Comparative Study of the Texture of Montmorillonites Pillared with Aluminum and Aluminum/Cerium

Abstract

This study compared the textural characterization of montmorillonite pillared with mixed aluminum/ cerium pillars with that of a sample pillared only with aluminum. In addition to the microporosity due to the aluminum pillars, the AlCe-pillared sample exhibited a new porous system, with a pore size at the limit between microporosity and mesoporosity. The pore size distribution determined by the density functional theory and Horvarth-Kawazoe methods allowed estimation of pore volume and indicated two different types of pore in the AlCe-pillared sample. The two types of pore were also observed on t-plot analysis. The presence of larger pores in the AlCe-pillared sample is due to the inorganic polyoxycations intercalated between the clay layers. These polyoxycations are larger than the Keggin ion intercalated in the sample pillared with aluminum alone.

Effects of Exchange Titanium Cations on the Pore Structure and Adsorption Characteristics of Montmorillonite

“…2, the evaluation of D from Eqs. [2] and [3] for nitrogen isotherms on Ti and Ca montmorillonite is illustrated and the results are presented in Table 1. For the case of the Ti montmorillonite sample, the desorption isotherm suggests negligible capillary condensation in the mesopore range and we should use Eq.…”

“…For the case of the Ti montmorillonite sample, the desorption isotherm suggests negligible capillary condensation in the mesopore range and we should use Eq. [2] to evaluate D, while for the Ca montmorillonite, we should use Eq. [3] to estimate D. As demonstrated in Table 1, the D values for the two examined montmorillonite samples are distinct, indicating that the surface roughness for Ti and Ca montmorillonite is very different.…”

“…It is possible to modify the surface properties of clays greatly by replacing natural inorganic cations with other cations. The modification process may induce an enormous change in both the surface and pore structures of clays and then mediate the practical applications of clays (1)(2)(3). Modification of the surface characteristics of clay through ion-exchange processes has been studied intensively in recent years and its practical application to removing contaminants from water has been seriously considered (4)(5)(6)(7).…”

Preparation and characterization of novel composite AlCr-pillared clays and preliminary investigation for benzene adsorption

“…To improve the structure and acidity of mononuclear inorganic PILC, studies on preparing composite inorganic pillaring agents have emerged, in which a second component (e.g., M = Fe, Cu, Cr and Ln) is added to the Al inorganic pillaring agent (Mandalia and Crespin, 1998;Hernando et al, 2001;Lin et al, 2007;Mojović et al, 2009;Tomul and Balci, 2009). Taking AlM pillaring agents as an example, the general preparation process is similar to the preparation of an Al inorganic pillaring agent, except that the NaOH solution is titrated into the A1C1 3 and M solution with different Al/M molar ratios.…”

Adsorption of cadmium onto Al13-pillared acid-activated montmorillonite

“…Of these modifications, metal oxidepillared interlayered clays have been most extensively studied in recent years [8][9][10][11]. While pillared clays are commonly used as catalysts, they are also finding applications as novel adsorbents.…”