anioonimembraanide

Anioonimembraanide, also known as anion exchange membranes, are specialized materials that selectively allow anions to pass through while restricting the passage of cations and neutral molecules. These membranes are typically polymeric and possess positively charged functional groups covalently attached to their structure. These positive charges attract and bind negatively charged ions (anions), facilitating their movement across the membrane under the influence of an electric potential or concentration gradient.

The composition and structure of anioonimembraanide can vary significantly depending on their intended application. Common polymers used include quaternary ammonium-functionalized polystyrene, poly(arylene ether sulfone), and polyvinylidene fluoride. The degree of cross-linking in the polymer matrix influences the membrane's mechanical strength and swelling behavior. The density and type of fixed positive charges dictate the membrane's selectivity and transport properties.

Anioonimembraanide find widespread use in various electrochemical and separation processes. They are crucial components in electrodialysis, a technique used for desalination and ion removal from water. In fuel cells, particularly anion exchange membrane fuel cells (AEMFCs), they serve as the electrolyte, conducting hydroxide ions. Other applications include diffusion dialysis for acid recovery, electro-deionization, and as selective barriers in battery technologies. The performance of these membranes is often characterized by their conductivity, anion exchange capacity, selectivity, and stability in different chemical environments.