the pore size of 4A molecular sieve is 4A, and it can adsorb water, methanol, ethanol, hydrogen sulfide, sulfur dioxide, carbon dioxide, ethylene, and propylene. It does not adsorb any molecule with a diameter greater than 4A (including propane), and its selective adsorption performance for water is higher than that of any other molecule. It is one of the most widely used molecular sieve varieties in industry.