molecular sieve 4A
1. Key Properties
- High Adsorption Capacity: Static water adsorption up to 22%-24% by weight.
- Rapid Adsorption: Efficient moisture absorption even in low-humidity environments.
- Thermal Stability: Can withstand regeneration at 300-350°C.
- Chemical Inertness: Resistant to acids, alkalis, and insoluble in water and organic solvents.
2. Applications
- Gas and Liquid Drying:
- Deep dehydration of industrial gases (e.g., air, hydrogen, natural gas).
- Drying of organic solvents like ethanol and benzene.
- Environmental Protection and Separation:
- Adsorption of acidic gases (CO₂, SO₂) for waste gas treatment.
- Separation of n-alkanes (from iso-alkanes and aromatics).
- Household and Industrial Chemistry:
- Detergent additive (replaces phosphates for water softening).
- Other Fields:
- Moisture-proofing in pharmaceutical packaging, laboratory desiccators.
3. Comparison with Other Molecular Sieves
Type | Pore Size (Å) | Primary Ion | Typical Adsorbed Molecules |
3A | 3 | K⁺ | H₂O, NH₃ |
4A | Na⁺ | Na⁺ | H₂O, CO₂, SO₂, C₂H₅OH |
5A | 5 | Ca²⁺ | n-Alkanes (C₃-C₁₄), O₂/N₂ |
13X | 10 | Na⁺ | Aromatics, large gas molecules |