Monitoring, by Inverse Gas Chromatography, of the Variation of the Surface Energetic Heterogeneity of Ground Muscovite Samples

Abstract

A layered mineral, like muscovite, is a good model of a heterogeneous solid because it presents two types of crystalline surfaces: basal and lateral surfaces. A convenient method for changing its degree of surface heterogeneity is to submit muscovite to a grinding process, creating new surfaces: either basal surfaces if the delamination of the crystal is the dominant process or lateral surfaces if comminution is prevalent. The aim of the present work is to demonstrate how inverse gas chromatography, combined with an original method of calculation of the adsorption energy distribution functions, is a very sensitive method to monitor the evolution of the surface heterogeneity of muscovite ground in the presence of different grinding additives such as glutaric acid (0.5% in aqueous solution) or potassium chloride (1 M in aqueous solution). It is shown that the latter favors the delamination of the muscovite crystal whereas the former induces the comminution of the crystal leading to an increase of lateral surfaces.

Influence of different dry milling processes on the properties of an attapulgite clay, contribution of inverse gas chromatography

“…Therefore, the probes, which are clearly identified molecules such as alkanes, acidic or basic molecules, are used to determine surface properties of the material packed into the column. In mineral field, Balard and Papirer showed the applicability of IGC to evaluate changes in the interactivity, morphology and heterogeneity of the solid surface after a grinding treatment [18][19][20]. In the present study, IGC was used to examine the modifications upon grinding of the surface properties of an Algerian attapulgite.…”

“…On the other hand, the shape analysis of the isotherm reveals the distribution functions of the adsorption energy sites (DF), which are related to the surface heterogeneity of the column packing. The calculation of DF is based on a physical adsorption model, which assumes that the global isotherm can be considered to be the sum of local isotherms of adsorption on isoenergetic domains (patchwork model) [18,19,34]. Thus, the distribution function of the relative abundance of each type of domain, having the same characteristic energy of interaction (ε), is given by the following integral (Eq.…”

Effect of hydration and thermal treatment on ceria surface using non-intrusive techniques

“…1a BET measurement requires thermal treatment which might modify surface state. The distribution function is calculated as described by Balard et al [45] using Rudzinski-Jagiello approximation based on a model assuming that the global isotherm is a sum of local isotherms corresponding to isoenergetic domains. Then the distribution function is related to the proportion of each domain on the surface.…”

Surface characterization of salmeterol xinafoate powders by inverse gas chromatography at finite coverage

“…Although regarded as a relatively new analytical tool in pharmacy, IGC at finite concentration has been applied extensively to full surface characterization of a number of nonpharmaceutical materials, for example, pitch‐based carbon fibers,5 poly( p ‐phenyleneterephthalamide) (PPTA)‐based fibers,6,7 ground muscovite samples,8 illites and kaolinites,9 graphite, carbon black, fullerene samples,10 etc. In all these studies, the technique has proved useful for revealing subtle differences in surface properties between various specially surface‐treated materials, which is otherwise not feasible with conventional IGC analysis at infinite dilution.…”