Abstract: This paper shows quantitatively the consequence of adsorbed water on N2 or O2 adsorbed on LiLSX lithium exchanged low silica X zeolite. In the range of 0～32 H2O/u.c.(unit cell), water present in LiLSX sharply declined the capacity for N2 or O2 adsorption. The reason is that the adsorption mainly occurs on the Li＋ ions on the 32 SIII sites in LiLSX. When H2O molecules residual after the desorption of hydrated LiLSX are adsorbed tightly on Li＋ at SIII site, they block the adsorption of nitrogen or oxygen. Water molecules introduced from outside into the dehydrated LiLSX influenc the adsorption of nitrogen less seriously than the residual water molecules do, because of the heterogeneity of adsorption sites and the diffusion behavior of water in LiLSX. When diffused into the inner part of a LiLSX particle, some water molecules may adsorb on weaker sites other than the strongest SIII sites.

Key words: Water, Adsorption, Air separation, Low silica X zeolite