What is an ion membrane? Thank you

Ion membranes are used when electrolyzing saltwater; those imported ones perform well, while domestic ones are not very effective. Such things can generally be seen inside electrochemical plants.

We used ion-exchange membrane alkali; we really didn’t consider this issue. I’m not sure if this is the right answer (just found it); I’ll check what others have to say as well. Ion exchange membranes are divided into anion membranes and cation membranes; under the action of voltage, they separate the anions and cations in the solution onto the membrane respectively, and through electrochemical reactions, these ions are ultimately discharged through the concentrated water chamber

Are there membrane materials that, just like ion exchange resins, can undergo specific ion exchange – allowing ions that meet the requirements to pass through while rejecting those that do not, thereby achieving selective permeability?

Chinese name: Ion exchange membrane English name: ion exchange membranes A polymer membrane containing ion-containing groups, which has the ability to selectively permeate ions in solutions. Since it is primarily utilized for its ion-selective permeability in applications, it is also known as an ion-selective permeable membrane. 　　Based on their functions and structures, they can be divided into five types: cation exchange membranes, anion exchange membranes, amphoteric exchange membranes, intercalated ion exchange membranes, and polyelectrolyte composite membranes. The structure of the ion exchange membrane is the same as that of ion exchange resin, but it is in membrane form. 　　Ion exchange membranes can be divided into homogeneous and heterogeneous types. It is manufactured using polymer processing methods. ①Homogeneous membrane. First, a membrane is made from polymer materials such as styrene-butadiene rubber, cellulose derivatives, polytetrafluoroethylene, polytrifluorochloroethylene, polyvinylidene fluoride, and polyacrylonitrile. Then, monomers such as styrene and methyl methacrylate are introduced to polymerize within the membrane, after which the desired functional groups are introduced through chemical reactions. It can also be produced by the polymerization of monomers such as formaldehyde and phenol. ②Heterogeneous membrane. It is prepared by fully mixing ion exchange resins with a particle size of 200–400 mesh with ordinary film-forming polymer materials such as polystyrene and polyvinyl chloride, and then processing them into a film. To prevent it from becoming brittle and cracking due to drying out, it must be kept in water. 　　Ion exchange membranes are primarily used in seawater desalination, the desalination of glycerin and polyethylene glycol, the separation of radioactive elements, isotopes, and amino acids, the purification of organic and inorganic substances, the treatment of radioactive waste liquids, as well as in fuel cell membranes and selective electrodes.

Ion-exchange membrane caustic soda is produced by electrolyzing brine using an ion-exchange membrane method to obtain caustic soda (i.e., sodium hydroxide). The underlying principle lies in the use of a cation-exchange membrane, which possesses a special selective permeability: it allows only cations to pass through while preventing anions and gases from doing so. In other words, only H+ and Na+ can pass through, whereas Cl-, OH-, as well as the products formed at the electrodes, H2 and Cl2, cannot pass through. This prevents the mixing of the anodic product Cl2 with the cathodic product H2, which could otherwise lead to explosions. It also prevents Cl2 from reacting with another cathodic product, NaOH, to form NaClO, thereby maintaining the purity of the caustic soda. 　　The main production process for alkali production by electrolysis using ion exchange membrane technology: Refined saturated brine is fed into the anode chamber ； Pure water (with a certain amount of NaOH solution added) is introduced into the cathode chamber; when electricity is applied, H2O is discharged at the cathode surface to produce H2, while Na+ passes through the ion membrane from the anode chamber into the cathode chamber. The catholyte introduced into the cathode chamber at this point contains NaOH ； Cl‑ is discharged on the anode surface to produce Cl2. The electrolyzed brackish water is then led out of the anode chamber, and after having its concentration increased by adding table salt, it can be reused. 　　The reason pure water rather than a NaCl solution is injected into the cathode chamber is that the reaction occurring in the cathode chamber is 2H++2e‑=H2↑ ； Na+, on the other hand, can pass through the ion membrane to reach the cathode chamber and form a NaOH solution. However, at the start of electrolysis, in order to improve the electrical conductivity of the solution without introducing new impurities, a certain amount of NaOH solution is often added to the water in the cathode chamber. 　　The main raw material for the chlor-alkali industry is saturated brine; however, since crude brine contains impurities such as sediment, Ca2+, Mg2+, Fe3+, and SO42-, it does not meet the requirements for electrolysis, and therefore must be purified.