Adsorption of zeolite molecular sieve is a physical change process. The reason for adsorption is mainly a molecular gravitational force on the surface of the solid "surface force", when the fluid flow, some molecules in the fluid due to irregular movement and collision to the surface of the adsorbent, molecular concentration on the surface, so that the number of such molecules in the fluid to reduce the purpose of separation and removal.

Molecular sieve is a class of adsorbent or film-like substance with uniform micropores, mainly composed of silicon, aluminum, oxygen and some other metal cations, whose pore size is comparable to the general molecular size, according to its effective pore size to sieve various fluid molecules.