3A molecular sieve
3A adsorbent, a potassium-exchanged form of the type a molecular sieve, is an alkali metal aluminosilicate. 3A adsorbent will adsorb molecules with critical diameters up to 3 angstroms type. 

Applications
- 3A adsorbent is preferred for commercial dehydration of unsaturated hydrocarbon streams, such as cracked gas, ethylene, propylene, and cracked liquid olefins. 
- drying of polar liquids (methanol, ethanol, and hydroxide organic compound ). 
- drying refrigerants. 
- drying n2-h2 mixtures made by cracking of nh3.