and their properties were tested, among which bacterial cellulose and high beating pulp were selected as coating materials. MF composite membranes were made in methods of filtration-composite and mixing-composite. After the optimized properties made of these composite membranes were compared, bacterial composite membrane with 6g/m2 has the best properties.The physical-chemical properties of bacterial cellulose composite membrane and its application effect were also studied. The study showed the composite membrane gave good performances with 95.82% interceptive rate of GCC and 94.3% removal rate of yeast. In the aspect of physical-chemical properties, the membrane had good strength and resistance to alkaline and high temperature but relatively weak acid tolerance.The SEM picture of bacterial cellulose membrane showed the thin-film was formed on the surface of base membrane by coating membrane material, pore diameter was 0.1~0.2um. In addition, limited numbers of micro-pore resulted in relatively low penetrating flux. The formation of surface thin-film was analyzed and describe as the sol-gel process with the evaporation of solvent. The variation tendency of interceptive rate and water flux with time demonstrated the filtration process of membrane agreed with the"screening"mechanism.
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