PILC and Acid-Treated Clay as Supports

In preparing catalysts and 7r-complexation sorbents, an inert support with a high surface area is often needed. The supports are, however, not always inert. For example, strong metal-support interactions are known in catalysis (Ruckenstein, 1987). The effects of different supports (silica vs. alumina) for r-complexation by AgNOs have also been noted (Padin and Yang, 2(X)0). 

Pillared clays and acid-treated clays are two types of supports that have shown interesting properties. They are discussed separately below. 

Steepness of the isotherm beyond the monolayer region, that is, point B or where the knee is located, is a direct reflection of the surface energy heterogeneity. Mathematically, the factor s in the Unilam (i.e., uniform Langmuir) isotherm is an indicator of the steepness of this portion of the isotherm, and is hence referred to as the heterogeneity parameter. The Unilam isotherm has been discussed by Valenzuela and Myers (1989) and by Do (1998). It is given by  

From the results of Cheng and Yang, it is clear that using the PILC support results in a higher value for This is likely caused by the heterogeneous nature of the PILC, because the PILC contains at least two different types of surfaces that on the pillars and that on the clay layers. 

CARBON NANOTUBES, PILLARED CLAYS, AND POLYMERIC RESINS 

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