Ultra Filtration

Ultrafiltration (UF) is a variety of membrane filtration in which forces like pressure or concentration gradients leads to a separation through a semipermeable membrane. Suspended solids and solutes of high molecular weight are retained in the so-called retentate, while water and low molecular weight solutes pass through the membrane in the permeate. This separation process is used in industry and research for purifying and concentrating macromolecular (103 - 106 Da) solutions, especially protein solutions. Ultrafiltration is not fundamentally different from microfiltration, nanofiltration or membrane gas separation, except in terms of the size of the molecules it retains - it is defined by the Molecular Weight Cut Off (MWCO) of the membrane used. Ultrafiltration is applied in cross-flow or dead-end mode.