What is Tangential Flow Ultrafiltration? What are the applications?
Tangential flow refers to the form of filtration in which the direction of liquid flow is perpendicular to the direction of filtration.
Traditional liquid dead-end filtration, also called vertical filtration, is the filtration form adopted by most microporous filtration, including sterile filtration. The flow direction of the liquid is consistent with the filtration direction. The thickness of the filter cake layer or gel layer increases gradually, and the flow rate decreases gradually. When the filter medium is an ultrafiltration membrane or microfiltration membrane with a small pore size, when the solid content in the feed liquid is high, the dead-end filtration method will reduce the flow rate rapidly, so the dead-end filtration can only process small volumes of feed liquid.
Tangential flow ultrafiltration refers to the filtration form in which the liquid flow direction is perpendicular to the filtration direction, that is, the liquid flows in a direction parallel to the membrane, and the surface of the membrane is washed while filtering, so that no condensation will form on the surface of the membrane. The glue layer maintains a stable ultrafiltration rate. It is widely used in research and development, pilot test and industrial production. For large-scale material liquid filtration, the tangential flow ultrafiltration method is adopted. The liquid flow generates shear force on the surface of the filter medium, which reduces the filter cake layer or gel. The accumulation of layers ensures a stable filtration speed.
In the biopharmaceutical industry, according to the different membrane modules, two types of ultrafiltration systems are commonly used: membrane pack type and hollow fiber type. Generally speaking: hollow fibers are more suitable for larger/dirtier samples (such as solid-liquid separation, cell lysate, etc.), while membrane cassettes are more suitable for cleaner samples (such as protein concentration, sample buffer exchange or protein renaturation) Wait).
