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S is the current density (flux) outward through the membrane carried by ion S, measured in amperes per square meter (A·m −2) P S is the permeability of the membrane for ion S measured in m·s −1; z S is the valence of ion S; V m is the transmembrane potential in volts
An ion-exchange membrane is a semi-permeable membrane that transports certain dissolved ions, while blocking other ions or neutral molecules. [1] Ion-exchange membranes are therefore electrically conductive. They are often used in desalination and chemical recovery applications, moving ions from one solution to another with little passage of ...
The process of permeation involves the diffusion of molecules, called the permeant, through a membrane or interface. Permeation works through diffusion; the permeant will move from high concentration to low concentration across the interface. A material can be semipermeable, with the presence of a semipermeable membrane. Only molecules or ions ...
In cellular biology, membrane transport refers to the collection of mechanisms that regulate the passage of solutes such as ions and small molecules through biological membranes, which are lipid bilayers that contain proteins embedded in them. The regulation of passage through the membrane is due to selective membrane permeability – a ...
Proton-exchange membranes are primarily characterized by proton conductivity (σ), methanol permeability (P), and thermal stability. [5] PEM fuel cells use a solid polymer membrane (a thin plastic film) which is permeable to protons when it is saturated with water, but it does not conduct electrons.
For example, 4% electrical steel has an initial relative permeability (at or near 0 T) of 2,000 and a maximum of 38,000 at T = 1 [5] [6] and different range of values at different percent of Si and manufacturing process, and, indeed, the relative permeability of any material at a sufficiently high field strength trends toward 1 (at magnetic ...
Anion exchange membranes are used in electrolytic cells and fuel cells to separate reactants present around the two electrodes while transporting the anions essential for the cell operation. An important example is the hydroxide anion exchange membrane used to separate the electrodes of a direct methanol fuel cell (DMFC) [ 1 ] or direct-ethanol ...
These membranes generally require high ionic conductivity, low permeability, thermal and hydrolytic stability, and morphological and mechanical stability. [ 7 ] [ 10 ] An example of membranes made from conductive polymer selective barriers in multifunctional micelles . [ 10 ]