Molecular sieves act as adsorbents and desiccants. The sieves have small pores to absorb the moisture. The pore size of the sieve is meant to be bigger than the particle size so that the sieves can absorb the moisture particles. The molecular sieves are majorly used as a drying agent for liquids and gases.
Additionally, the sieves bind nitrogen, separating it from oxygen in the air and has made it the ideal adsorbent for portable oxygen concentrators. Most oxygen concentrators use either the pressure swing adsorption or the vacuum pressure swing adsorption. PSA and VPSA are used to separate high-purity medical grade oxygen from ambient air. The same is achieved by passing airflow over a molecular sieve cartridge within the concentrator.
