FTIR SPECTROSCOPIC STUDY OF THE ADSORPTION OF HYDROGEN-CYANIDE BY METALLO-OXIDE PILLARED CLAYS

Citation
J. Jamis et al., FTIR SPECTROSCOPIC STUDY OF THE ADSORPTION OF HYDROGEN-CYANIDE BY METALLO-OXIDE PILLARED CLAYS, Chemistry of materials, 7(11), 1995, pp. 2078-2085
Citations number
49
Categorie Soggetti
Chemistry Physical","Material Science
Journal title
ISSN journal
08974756
Volume
7
Issue
11
Year of publication
1995
Pages
2078 - 2085
Database
ISI
SICI code
0897-4756(1995)7:11<2078:FSSOTA>2.0.ZU;2-Y
Abstract
The IR spectra due to hydrogen cyanide adsorbed by montmorillonite, mo ntmorillonite pillared by the oxides of aluminum, zirconium, iron, tit anium and chromium, montmorillonite pillared by mixed oxides of alumin um/zirconium, chromium/zirconium, iron/zirconium, and chromium/iron/zi rconium, acid washed montmorillonite, and acid-washed montmorillonite pillared by oxides of aluminum and zirconium have been recorded at var ious temperatures of thermal pretreatment of the pillared clays. Simil ar measurements have been made on hectorite and hectorite pillared by the oxides of aluminum and zirconium. Substantial binding of hydrogen cyanide by Lewis acid sites on the oxide pillars of the clays has been shown to take place after heating the pillared clays to 673 K. The fo rmation of such centres on the oxide pillared montmorillonite falls in the order Al > Ti > Zr >> Fe, being undetectable for chromium. The ef fect of the oxide pillar on the sheet structure of the clay is the pro duction of binding sites on montmorillonite or hectorite similar to th ose observed in zeolite Y and, additionally, a distinctive site charac terized by an IR spectral band in the 2140 cm(-1) region which is thou ght to be formed by disruption of the sheet structure with participati on of the pillar material. The extent of formation of this site on the sheet structure of montmorillonite increases in the order of the oxid es of Al < Fe < Zr < Ti < Cr and again for hectorite its formation is small for pillaring by aluminum oxide and extensive for pillaring by z irconium oxide.