Semi-permeable membranes - Ultrafiltration membranes

An ultrafiltration membrane is a porous, organic or inorganic, anisotropic (asymmetric) or composite artificial membrane.

The thin layer, or active layer, or skin, which is thin (around 10 µm) and contains mesopores, is supported by one or more more more porous and mechanically stronger layers, the whole having a thickness of around 150 µm, for example in the case of organic membranes. In the case of an anisotropic membrane, the skin is supported by a medium of the same nature but with larger pores, ensuring easy drainage and good mechanical strength.