MMO Coating Plate for Electrodialysis

MMO Coating Plate for Electrodialysis

Electrodialysis uses the selective permeability of semipermeable membranes to separate different solute particles (such as ions). When dialysis is conducted under an electric field, the phenomenon is called electrodialysis, where charged solute particles (ions) in the solution migrate through the membrane. The technology of using electrodialysis for purification and separation of substances is known as electrodialysis, developed in the 1950s. Initially used for seawater desalination, it is now widely applied in the chemical, light, metallurgical, paper, and pharmaceutical industries. It is particularly valued for producing pure water and treating industrial waste, such as acid and alkali recovery, electroplating waste treatment, and recovering useful substances from industrial wastewater.

Essentially, electrodialysis can be considered a desalination technology because various waters (including natural water, tap water, and industrial wastewater) contain certain amounts of salts. Under the influence of a direct current (DC) electric field, the anions and cations that make up these salts migrate in opposite directions. If an electrodialyzer contains both anion and cation exchange membranes, ions will move through these membranes, reducing salt concentration in the middle compartment while increasing ion concentration near the electrodes. In the middle compartment, desalination is achieved. In practical applications, an electrodialyzer is not composed of just one pair of anion and cation exchange membranes but rather hundreds or even thousands of membrane pairs, greatly improving efficiency.

Applications of Electrodialyzers

Currently, electrodialyzers have a wide range of applications, including water desalination, seawater concentration for salt production, refining dairy products, deacidifying and purifying fruit juices, and producing chemical products. They are also used in the food and light industries to produce pure water, and in the electronics and pharmaceutical industries for pretreatment to produce high-purity water. They can also be used for primary softening and desalination of boiler feed water, desalination of brackish water for drinking, and in various industries such as electronics, pharmaceuticals, chemicals, thermal power, food, beer, beverages, printing and dyeing, and coating for Water treatment. Additionally, electrodialysis can be used for the treatment of wastewater and waste liquids.

Electrodialysis Process

Under an applied DC electric field, the selective permeability of ion exchange membranes (i.e., cation membranes allow only cations to pass through, and anion membranes allow only anions to pass through) causes the directional migration of anions and cations in the water, thus achieving the separation of ions from water. Between the cathode and anode, several alternately arranged cation and anion membranes are placed, allowing water to pass through the compartments formed by these membranes and the electrodes. When the electrodes at both ends are connected to a DC power source, the anions and cations in the water migrate towards the anode and cathode, respectively. Due to the selective permeability of the cation and anion membranes, alternating compartments with reduced ion concentration (dilution chambers) and increased ion concentration (concentration chambers) are formed. At the same time, oxidation-reduction reactions occur at both electrodes, resulting in the cathode chamber becoming alkaline and scaling, while the anode chamber becomes acidic and corrodes. Therefore, in the electrodialysis process, the consumption of electrical energy is mainly used to overcome the resistance encountered by the current as it passes through the solution and membranes, as well as the electrode reactions.

Titanium Anode Plate / MMO Titanium Anode for Electrodialysis

• Base Material: Industrial pure titanium, Grade: TA1
• Surface Precious Metal Coating: RuO2+IrO2+X