Scheme of semipermeable membrane during hemodialysis, where red is blood, blue is the dialysing fluid, and yellow is the membrane.

A semipermeable membrane, also termed a selectively permeable membrane, a partially permeable membrane or a differentially permeable membrane, is a membrane which will allow certain molecules or ions to pass through it by diffusion and occasionally specialized "facilitated diffusion". The rate of passage depends on the pressure, concentration and temperature of the molecules or solutes on either side, as well as the permeability of the membrane to each solute. Depending on the membrane and the solute, permeability may depend on solute size, solubility, properties, or chemistry. An example of a semi-permeable membrane is a lipid bilayer, on which is based the plasma membrane that surrounds all biological cells. Many natural and synthetic materials thicker than a membrane are also semipermeable. An example of this is the thin film on the inside of an egg. Image File history File links Please see the file description page for further information. ... Image File history File links Please see the file description page for further information. ... It has been suggested that Artificial kidney be merged into this article or section. ... 3D (left and center) and 2D (right) representations of the terpenoid molecule atisane. ... This article is about the electrically charged particle. ... diffusion (disambiguation). ... facilitated diffusion in cell membrane, showing ion channels and carrier proteins Facilitated diffusion (or facilitated transport) is a process of diffusion, a form of passive transport, where molecules diffuse across membranes, with the assistance of transport proteins. ... This article is about pressure in the physical sciences. ... For other uses, see Concentration (disambiguation). ... For other uses, see Temperature (disambiguation). ... A substance is soluble in a fluid if it dissolves in the fluid. ... Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. ... This fluid lipid bilayer cross section is made up entirely of phosphatidylcholine. ... Drawing of a cell membrane A component of every biological cell, the cell membrane (or plasma membrane) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... In most birds and reptiles, an egg (Latin ovum) is the zygote, resulting from fertilization of the ovum. ...

One example of a semipermeable membrane is a phospholipid bilayer, a group of phospholipids (consisting of a phosphate head and 2 fatty-acid tails) arranged into a double-layer, with the hydrophilic phosphate heads exposed to the water content outside and within the cell and the hydrophobic fatty-acid tails hidden in the inside. The phospholipid bilayer is the most permeable to small, uncharged solutes. Protein channels float through the phospholipids, and collectively, this model is known as the fluid mosaic model. A DPPC bilayer simulation Color scheme: PO4 = green, N(CH3)3 = violet, water = blue, terminal CH3 = yellow, O = red, glycol C = brown, chain C = grey In biology and chemistry, a lipid bilayer is a membrane or zone of membrane composed only of lipid. ... Two schematic representations of a phospholipid. ... Drawing of a cell membrane A component of every biological cell, the cell membrane (or plasma membrane) is a thin and structured bilayer of phospholipid and protein molecules that encapsulate the cell. ...

In the process of reverse osmosis, Thin film composite membranes (TFC or TFM) are used. Thin film composite membranes are semipermeable membranes manufactured principally for use in water purification or desalination systems. They also have use in chemical applications such as batteries and fuel cells. Essentially, a TFC material is a molecular sieve constructed in the form of a film from two or more layered materials. Reverse osmosis is a separation process that uses pressure to force a solvent through a membrane that retains the solute on one side and allows the pure solvent to pass to the other side. ... Thin film composite membranes (TFC or TFM) are semipermeable membranes manufactured principally for use in water purification or desalination systems. ... Control room and schematics of the water purification plant to Bret lake. ... Shevchenko BN350 desalination unit situated on the shore of the Caspian Sea. ...

Membranes used in reverse osmosis are typically made out of polyimide, chosen primarily for its permeability to water and relative impermeability to various dissolved impurities including salt ions and other small molecules that cannot be filtered. Another example of a semipermeable membrane is dialysis tubing. Polyimide (sometimes abbreviated PI) is a polymer of imide monomers. ... Dialysis tubing size comparison with that of a quarter Dialysis Tubing is a type of semi or partially permeable membrane tubing made from regenerated cellulose or cellophane. ...

See also

• ADME
• Barrer
• Osmosis
• Reverse osmosis