Thermal behaviour of pure LiN3, NaN3, CsN3 and their mixture with the respective LiY-FAU, NaY-FAU, CsY-FAU zeolite was investigated by means of thermogravimetry and IR spectroscopy. Thermodesorption of CO2 was applied to compare the basicity of the alkali ionexchanged Y zeolites. Two of the investigated systems, the NaN3/NaY-FAU and the CsN3/CsY-FAU gave single, well defined and reproducible azide decomposition features rendering these samples to apply as catalyst precursors for preparation of zeolite with basic character.
Ion-exchange of transition metal ions into montmorillonite was investigated using two different ion-exchange procedures. Performing ion-exchange from aqueous solution of the respective metal ion leads to material possessing measurable BrØnsted acidity, while the solid-state exchange materials show predominantly Lewis acidity.
Authors:I. Pálinkó, I. Kiricsi, Gy. Tasi, and K. Varga
Natural montmorillonite was pillared by various polyhydroxy cations. The resulting pillared layer clays (PILCs) were characterized by X-ray fluorescence, X-ray diffraction (XRD) and infrared (IR) spectroscopies. The thermal behaviour of Al-PILC was investigated in detail by a combonation of XRD, derivatography IR spectroscopy and a comparison to natural montmorillonite is given. It was found that thermal stability of Al-PILC is lower than that of natural montmorillonite. However, heat treatment in the stability region results in significant sintering of natural montmorillonite, while the interlayer spacing of Al-PILC is hardly affected.
Authors:Judit Varga, Á. Fudala, J. Halász, and I. Kiricsi
The solid-state ion-exchange procedures of zeolites with Cu2+, Ni2+, Fe2+ and Co2+ salts can be resulted in prosperous catalysts for NO decomposition. Reactions taking place in solid-state between four transition metal cholirides and H-ZS-5 zeolite were investigated by means of a derivatograph. The results showed that irreversible consumption of surface -OH groups occurred with simultaneous bonding of the transition metal in the zeolite channel structure.