Semipermeabiili

Semipermeabiili is a term derived from the Latin words "semi" meaning half or partial, and "permeare" meaning to pass through. It describes a property of a membrane or barrier that allows certain molecules or ions to pass through it by diffusion, and occasionally specialized facilitated transport, but not others. This selective permeability is crucial for many biological and chemical processes.

In biology, cell membranes are prime examples of semipermeable barriers. They control the movement of substances into and out of cells, regulating the internal environment. This allows essential nutrients to enter while expelling waste products and preventing harmful substances from entering. The process of osmosis, the movement of water across a semipermeable membrane from an area of higher water concentration to an area of lower water concentration, is a direct consequence of semipermeability.

In chemistry and industrial applications, semipermeable membranes are used in processes like reverse osmosis for water purification, where pressure is applied to force water molecules through the membrane, leaving behind dissolved salts and other impurities. Dialysis, both in medical settings and in laboratory equipment, also relies on semipermeable membranes to separate molecules based on their size and ability to pass through the membrane. The degree of permeability can vary significantly between different semipermeable materials, influencing their suitability for specific applications.