Electrodialysis (ED) membranes are the core separation material of electrodialysis systems. Under a direct current electric field, the selective permeability of ion-exchange membranes causes cations and anions to migrate directionally, achieving desalination, concentration, or salt separation of the feed solution; they are a fundamental component of electromembrane processes.
Structure and Types
- Cation-exchange membrane: fixed groups are negatively charged, allowing cations to pass while blocking anions.
- Anion-exchange membrane: fixed groups are positively charged, allowing anions to pass while blocking cations.
- By application, they are divided into general electrodialysis membranes, monovalent-selective membranes, proton-blocking anion-exchange membranes, bipolar membranes, and other specialized types.
Product Features
- High selective permeability allows effective desalination and concentration in relatively low concentration ranges.
- Low membrane surface resistance helps reduce the electrical energy consumption of the electrodialysis process.
- Good chemical stability allows use in operating conditions involving acids, alkalis, and certain oxidizing media.
- Mechanical strength meets the assembly requirements for repeated assembly and compression of the membrane stack.
Application Industries
- Brackish water desalination, industrial wastewater desalination, and material desalination and purification.
- Concentration and volume reduction of high-salinity wastewater and front-end treatment for zero liquid discharge (ZLD).
- Separation of organic matter from inorganic salts, and resource recovery of acids, alkalis, and salts.
- Desalination and purification of food, pharmaceutical, and chemical materials.
Specifications and Models
| Parameter | Unit | Typical value |
|---|---|---|
| Membrane Type | — | Cation-exchange membrane / anion-exchange membrane |
| Area Resistance | Ω·cm² | 1–10 (typical) |
| Permselectivity | % | ≥ 90 (typical) |
| Water Content | % | 20–45 (typical) |
| Exchange Capacity | mmol/g | 1.5–2.5 (typical) |
| Thickness | mm | 0.15–0.40 (typical) |
The data in the table are common ranges for similar equipment and are for selection reference only; specific specifications, models, materials, connections, and control methods must be confirmed during the selection stage based on water quality, treatment scale, and site conditions.