ISOMORPHOUS SUBSTITUTION OF FE3+ IN LTL FRAMEWORK USING POTASSIUM FERRATE(VI)

Potassium ferrate, as a primary source of iron, has been investigated in the hydrothermal synthesis of zeolite LTL. Crystalline material wit h Fe(lll) incorporated into lattice sites was isolated from starting g els containing up to 0.825 mole fraction Fe2O3/Al2O3. The use of basic , tetrahedral iron species has extended previous maximum substitution levels. X-ray diffraction, infrared spectroscopy, chemical analysis, a nd electron microscopy provide evidence for the presence of framework iron, The development of new i.r. absorption bands in the asymmetric a nd symmetric Si-O-T stretching region, and the shift to lower wavenumb ers is accompanied by an increase in the interplanar spacings and unit -cell dimensions with increased Al3+ replacement. A change in morpholo gy is also observed.