Exchange, X-ray and IR spectral behaviour of lanthanum and praseodymium exchanged zeolite X

Abstract

Exchange behaviour of lanthanum and praseodymium ions in zeolite X involves three steps: preferential exchange, intrazeolitic exchange and irreversible exchange. At room temperature, higher exchange has been observed with La(III) than with Pr(III) which is attributed to the smaller hydrosphere of lanthanum than praseodymium. IR spectra of these zeolites in KBr pellets show a shift in the major Si - O stretching vibration of 972 cm^-1 to higher frequencies. Their X-ray diffraction patterns remain unchanged except a large decrease of the line intensities caused by the absorption of X-rays by heavy La(III)and Pr(III)ions.