What Is Tangential Flow Ultrafiltration? What Are The Applications?

Tangential flow refers to the filtration form in which the liquid flow direction is perpendicular to the filtration direction.

The traditional liquid dead end filtration, also known as vertical filtration, is a filtration form for most of the microporous filtration, including sterilization and filtration. The direction of the liquid flow is consistent with the filtration direction. With the filtration process, the thickness of cake layer or gel layer formed on the surface of the filter membrane is gradually increased and the flow rate gradually decreases. When the filter medium is ultrafiltration membrane or microfiltration membrane with small pore size and the solid content in the feed liquid is very high, the dead end filtration method will be adopted, and the flow rate will be reduced rapidly. Therefore, the dead end filtration can only deal with small volume of feed liquid.

Tangential flow ultrafiltration is the filtration form of vertical direction of liquid flow direction and filtration direction, that is, the liquid flows along the direction parallel to the membrane, and the surface of the membrane is scoured at the same time, so that the gel layer is not formed on the membrane surface, and the stable ultrafiltration speed is maintained. Widely used in R & D, pilot and industrial production, for larger scale filtration, the tangential flow ultrafiltration method is used to produce shear force on the surface of the filtration medium, which reduces the accumulation of cake layer or gel layer, and ensures a stable filtration rate.

In the biopharmaceutical industry, two types of ultrafiltration systems, membrane encapsulated and hollow fiber, are commonly used according to different membrane modules. Generally speaking, hollow fiber is more suitable for samples with large / dirty particles (such as solid-liquid separation, cell lysate, etc.), while membrane package is more suitable for clean samples (such as protein concentration, sample buffer replacement or protein renaturation, etc.).