The form of the membrane may be either solid or liquid; the fluid substance separated by the membrane may be liquid or gaseous.
The membrane has at least two interfaces, and the membrane contacts and passes through the two sides of the fluid separated by the two interfaces.
The separation film can either be completely permeable or semi permeable, but not completely impermeable.
Membrane separation is based on components with selective function through the membrane as the separation medium, by applying on the two sides of the membrane (or existence) of one or more driving force, the raw materials in the membrane fractions selectively and preferentially through the membrane, so as to achieve separation, and achieve a new separation process of extraction, concentration, product the purpose of purification.
