Zeolite itself has a multi-regular pore structure, and its pores are comparable to the molecular size of general substances, with a diameter of about 0.3~1nm, and its specific surface area is as high as 400~800m2/g. The special physical structure makes zeolite have two adsorption characteristics: selective adsorption and efficient adsorption.

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.