3A molecular sieves are the potassium form of aluminosilicate zeolite A. Their structure forms a network of pores approximately 3 angstroms in diameter, through which only very small molecules such as water can pass. This makes them useful for removing water from compounds such as ethanol and other light hydrocarbons. They can absorb up to 20% of their weight of water, depending on the surrounding water concentration and other conditions. They can be dried for reuse by heating at 200-300C (400-600F).-