Ultrafiltration (commonly abbreviated as UF) is a variety of membrane filtration in which forces like pressure or concentration gradients lead to a separation through a semipermeable membrane.
Suspended solids and solutes of high molecular weight are retained, while water and low molecular weight solutes pass through the membrane in the permeate (filtrate). Ultrafiltration is not fundamentally different from microfiltration.
Both separate based on size exclusion or particle capture. Ultrafiltration membranes are defined by the molecular weight cut-off (MWCO) of the membrane used. Ultrafiltration is applied in cross-flow or dead-end mode.
The basic operating principle of ultrafiltration uses a pressure induced separation of solutes from a solvent through a semi permeable membrane.