activated alumina, pseudoboehmite, Zibo XiangRun Environment Engineering Co., Ltd.

Activated alumina and molecular sieve are beads.  They perform the same process (they adsorb material at a molecular level), and they both have regenerative properties (you can re-use the material once the desiccant has reached capacity) yet they are two completely different products.  So the question is, with so many similarities, how to choose right activated alumina and molecular sieve?

Their raw material is different.  Activated alumina is made out of aluminum oxide that is highly porous, while molecular sieve is made out crystalline metal alumino-silicates.  It means the pores on molecular sieve can be shaped into specific sizes most commonly seen as 3A, 4A, 5A, and 13X, where as pores of activated alumina do not have specifically measured sizes.  This means molecular sieve can be used to separate certain molecules of specific sizes from one another, for example removing ammonia from natural gas streams.

Activated alumina can’t adsorb the large variety of materials or separate certain molecules from one another, however,  Molecular sieves is effective in this process like ethanol dehydration.  This is because activated alumina would be able to adsorb both ethanol and water molecules and thus no separation would occur.

Molecular sieve is not able to adsorb as much water but if you needed to reduce water to very low amount, up to 0.1ppm. 

Molecular sieve can also be used to separate specific molecules from one another, due to the customization of their pore sizes.  For example you can separate water from ethanol, and carbon dioxide, ammonia, and larger hydrocarbons from natural gas streams, which is something activated alumina can’t do, or won’t do with same efficiency.