Ultra-filtration (UF) is a membrane separation technology that purifies and separates solutions. The

ultrafiltration membrane system is a solution separation device in which an ultrafiltration membrane is

used as a filter medium and a pressure difference on both sides of the membrane is a driving force. The

ultrafiltration membrane only allows the solvent (such as water molecules), inorganic salts and small

molecular organic substances in the solution to pass through, and the macromolecular substances such

as suspended matter, colloid, protein and microorganisms in the solution are intercepted, thereby

purifying or separating.

Ultrafiltration membranes are used extensively in water treatment projects. Ultrafiltration technology plays

an increasingly important role in the fields of reverse osmosis pretreatment, drinking water treatment, and

reuse of water. Ultrafiltration technology plays a key role in the sterilization and turbid removal of alcohol

and beverages, the depyrogenation of pharmaceuticals, and the concentration of foods and

pharmaceuticals.

The form of the ultrafiltration membrane can be divided into two types, a plate type and a tube type. The

tubular ultrafiltration membrane is further classified into hollow fiber, capillary tube and tube type

according to the diameter of the tube. The ultrafiltration membranes used for water treatment on the

market are basically capillary type, and the hollow fiber (inner diameter 0.1-0.5 mm) polyethylene or

polypropylene microporous membrane used in individual projects should actually belong to the

microfiltration membrane.

The assembly of ultrafiltration membrane filaments into a module that can be coupled to an ultrafiltration

system is referred to as an ultrafiltration membrane module. The ultrafiltration membrane modules are

classified into three types: internal pressure type, external pressure type and submerged type. The

driving force of the immersion ultrafiltration membrane filtration is the pressure difference between the

vacuum inside the membrane tube and the atmospheric pressure. For ultrafiltration membranes with high

filtration accuracy, this pressure difference is usually not easy to meet the required filtration driving force,

so the submerged component form is suitable for ultrafiltration membranes or microfiltration membranes

with low filtration precision. When the external pressure type ultrafiltration is used in the forward and

reverse strokes, the flow rate of the liquid on the surface of the membrane is extremely uneven, which

affects the flushing effect on the surface of the membrane. Therefore, the ultrafiltration membrane

commonly used for water treatment or the internal pressure type component structure has advantages.