The 4A molecular sieve provided by our company refers to sodium A-type aluminosilicate. 4A molecular sieve can adsorb molecules with a critical diameter not greater than 4A, and can adsorb water, methanol, ethanol, hydrogen sulfide, sulfur dioxide, carbon dioxide, ethylene, propylene, etc. Molecules adsorbed on type 3A molecular sieves can be adsorbed on type 4A.