CATIONIC MIXED PILLARED LAYER CLAYS - INFRARED AND MOSSBAUER CHARACTERISTICS OF THE PILLARING AGENTS AND PILLARED STRUCTURES IN FE,AL AND CR,AL PILLARED MONTMORILLONITES

Pillared layer clays containing Fe,Al or Cr,Al mixed pillars were synt hesized and characterized with mid and far FT-IR and Fe-57 Mossbauer s pectroscopies. Spectra of the pillaring ions and the pillared material s indicated that co-hydrolysis and co-pillaring occurred. Isomorphous substitution of either tetrahedral or octahedral Al in the Al-13-Keggi n ion did not take place. The layers of montmorillonite were propped a part by a mixture of [AlO4Al12(OH)(24)(H2O)(12)](7+) Keggin ions and h ydrous iron oxide or hydrous chromium oxide, alternately. (C) 1997 Els evier Science B.V.