A molecular sieve is a material containing tiny pores of a precise ... is used as an adsorbent for gases etc. A molecular sieve is a material containing tiny pores of a precise and ... of this, they often function as a desiccant. A molecular sieve can adsorb water up to 22% of its own weight ... and water can diffuse.CHEMPACK supply five types of molecular sieves: 3A, 5A, 6A, 13X(10A), Cu-13X. Molecular Sieve