Infrared spectroscopic studies of melt-deposited salt occlusion by zeolites

Abstract

Sodium nitrate is occluded by the zeolites NaX and NaA. In addition to occluded nitrate, adherent nitrate appears to contribute to the infrared spectra of most zeolite+NaNO₃ systems. A lattice mode has been detected for the system NaA+NaNO₃, which is interpreted in terms of an ordered occluded phase. Evidence indicates that both occlusion and cation exchange occur in the system NaA+LiNO₃. The extent of occlusion of NaNO₃ by NaX is much less than by NaA. Interaction between the zeolitic cation and the occluded phase is not significant even when the zeolitic cation is strongly coordinating (e.g. Zn²⁺). Little, if any, KSCN is occluded by zeolites NaA and NaX, and KSCN appears to react on the internal surface of ZnX.