Molecular Sieve 13X is the sodium form of the type X crystal and has a much larger pore opening than the type A crystals.  It will adsorb molecules with a kinetic diameter of less than 9 Angstrom (0.9 nm) and exclude those larger.
It also has the highest theoretical capacity of the common adsorbents and very good mass transfer rates. It can remove impurities too large to fit into a type A crystal and is commonly used to separate nitrogen from oxygen.

 Application 
- Removal of CO2 and moisture from air (air pre-purification) and other gases.
- Separation of enriched oxygen from air.  
- Removal of mercaptans and hydrogen sulphide from natural gas.
- Removal of mercaptans and hydrpogen sulphide from hydrocarbon liquid streams (LPG, butane, propane etc.)
- Catalyst protection, removal of oxygenates from hydrocarbons (olefin streams).
- Removal of n-chained compositions from aromatics.
- Production of bulk oxygen in PSA units .
- Production of medical oxygen in small scale oxygen concentrators