Vermiculites surface-modified

Vermiculite Surface Modified with Carnauba Wax for Oil Cleaning... 

Table 1.1 Basal plane spacing values of various surface-modified montmorillonites and vermiculites [8-13].

In the case of vermiculite, the short-chain organic cations do not penetrate into the interlayer space, and are adsorbed only on the external surface of the mineral. This is clearly seen from the analytical measurements, showing that only 0.06 meq/g of Na" " ions is substituted when Na-vermiculite is treated with tetramethylammonium salt solution, the total exchange capacity being equal to 1.5 meq/g. Therefore, the values of specific surface area obtained from water and hexane adsorption isotherms for the initial and [(CH3)4N] modified vermiculite are virtually the same (Table 3). Such a pronounced difference in the... 

Since water molecules can adsorb on the clay surface, water can be considered as a modifier. To investigate the hydration process of vermiculite, a calorimetric study was performed with the main results as shovm in this section. The vermicuhte sample used was the same as described in the previous section. 

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