The process characteristics of ultrafiltration membranes are membrane filtration with pressure difference as the driving force, which can be divided into three categories: ultrafiltration membrane filtration, microporous membrane filtration and reverse osmosis membrane filtration. Their distinction is based on the size or molecular weight of small particles that can be retained by the membrane layer. When the rated pore size range of the membrane is used as the criterion, the rated pore size range of the microporous membrane (MF) is 0.02 ~ 10μm; the ultrafiltration membrane (UF) It is 0.001 ~ 0.02μm; Reverse Osmosis Membrane (RO) is 0.0001 ~ 0.001μm.
It can be seen that the ultrafiltration membrane is more suitable for the separation and concentration of solutes in the treatment solution, or the separation of colloidal suspensions that are difficult to accomplish by other separation techniques. Ultrafiltration membranes are generally polymer separation membranes. The polymer materials used for ultrafiltration membranes are mainly cellulose derivatives, polysulfone, polyacrylonitrile, polyamide and polycarbonate. Ultrafiltration membranes can be made into flat membranes, rolled membranes, tubular membranes or hollow fiber membranes, and are widely used in pharmaceutical industry, food industry, environmental engineering, etc.