Basal spacing, pillared smectites

Pillared clays are smectite minerals or iUite-smectite minerals that have been stmcturaHy modified to contain pillars of stable inorganic oxide. The pillars prop open the smectite stmcture so they have a basal space of approximately 3.0 nm. Typical metals in the pillars include Al, Zr, Ti, Ce, and Fe, and these materials are used in catalytic processes to crack heavy cmde oils (110—112). 

Silicon oxide / Aluminum oxide pillared smectites. Si02/Al203-pillared smectites were prepared using two different methods (6). The surface areas of the pillared products decreased with increasing Si/Al-ratio in the pillaring solution while the basal spacings were essentially independent of this ratio. 

From these data it is concluded that the basal spacing and BET specific surface area are not sufficient by themselves to represent the potential activity as adsorbents and/or catalysts of the pillared-smectites. 

Pr/Al- and Nd/Al-solutions treated at 120-160°C for 12-96 h did not yield large-pore pillared products. All samples prepared from these solutions showed basal spacings in the range 19-20 A which is within the range characteristic for conventional Al-pillared smectites. Autoclave treatment of RE-free ACH-solutions at 120-160°C for 12-96 h resulted in the formation of colloidal dispersions or geis of boehmite or pseudoboehmite. 

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