The membrane filtration method using an ultrafiltration membrane with a pressure difference as a driving force is ultrafiltration membrane filtration. Ultrafiltration membranes are mostly made of acetate fibers or polymer materials with similar properties. It is most suitable for the separation and enrichment of solutes in solution, and is also commonly used for the separation of colloidal suspensions that are difficult to accomplish by other separation techniques, and its application fields are expanding.
Membrane filtration driven by pressure difference can be divided into three types: ultrafiltration membrane filtration, microfiltration membrane filtration and reverse osmosis membrane filtration. Their distinction is based on the minimum particle size or molecular weight that the membrane layer can trap. When the nominal pore size range of the membrane is used as a classification standard, the pore size range of the microporous membrane (MF) is 0.02 to 10 μm; the ultrafiltration membrane (UF) is 0.001 to 0.02 μm; and the reverse osmosis membrane (RO) is 0.0001 to 0.001 μm. It can be seen that the ultrafiltration membrane is most suitable for the separation and enrichment of solute in the treatment solution, or the separation of the colloidal suspension which is difficult to accomplish by other separation techniques. The membrane forming technique of ultrafiltration membranes, that is, the technique of obtaining the desired size and narrow distribution of micropores is extremely important. There are many control factors for the pores. For example, ultrafiltration membranes with different pore sizes and pore size distributions can be obtained according to the type and concentration of the solution during the film formation, evaporation and coagulation conditions. The ultrafiltration membrane is generally a polymer separation membrane, and the polymer materials used as the ultrafiltration membrane mainly include cellulose derivatives, polysulfones, polyacrylonitrile, polyamides, and polycarbonates.
Ultrafiltration membranes are widely used in food industry, pharmaceutical industry, etc., and can be used as concentrated purification of medicines, juices, dairy products, etc., purified water, mineral water purification, etc. Ultrafiltration equipment has good filtration effect, large water output and strong stability. Features.