jonväxlingsmembran

A jonväxlingsmembran, or ion-exchange membrane, is a semipermeable membrane that allows for the passage of specific ions while blocking others. This selective permeability is achieved through the presence of charged functional groups embedded within the membrane matrix. These groups can be either positively charged (anion-exchange membranes) or negatively charged (cation-exchange membranes).

When a solution containing various ions comes into contact with an ion-exchange membrane, ions with a charge opposite to that of the membrane's functional groups are attracted to the membrane and can pass through it. Conversely, ions with the same charge are repelled. The degree of selectivity depends on the nature and density of the charged groups, as well as the membrane's physical structure.

Ion-exchange membranes are crucial components in a wide range of electrochemical and separation processes. They are extensively used in electrodialysis for water desalination and purification, where they separate salt ions from water. In fuel cells, they act as electrolytes, facilitating the transport of ions between the anode and cathode. Other applications include the production of pure water, the separation of valuable metals, and in chlor-alkali processes for producing chlorine and sodium hydroxide. The development of advanced ion-exchange membranes with improved selectivity, conductivity, and durability continues to be an active area of research.