PREPARATION AND CHARACTERIZATION OF ZIRCONIUM PILLARED LAPONITE AND HECTORITE

The Zr-pillaring of natural hectorite and synthetic laponite clay was investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) to character ize the different substrates. The difference in particle size of both clays is responsible for their differences in crystallinity, surface a rea (SA) and micropore volume (mu PV) and consequently for their pilla red forms too. Pre-adsorption of ethylenediamine in the interlayer spa ce of laponite is performed in order to reduce the important contribut ion of edge-to-face and edge-to-edge stacking of the clay layers and c reating a more homogeneous substrate for pillaring. As is proven by XR D, TGA and FTIR, ethylenediamine is exchanged completely for the Zr-pi llaring precursors during the pillaring reaction. Surface areas and mi cropore volumes of, respectively, 482 m(2)/g and 0.34 cm(3)/g for Zr-p illared laponite and 171 m(2)/g and 0.064 cm(3)/g for Zr-pillared hect orite after calcination are obtained. Through pillaring, especially sm all pores (< 0.71 nm), additional secondary micropores are formed with laponite while for hectorite, pores over a broad size range are obser ved. The prepared pillared interlayered clays (PILCs) were tested for their gas adsorption behaviour. Gas adsorption measurements on Zr-lapo nite reveal high adsorption capacities for N-2 and O-2 with a low N-2/ O-2 selectivity at 0 degrees C.