Model Calculation of Sepiolite Surface Areas

Toshiyuki Hibino
1995 Clays and clay minerals  
In general, the N2-BET surface areas ofsepiolite samples range from 95 to 400 m2/g depending on deposits. The surface areas of five sepiolites, all varying in crystallite size, were measured on heating, and were compared with a model calculation. A sharp decrease in the surface area, due to crystal folding, was observed between 200* and 400.C. Both before and after the folding, each sepiolite sample had peculiar values. Our model sufficiently explains this difference in surface areas among the
more » ... amples. In the model, which is based on the Brauner-Preisinger structural model, surface area is a function of the crystaUite size and the ratios of the coverage for nitrogen adsorption on both the internal and external surfaces. These ratios of the coverage can be inversely estimated from the model. The ratios of the coverage on the internal surface are less than 0.19, and that on the external surface between 0.7 and 1.0.
doi:10.1346/ccmn.1995.0430401 fatcat:ekh7iuqih5cm3aebyqkikugml4