dialyse
- Domaine
-
- chimie
- Date
Terme :
- dialyse n. f.
Traductions
-
anglais
Date :Définition
The diffusion of a substance in solution through a microporous membrane; this process permits separation of smaller from larger molecules in a solution and thus might be called molecular filtration. The membranes used are of parchment, collodion, cellophane, or other cellulosic material; many have a pore size of 100 angstroms or less. In nature, plant cell walls act as osmotic diffusion membranes.
Note :
The rate of diffusion varies with the particle size and concentration of the dissolved substances; sodium chloride passes three times as quickly as sucrose, while macromolecules penetrate extremely slowly, if at all. Colloids were originally distinguished from crystalloids on this basis by Thomas Graham: proteins and other high-polymers tend to be held back or retained by a parchment membrane, whereas salts, sugars, etc., pass through it with varying degrees of ease.
Terme :
- dialysis
Terme associé :
- molecular filtration