The 4A molecular sieve is an alkali metal aluminosilicate with an effective pore opening of approximately 4 angstroms. The sodium form of type A is widely used as a general-purpose drying agent and has good physical and adsorption properties. Type 4A beads can be used to adsorb water, ammonia, methanol, ethanol and carbon dioxide. This type of molecular sieve is often used to remove moisture from gas and liquid streams, where co-adsorption of sulfur compounds and carbon dioxide is not a concern.