Ionisäätökalvot

Ionisäätökalvot, often translated as ion-exchange membranes, are essential components in various electrochemical and separation processes. These specialized membranes are designed to selectively allow the passage of certain ions while blocking others. This selectivity is achieved through the presence of charged functional groups immobilized within the membrane matrix. Cation-exchange membranes possess negatively charged groups, enabling them to exchange cations (positively charged ions) from a solution. Conversely, anion-exchange membranes contain positively charged groups, facilitating the exchange of anions (negatively charged ions).

The underlying principle of ion-exchange membranes relies on the Donnan exclusion effect. When a membrane is in contact with an electrolyte solution, ions of the same charge as the membrane's fixed charges are repelled, while ions of the opposite charge are attracted and can permeate through the membrane. The degree of ion selectivity and permeability depends on factors such as the ion's size, charge, and hydration, as well as the membrane's pore size, polymer structure, and fixed charge concentration.

Ionisäätökalvot find widespread applications in numerous fields. They are crucial in electrodialysis for water desalination and purification, where they separate salts from water. In chlor-alkali processes, they are used to produce chlorine and sodium hydroxide. Furthermore, these membranes are employed in fuel cells to transport ions, in batteries for ion separation, and in various chemical processes for purification and concentration of ionic species. Their ability to selectively manage ion transport makes them indispensable for efficient and sustainable technological solutions.