The molecular sieve is a kind of the crystal aluminosilicate attributing to its even pore size and much higher specific surface areas. 

There are many excellent merits:


(1) The selective absorption as the different size and shape of molecules, that is to say, it only absorbs those molecules of which the diameter is less than the pore size of molecular sieve. 


(2) To those smaller polar molecules and the unsaturated molecules, it has the property of selective absorption. The bigger the polarity is, and the higher the unsaturation is, the stronger property of the selective absorption is. 


(3) It has much stronger property of water sorption too. No matter in the situations of higher temperature, larger space velocity, or lower content of water it is, there is rather higher capacity of water absorption.