Far-IR spectroscopic studies on zeolite NaCaA

✍ Scribed by R.V. Jasra; N.V. Choudary; K.V. Rao; G.C. Pandey; S.G.T. Bhat

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 402 KB
• Volume: 211
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(93)85188-t

✦ Synopsis

The location of sodium and calcium cations in zeolite A has been studied using far-IR spectroscopy. Spectroscopic measurements show a shift in the vibrational spectra with the partial replacement of Na+ by Ca'+ cations in the zeolite matrix. The magnitude of these shifts is observed to be dependent upon the location of the exchanged cations in the matrix, the effect being more prominent in the region 170-230 cm-'. The zeolite having highest calcium content shows a new band at around 231 cm-'. Our studies show that for up to 76% calcium exchange of the zeolite, the calcium cations are located only at site A. When calcium exchange is 95%, these cations are located at sites B and C with no cation observed at site A. The unusual adsorption behavior of high calcium zeolite A has been ascribed to the calcium cations located at site B.