Interparticle Potential Energies in Na-Montmorillonite Clay Suspensions

Abstract

Abstract-The small angle X-ray scattering data obtained in an earlier investigation of a series of Na-montmorillonite clay samples containing varying concentrations of sodium metaphosphate have been used to calculate the potential energy qS(x) of the interaction between two isolated parallel clay platelets separated by a distance x. All &(x) curves have the form expected for Na-montmorillonite. In each curve there is a potential well for a platelet separation approximately equal to the most probable separation distance determined in the earlier study. Because the depth of the potential well is of the order of 0-01 eV for all samples, the attractive forces are relatively weak. While the calculated qS(x) functions are not highly accurate, in future investigations precautions can be taken to increase the reliability of the computed potential energy functions. This preliminary study suggests that determination ofqS(x) from small angle X-ray scattering data can be a useful method for quantitative study of interparticle forces in Na-montmorillonite clays.

Invalidity of deriving interparticle distance in clay–water systems using the experimental structure factor maximum obtained by small-angle scattering

“…If we relate the clay particles' orientational (i.e., organizational) change that results from the phosphate treatment to the disappearance of the experimental S(q) maximum, it is not difficult to arrive at the conclusion that the local, short-range ordering of clay particles responsible for the experimental S(q) maximum is related to the edge-face oriented interaction of particles (Figs. [2][3][4][5]. It is particularly worthwhile to examine the experimental S(q) of illite samples in Fig.…”

“…Various properties have been studied to understand these minerals' colloidal behavior such as the interparticle spacing or swelling, sol/gel transition, and flocculation/aggregation behavior [1]. Small-angle scattering is a method that has been used to determine the particle dimensions, interparticle spacing, and particle organization in solution or suspension [2][3][4][5][6][7][8][9][10][11].…”

“…Hight et al [3] independently derived an identical Fourier transform to treat their SAXS data allowing them to study the interparticle distances of clay particles in concentrated gels and in the presence of multivalent cations. Other studies were published by this group using this approach [4,17]. In their work, the distance distribution function, P (r), is given as…”

Thickness and Surface Characteristics of Colloidal 2:1 Aluminosilicates Using an Indirect Fourier Transform of Small-Angle X-Ray Scattering Data

“…These studies have both theoretical and industrial significance. The thickness, interparticle spacing in hydrated states, and the influence of interparticle forces fall into the characterization length scale of SAXS and have been investigated by this method in the past (Hight et al, 1960(Hight et al, , 1962Taylor and Schmidt, 1969;Morvan et aL, 1994;Pignon et al, 1997;Saunders et al, 1999).…”